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Operating Manual

Thermovision 550

Thermovision 550 Operating Manual

Thermovision 550Operating Manual

Publ. No 557 084, Ed B AGEMA Infrared Systems AB, September 1997


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Contents

1. Introduction...................................................................... 11.1 System overview.................................................................................. 11.2 Unpacking ........................................................................................... 3

2. Controls and connections ................................................ 12.1 Direct access buttons ........................................................................... 12.2 Menu functions .................................................................................... 22.3 Connections ......................................................................................... 3

3. Getting started .............................................................................. 13.1 Adjusting and connecting .................................................................... 13.1.1 Lenses .................................................................................................. 13.1.2 PC-card................................................................................................ 13.1.3 Battery belt .......................................................................................... 23.1.4 Shoulder strap...................................................................................... 33.1.5 Headset ................................................................................................ 33.2 First time operation.............................................................................. 43.2.1 To get an image ................................................................................... 43.2.2 To set a new language.......................................................................... 53.2.3 To measure a temperature.................................................................... 53.2.4 To save an image ................................................................................. 53.2.5 To add a voice comment to an image .................................................. 63.2.6 To recall a previously stored image..................................................... 6

4. Operation ........................................................................................ 14.1 User interface (control functions) ........................................................ 14.2 Menu objects ....................................................................................... 34.2.1 Menu area ............................................................................................ 44.2.2 Control box.......................................................................................... 44.2.3 Dialogue box ....................................................................................... 54.2.4 Confirm box......................................................................................... 64.2.5 Result table .......................................................................................... 64.2.6 Data presentation ................................................................................. 74.2.7 Temperature scale................................................................................ 74.2.8 Status area............................................................................................ 74.2.9 Joystick control.................................................................................... 74.2.10 Critical information ............................................................................. 8


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4.3 File system........................................................................................... 94.3.1 Digital recording advantages ............................................................... 94.3.2 File organisation .................................................................................. 94.3.3 Naming files and directories ................................................................ 94.3.4 Naming files and directories in PC .................................................... 114.4 Menu functions .................................................................................. 114.4.1 File menu ........................................................................................... 114.4.2 Analysis menu.................................................................................... 164.4.3 Image menu ....................................................................................... 204.4.4 Setup menu ........................................................................................ 21

5. Battery system .................................................................. 15.1 Battery belt .......................................................................................... 15.2 Battery charging .................................................................................. 25.3 Useful notes on the battery system....................................................... 3

6. Thermal measurement technique ................................... 16.1 Introduction ......................................................................................... 16.2 Emissivity ............................................................................................ 26.3 Finding the emissivity of an object ...................................................... 46.4 Ambient temperature ........................................................................... 46.5 Distance and relative humidity ............................................................ 4

7. Theory of thermography ................................................. 17.1 Introduction ......................................................................................... 17.2 The electromagnetic spectrum............................................................. 17.3 Blackbody radiation............................................................................. 27.4 Non-blackbody emitters....................................................................... 77.5 Infrared semi-transparent materials ................................................... 10

8. Technical specifications............................................................. 18.1 Thermovision 550 camera................................................................. 18.2 Lenses .................................................................................................. 38.3 Input/output (connectors)..................................................................... 48.4 Battery charger .................................................................................... 68.5 Power supply ....................................................................................... 6


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WarrantyAll products manufactured by AGEMA Infrared Systems AB are warranted againstdefective materials and workmanship for a period of one (1) year from the deliverydate of the original purchase, provided such products have been under normalstorage, use and service, and in accordance with AGEMA’s instruction.

All products not manufactured by AGEMA included in systems delivered byAGEMA to the original purchaser carry the warranty, if any, of the particularsupplier only and AGEMA has no responsibility whatsoever for such products.

The warranty extends only to the original purchaser and is not transferable.It is not applicable to any product which has been subjected to misuse, neglect,accident or abnormal conditions of operation. Expendable parts are excluded fromthe warranty.

In the event of a defect in a product covered by this warranty the product shall notbe further used in order to prevent additional damage. The purchaser shall promptlyreport any defect to AGEMA or this warranty will not apply.

AGEMA will, at its option, repair or replace any such defective product withoutcharge if it, upon inspection, proves to be defective in material or workmanship andprovided that it is returned to AGEMA within the said one-year period.

AGEMA has no other obligation or liability for defects than above set forth.

No other warranty is expressed or implied. AGEMA specifically disclaims theimplied warranties of merchantability and fitness for a particular purpose.

AGEMA shall not be liable for any direct, indirect, special, incidental orconsequential loss or damage, whether based on contract, tort or any other legaltheory.


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Copyright by AGEMA Infrared Systems AB, 1996. All rights reserved worldwide. No partsof the software including source code may be reproduced, transmitted, transcribedor translated into any language or computer language in any form or by any means,electronic, magnetic, optical, manual or otherwise, without the prior writtenpermission of AGEMA Infrared Systems AB, Box 3, S-182 11 Danderyd, Sweden.

This manual may not, in whole or part, be copied, photocopied, reproduced,translated or transmitted to any electronic medium or machine readable formwithout prior consent, in writing, from AGEMA Infrared Systems AB.

TrademarksThermovision is a registered trademark of AGEMA Infrared Systems AB.

Quality AssuranceThe Quality Management System under which these products are developed andmanufactured has been certified in accordance with the standard for ISO 9001.

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AGEMA Infrared Systems AB is committed to a policy of continuousdevelopment; therefore we reserve the right to make changes and improvements toany of the products described in this manual without prior notice.

All functions described in this manual are not available in all different systems.


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1. Introduction

1.1. System overview

The AGEMA Thermovision 550 infrared condition monitoring system consists ofan IR-camera with a built-in 20° lens, a battery belt and a range of accessories.The IR-camera measures and images the emitted infrared radiation from an object.The fact that radiation is a function of object surface temperature makes it possiblefor the camera to calculate and display this temperature.

The Thermovision® 550 camera is dust and splash proof and shock and vibrationtested for use in the most demanding field conditions.It is a handheld truly portable camera which is lightweight and operates more than6 hours on the battery belt.A high resolution colour image is provided in real-time either in the integralviewfinder or on an external monitor.

The camera is very easy to use and is operated by using a few buttons which areconveniently placed on the camera allowing fingertip control of major functions.Also a built-in menu system gives easy access to an advanced simple to use camerasoftware for increased functionality.

To document the object under inspection it is possible to capture and store imagesonto a removable PC-Card. It is also possible to store, together with every image, avoice comment including information such as the object’s ID data and fieldconditions etc. This is done by making use of the head-set connected to the camera.

The images can be analysed either in the field by using the real-time measurementfunctions built into the camera, or in a PC by using the IRwin Report analysis andreporting software.

The PC-Card is moved from the camera to the PC . In the PC the images cannotonly be viewed and analysed, but the voice comment can also be played back.IRwin Report makes it very easy to create complete survey reports (containingnumerous IR images, photos, tables etc.) from the inspections.


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Figure 1:1 System overview with accessories


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1.2 Unpacking and assembly

On receipt of your Thermovision® 550 remove each component from the carryingcase and inspect them all against the delivery note.

The Thermovision® 550 system is supplied in a transport case. The systemcomprises:

Thermovision 550 Camera with built-in 20° lensPC-CardBatteries (4)Battery belt with an extra shoulder strapFast charger with cableShoulder strapVideo cableLens capOperating manualCalibration protocolTransport caseHeadset (not included in all version)

Optional accessories:Power supply with cable 5 ° lens10 ° lens40 ° lensExtension cable, 5 mPC-software, IRwin ReportHigh temperature optionsRemote control handleSplit systemCamera handleHeat shieldResearch upgrade with digital video output


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Figure 1:2. How to pack the Thermovision 550 in a transport case


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2. Controls and connections

2.1. Direct access buttonsThe camera is controlled by pressing the direct access buttons and/or usingthe joystick control.

A detailed description of each button’s function can be found in chapter 4 ofthis manual.

Figure.2:1

Joystick

A↵

Adjustableocular ring

ON/OFF

S

C


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Press the A (Auto) button to automatically get the “best image”in the viewfinder.When this button is pressed an automatic calibration is also performed.Holding down the A button for more than 1 sec. makes the camera perform the Automatic Measurement Range function.

Press the S (Store) button shortly to toggle between frozen imageand live images. To store the image to the PC-card hold the Sbutton down for more than 1 sec.

The ↵ (Enter) button brings up the menu system of the camerain the viewfinder. Make the selection in the menu by using thejoystick control. You accept the menu choice and quit the menu mode by pressing the ↵ button. The ↵ button also meansaccept or OK.

The C (Clear) button is used when you need to skip a menu selection without making any changes and leave the menu mode.The C button also means escape or NOT OK.

The green ON/OFF button is used to switch the power to thecamera on and off. Press the button to switch the camera on.Hold down the button for more than 2 sec. to switch the cameraoff.

The joystick button has various functions. At start up of thecamera the joystick is in the default mode controlling focus (up/down) and zoom (left/right).In the menu mode you use the joystick to select the appropriate function and to increase or decrease various parameter settings.

2.2 Menu functionsPressing the ↵ button brings up the menu in the viewfinder. Selections in themenu are made by using the joystick and the ↵ button. A detailed descriptionof the menu functions is provided in chapter 4 of this manual.

A

C

S

↵


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2.3 Connections

There are three connectors on the camera.

12V connector: Power cable from battery belt or power supply. This connectoralso provides S-VHS signals (or on some camera models 12-bit digital signals) andremote control signals when the optional 5 metres extension cable is used .

Headset connector: For voice annotation of images connect the headset here.

Video connector: Connect large monitors or standard VHS-video equipmentfor viewing or recording.

Figure 2:2 Connections 12V Video

Headset


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3. Getting started

3.1 Adjusting and connecting system components

3.1.1 LensesThe camera is equipped with a built-in 20° lens but optional 5°, 10° or 40° lensescan also be used.

To add the lens push the lens carefully into the bayonet on the camera, aligning thewhite dots on the camera bayonet and the lens. Turn the lens clockwise 45° tosecure the lens.

To release the lens turn it 45° anticlockwise and remove the lens.

The lens type is recognised by the camera and the correct calibration isautomatically used.

3.1.2 PC-cardThe recorded images with voice comments are stored on a removable PC-Carddisk.

To insert the PC-Card open the hatch by pressing the release button on the back ofthe camera downwards. Insert the disk with the connector side (i.e. the bottom sideof the disk) to the right and the connectors into the camera.

The camera will check that the PC-Card is OK after it has been inserted. This willbe indicated in the viewfinder by the words “Checking disk”.

To remove the PC card open the hatch and press the eject button.


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3.1.3 Battery beltInsert the four batteries into the compartments of the battery belt with theconnectors of the batteries facing down. Secure the batteries with the flaps that arecovering the compartments.

If only two batteries are to be used, place these as shown below and select themwith the switch.

Figure 3:1 Battery belt

Connect the battery cable from the battery belt to the 12V connector of the camera.

Put the belt around your waist with the batteries at the back and adjust for mostcomfortable length.

If necessary, the battery belt can be supported with the supplied extra strap overyour shoulder. To do this fasten the strap on the front and back of the battery beltinto the plastic attachments and adjust the length.

See also battery system , chapter 5.

Switch


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3.1.4 Shoulder strapTo fit the shoulder strap to the camera, pull back the safety clasp at the end of theshoulder strap by pressing down the release button. Pass the thin straps at the endsthrough the slits on the left and right back side of the camera. Lock the straps bypulling forward the safety clasp.

Adjust the length of the shoulder strap so that the camera rests comfortably on thechest when having the shoulder strap around your neck.

3.1.5 HeadsetConnect the headset to the headset connector on the camera.

Place the headset on your head with the plastic support above your ears on theopposite side of the headphone.

Adjust the position of the microphone to about 2-3 cm from your mouth.

The headset could be used with the headphone either to the left or to the right. Tochange the side of the microphone from front to back flip it up and over 270°.

On the cable there is also a clip to fasten the cable to the operator.


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3.2 First time operation

3.2.1 To get an imageConnect the cable from the battery belt to the 12 V connector on the right side ofthe camera

Remove the lens cover from the camera.

Hold the camera in the right palm and adjust the hand strap around the hand until acomfortable position is obtained. Ensure that the buttons are readily operable withyour fingers.

Press the green ON/OFF button to start the camera.

After approx. 15 seconds an image with an AGEMA logo will appear and will bedisplayed until the camera controls are ready for use.The camera is ready for use when the detector has been cooled down to its workingtemperature. This takes approx. 5 minutes and is indicated on the screen by thetext cooling down. Another way to determine whether the detector is cooled downis to listen to the sound from the cooler which becomes quieter as the workingtemperature of the detector is reached.

While the detector is cooling down it is still possible to look at stored images orchange the set-up of the camera to make it ready for use.

Adjust the viewfinder ocular ring to obtain the best display focus for your eyes.

Point the camera at a warm object to be viewed, like a face or a hand.

Press the A button to activate the auto adjust function resulting in a good image inthe viewfinder.

Adjust the focus of the camera by pressing the joystick up to focus further away ordown to focus on a closer distance until the sharpest image is reached.


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3.2.2 To set a new languageIf the camera is switched to the wrong language, press the ↵ button to make themenu system drop down. Go to local adaptations in the set-up menu i.e. the thirdfunction in the menu furthest right. Press ↵ which makes the local adaptations set-up panel appear. Go down to language (i.e. the third choice) and select therequired language by pressing the joystick to the right or left. When the correctlanguage is shown press ↵ to set the language.

3.2.3 To measure a temperaturePress the ↵ button to make the menu system drop down.

Go to the spot function in the menu tree by pressing the joystick in the desireddirection. The spot is located in the analysis menu.

Press the ↵ button when spot is marked.

The spot marker will now appear in the image and the measured temperature willbe shown in the upper right corner of the display.

To position the spot move it with the joystick. When the spot is correctly locatedpress ↵ to go back to normal function of the joystick (i.e. controlling focus andzoom).

3.2.4 To save an imagePress the A button and focus the image.

Press the S button to freeze the image.

If the image is OK hold down the S button for 1 second or until the filename (e.g.E123232) of the image appears.

If the frozen image is not to your liking press the S button briefly to go to live modeand try again.


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3.2.5 To add a voice comment to an imageConnect the headset to the headset connector and place it on your head. See also3.1.5

Press the A button and focus the image.

Freeze the image by pressing the S button for a short while.

Press the ↵ to get the menu system and go to voice comment... in the file menu byusing the joystick. Select voice comment... by pressing ↵. This will make thecontrol panel for the voice comment appear.

Hold down the S button while recording. The length of the comment is indicatedby the * signs in the control bar.

Playback in the headphone indicates that the recording is working .

To listen to the comment hold down the A button.

When the voice recording is complete press the ↵ button to save both the imageand the voice comment.

3.2.6 To recall a previously stored image and listen to a voicePress the ↵ button to make the menu system drop down.

Go to the open function in the menu tree by pressing the joystick in the desireddirection. Open is located in the file menu.

Press the ↵ button when open is marked.

A control bar for open files will now appear at the bottom of the screen.

To choose the image which you would like to open move the joystick up and down.If the image is in another directory go to the directory selection box by moving thejoystick to the right. When the required image is on the screen press ↵ to select theimage.


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To listen to the voice message go to the voice comment... function in the menu treeby pressing the joystick in the desired direction. Voice comment... is located in thefile menu. Press the ↵ button when voice comment... is marked.

A dialogue panel for voice comment... will now appear on the right side of thescreen.

To play back and listen to the message hold down the A button. To remove thevoice comment... dialogue panel press the C button.

To go to live mode again press the S button.


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4. Operation

4.1 User interface (Control functions)The most important functions can be accessed with the buttons described below.

JoystickThe joystick can be moved in four directions left, right, up and down.

Functionality in menu mode:• Change menu items and item values.

Functionality in measurement function mode• Move measurement functions on the screen , i.e. spot, area, profile and

isotherm.

Functionality in normal mode:• Joystick left/right: zooming out/in.• Joystick down/up: focusing near/far.

Joystick

ON/OFF

↵ A

S

C


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ON/OFF (green Button)Push the button once to switch the camera on. Hold down the button for more thantwo seconds to switch the camera off.

S ( Save) ButtonPush the button briefly to toggle between frozen and live images. A frozen image isindicated by the word frozen in the status area, see figure 4:1.

An image is saved by pressing the button for about one second until the filenamefor the saved image appears in the status area, e.g. Saving G0101-00.

A (Adjust) ButtonPush the A button to set the best image. The camera will automatically adjust theviewed temperature span and level and will also fix the palette for best contrast inall parts of the image. If the image is in live mode a calibration is performedautomatically. The exact function of the auto adjust button when pressed can bechanged in the setup.Automatic measurement range adjustment is made by pressing the button for about1 second.

↵ (Enter) ButtonThis button has different functions depending on which mode the camera is in i.e.normal (focus/zoom) mode or menu mode. However the ↵ button always meanscontinue, confirm or exit.Pressing ↵ in normal mode will bring up the menu system and put the camera inmenu mode. Pressing ↵ in menu mode:• Activates the selected function or command in the pull down menus.• Confirms and exit the selected choices.

C (Clear ) ButtonThis button clears/quits without changing anything.In menu mode:Normally removes the menu-system putting the camera in normal mode.In normal(focus/zoom) mode:Special featureWhile the C button is held down the level and span can be adjusted with thejoystick.Joystick left/right: decrease/increase span.Joystick down/up: decrease/increase level.


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4.2 Menu objectsThe menu system includes a number of different menu objects. This chapterdescribes the menu objects.

Figure 4:1 Menu system objects and layout.

AreaMeasurementfunction

Critical infoCooling down,Batt low etc.

DatapresentationOne to threerows.

Joystickcontrole.g. Spot pos,Area pos, etc.

Menu areaPull downmenus

Menu Area

Scale

Critical info

Joystick control

Data presentation

Pulldown menu

SpotMeasurementfunction

Result tableMeasurementpresentationarea.

Confirm boxe.g.Delete image-> No/Yes.

Dialogue boxe.g.Setupparameters

Control boxe.g. Open... ,Obj par...

Result table

Control box

Status text

Status texte.g. Frozen,Saving etc.

Dialogue box

Confirm box


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4.2.1 Menu areaThe menu area is reached by pressing the ↵ button which brings up the menusystem (see figure 4.1). Moving the joystick left/right brings up the different pulldown menus. Selecting an item in a pull down menu is done by moving the joystickup/down. The selected item is highlighted. Some of the functions might be markedgrey indicating that they cannot be activated under these conditions. This couldhappen for Open or Save if there is no PC-card disk inserted.

Actions when ↵ is pressed:• If the selected pull down menu item has three dots at the end (e.g. Open...) a

menu dialogue will show up on the screen.• Otherwise the selected menu item (e.g. Save) will be executed and the menu

area will be removed.

Pressing the C button will remove the pull down menu area and restore the normalfunction for the joystick i.e. focus/zoom.

4.2.2 Control boxSome function selections in the menu area result in showing a Control box in thebottom left-hand corner of the screen.

Figure 4:2 Control box

The Control box is a horizontal table with different selection possibilities. Theupper row contains the selection headings and the lower row the value/alternativefor each selection.

Joystick functions:• Left/Right: Change item.• Up/Down: Change item value/alternative.

The selected item is marked white/dark grey. Pressing the ↵ button saves changesand removes the Control box.Pressing the C button will remove the Control box, cancel the changes and put thecamera in normal mode i.e. focus/zoom function for the joystick.


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4.2.3 Dialogue boxSome function selections in the menu area result in showing a Dialogue box on thescreen.

Figure 4:3 Dialogue boxes, Horizontal lists and vertical list.

A Dialogue box contains either one or several horizontal selection items or onevertical selection item (see fig. above).

Joystick function, horizontal dialogue box• Up/Down: Change item.• Left/Right: Change item value/alternative.

Joystick function, vertical dialogue box• Up/Down: Change item value/alternative.

The selected item is marked white/dark grey. Pressing the ↵ button results in afunction dependent action (see chapter 4.4 Menu Functions).

Pressing the C button will normally remove the Dialogue box, cancel the changesand put the camera in normal mode i.e. focus/zoom function for the joystick.


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4.2.4 Confirm boxSome selections (pressing ↵ or C) result in a Confirm box appearing on the screen.See figure 4.8.

Joystick functionLeft/Right: Change item (e.g. Yes or No)The selected item is marked white/dark grey. Pressing the ↵ button normallyconfirms the action (removing the dialogue and confirm box) and puts the cameraback in normal mode, i.e. focus/zoom.Pressing the C button removes the Confirm box without any other action.

4.2.5 Result tableWhen a measurement function is active a result table is displayed in the upperright-hand corner of the screen. The first row contains the selected temperature unit(see local adaptation chapter 4.4.4) i.e. °C or °F. The second row contains themeasurement type i.e. Spot, Amin, Amax, Aavg, Cur or Iso and the correspondingtemperature value. If the isotherm is activated together with another measurementfunction, the Iso value is located under the measurement function e.g. Spot. If Difftemp (see Setup analysis chapter 4.4.4) is activated the difference temperature isdisplayed under the appropriate measurement function. The reference temperatureis displayed on the bottom row of the result table.

Special signs:---- Undefined temperature.< Temperature below range.> Temperature above range.* Uncalibrated, the temperature is outside calibrated range.

Figure 4:4 Result table, possible combinations.


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4.2.6 Data presentationThe data presentation is displayed on the first, second or third bottom lines of thescreen. In Setup-Image, data presentation can be selected in four different levels,None, Normal, Reduced or Extended. The background can either be solid ortransparent. See Chapter 4.4.4 (Setup-Image, Data:) for detailed information.

4.2.7 Temperature scaleThe temperature scale is displayed in the right-hand border of the screen. The scaleshows how the colours are distributed over the various temperatures in the imagewith high temperatures in the upper end and low temperatures in the lower end.The small boxes above and below the scale display which colours are used fortemperatures outside the scale. See also saturation colour, chapter 4.4.4.

4.2.8 Status areaThe Status area is shows the current action.Examples:Checking disk Is displayed when a PC-Card ATA disk is inserted.

Frozen Is displayed when the image is frozen.

Saving G0101-01 Is displayed during the time an image with the name G0101-01 is written to the disk.

Adjusting Is displayed during the time the camera performs an auto adjustment.

G0101-01 The recalled image name and the speaker symbol are displayed if the image contains a voice comment.

Zooming in/out Is displayed when changing zoom factor.

Focus far/near Is displayed when changing focus.

4.2.9 Joystick controlThe camera shows which measurement function is connected to the joystick.


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Joystick: Spot pos Joystick: Iso tempJoystick: Area size Joystick: Profile and cursor posC: Remove

4.2.10 Critical informationCritical camera information is displayed in the centre of the screen.Typical messages are:

Battery lowThe battery voltage is under a specified limit and the batteries will empty withinminutes.

Battery emptyThe battery voltage has dropped below a minimum. The camera will be switchedoff within 10 seconds.

Recalibrating cameraIs displayed when changing temperature range.

Cooling downIs displayed until the camera detector has reached its working temperature. TheCooling down message is removed when recalling images.

Cooler is offIs displayed when the cooler is switched off. The Cooler is off message is removedwhen recalling images.

Failed checking diskIs displayed if an error occurred during the disk checking procedure. The messagewill be displayed until the faulty disk is removed.

Unknown PC-cardIs displayed if a non ATA disk is inserted in the camera. The message will bedisplayed until the disk is removed.

Disk errorIs displayed if some kind of error is detected during reading/writing to the PC-Carddisk.


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4.3 File SystemThe Thermovision 550 uses the standard PC-card ATA hard/flash disks, withDOS file system, to record 12 bit-images and voice comments.

4.3.1 Digital recording advantagesDigital recording using PC-card ATA hard/flash disks offers a number ofadvantages when storing images with the Thermovision 550. Images can be storedand recalled later without loss of accuracy. Video recording, however, is dependenton the stability of the recording equipment for its accuracy, which can often bepoor.

4.3.2 File organisationThe camera only creates new inspection/working directories at the root level.Images are saved under an inspection/working directory.

Figure 4:5 File organisation example using Windows 3.11 File Manager.

The camera ignores image files located in the root directory. Directories located inan inspection/working directory are also ignored by the camera.

4.3.3 Naming files and directoriesWhen storing an image a name is automatically generated based on either thecurrent date or the current directory according to the selection made in the setup-save options menu

When storing an image or creating a new directory the name, based on currentdate, is generated according to the expression below.


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Image name: YMMDDnnn.EXT

Y= Least significant digit in the current year, converted to an equivalent letter (A=0 to J=9), e.g. 1996 -> G.

MM= Current month (01 to 12)DD= Current day (01 to 31)nnn= File/directory index.

If index [01..99] -> -NN, #NN if directory name.If index [100..999] -> NNN.

Example:The current date is 10/01/96 (10th January, 1996).Two images have already been stored on this date. The next image to be stored isallocated the prefix G0110-03.

G = digit 6 in 1996 converted to a letter.0110= 10th January03= File index (this is the third image generated in 10-January

1996).

No extension is used for directory names. The extension .IMG is used for imagenames. The extension is not presented in the camera.

When storing an image, the name, based on the current directory, is generatedaccording to the expression below.

Image name: DIRECnnn.IMG

DIREC=First 5 characters of the directory namennn= File/directory index.

If index [01..99] -> -NNIf index [100..999] -> NNN.

Example:The directory name is COMPANY.Two images have already been stored on this date. The next image to be stored isallocated the prefix COMPA-03.


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4.3.4 Naming files and directories in a PC

When creating directories in a PC there is no restriction of naming the directories,i.e. the camera can read all directories on the root level independently of chosendirectory name.

It is possible to rename image names created in the camera to any DOS approvedname, i.e. the camera can read image files independently of chosen image names,but the camera only accesses files with the extension IMG. If the extension for afile is renamed in a PC the camera ignores the file. On the other hand, if a non"AGEMA File Format" file has the IMG extension, the camera will display thecritical info "Bad file format" when recalling the file.

4.4 Menu FunctionsThe menu system is organised into four main groups File, Analysis, Image andSetup. This chapter describes all menu functions in detail.

4.4.1 File menuThe file menu contains all the functions concerned with the digital image and voicestorage, Open.., Save, Voice comment..., Delete image..., Directory... and Reportcomment... .

Figure 4:6 File menu.


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Open...This function is used to open or recall previously saved images from the disk. Thefunctions brings up a control box showing the name of the image being displayedand the directory in which the image file is stored. To select another image to bedisplayed, use the joystick up and down to change the selected image from thedirectory.

Figure 4:7 Open control box.

The index field after the image/directory name contains file order information.Example: Name G0112-12 12/23 represents the 12th image in a directory

containing 23 images.

Note that the measurement functions, colour scales and object parameters can bechanged since these are saved with the image and will be used when it is recalled.

To change the directory select Change dir by moving the joystick to the right. Thedirectories can then be changed by moving the joystick up and down.

SaveThis function will save the displayed image onto the PC-Card disk. Together withthe image all the current conditions like measurement function, colour scale, zoomfactor, values of the object parameters etc. will be saved to be used again when theimage is recalled. If the save function is activated on a recalled image , aconfirmation panel will appear on the screen.

Figure 4:8 Confirm; Image exist -> Create new or Overwrite.

If Create new is selected, the image on the screen will be stored in a new file (witha new automatically allocated name) on the disk. If Overwrite is selected, this willoverwrite the recalled image file on the disk..

The same function can be activated by pressing the S button for more than onesecond.


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If Voice comment is enabled (see Setup - Save options, Chapter 4.4.4) the voicedialogue will pop up on the screen. The user can now add a comment to the image(see Voice comment... below) or just press ↵ to store the image without a voicecomment.

Voice comment...The function is used to add a voice comment to an image.

When pressing the ↵ button the voice comment dialogue will be displayed on thescreen.

Figure 4:9 Voice comment dialogue.

Features in the Image voice comment function:• listen to a recorded comment, make a pause, and then continue.• record a new comment, make a pause, and then continue.• edit a recorded comment i.e. listen and/or add a comment at the end of the

recorded comment.• it is also possible to “overwrite” an existing recording.• add comments to an already recorded voice comment.

General operationAs long as the S button is depressed recording will proceed. Playback will proceedas long as the A button is depressed.

Normally when the ↵ button is depressed the image will be stored together with thenew comment. The camera will return to the status prior to the image voicecomment session, i.e. live or recalled image.

Possible cases when ↵ has been depressed:

• If no comment has been recorded the comment panel will be removed and nostorage will occur.


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• If a new comment has been recorded and the recalled image did not contain acomment. Pressing ↵ will restore the image together with the new comment.

• If a new comment has been recorded and the image is frozen. Pressing ↵ willremove the dialogue box and store the image together with the comment with anew filename.

If a new comment has been recorded and the recalled image already contains acomment. Pressing ↵ will result in a confirmation dialogue box being shown onthe screen.

The default selection in the confirmation panel is No. If No is selected andpressing ↵ dialogues will be removed an no storing will occur. If Yes is selectedthe old comment will be overwritten.

Possible scenarios when the C button has been depressed in the voice commentdialogue box:

• If no change has been made to the voice comment, the voice comment panelwill be removed.

• If the voice comment has been changed a confirmation panel shows up on thescreen.

Selecting No or the C button will remove the confirmation panel. Selecting Yesretain the voice comment dialogue box.

Voice comment info panel

This function will display a user prepared ASCII text file on the screen whenselecting Voice comment.

The function is enabled by selecting Voice comment. An ASCII text file namedVOICECMT.TXT must be located in the working/inspection directory or in theroot directory.If the file is placed in the root directory this function will be enabled independent ofthe selected working/inspection directory.

The camera displays the first 15 charachter in each row. A maximum of 9 rows isdisplayed. The first row is selected as the heading.


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Delete image...This function is used to delete previously saved images from the disk. The functionbrings up a control bar showing the name of the image being displayed and thedirectory in which it is stored. To select another image to be deleted move thejoystick up and down to change the selected image from the directory.

Figure 4:10 Delete Image control bar.

To change the directory move the joystick to the right. The directories can then bechanged by moving the joystick up and down.

To delete an image, select Del Image and press ↵. The image will be deleted afterselecting Yes and pressing ↵ in the confirmation dialogue box.

If the directory is empty it is possible to delete the directory. The dialogue boxitem Del Image is changed to Del Dir. Deleting the directory is done in the sameway as deleting an image (see above).

Directory...This function is used to change the working/inspection directory. To changedirectory move the joystick up or down until the selected directory is highlightedand the last image (alphabetical order) in the directory is shown on the screen. Bypressing the ↵ button the selection is made and the dialogue box is removed.

Figure 4:11 Change directory dialogue box.


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To create a new directory select the last item in the directory list Create new andpress the ↵ button. If you select Yes in the confirmation panel an automaticallynamed directory is created on your disk. This new directory is now your workingdirectory.

Report commentThis function is used to store a general report comment within an inspectiondirectory. The comment will be stored in a separate file under the presentinspection directory. The handling is similar to the Voice comment... function.

Report comment info panel

This function will display a user prepared ASCII text file on the screen whenselecting Report comment.

The function is enabled by selecting Report comment. An ASCII text file namedREPOTCMT.TXT must be located in the working/inspection directory or in theroot directory.If the file is placed in the root directory this function will be enabled independent ofthe selected working/inspection directory.

The camera displays the first 15 charachter in each row. A maximum of 9 rows isdisplayed. The first row is selected as the heading.

4.4.2 Analysis menuIn the analysis menu the desired measurement function can be set. Isotherm canalways be activated along with one of the functions Area, Spot or Profile. Theresults of a measurement function are presented in the result table located in the topright-hand corner of the screen.

Figure 4:12 Analysis menu


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An asterisk (*) in front of the menu item indicates that the measurement function isactive. By pressing the C button when the joystick text is displayed (e.g."Joystick:Spot pos C: Remove" ) the measurement function will be disabled.

Obj par...This function is used to manually set the object parameters Emiss, (emissivityfactor), Dist (distance), Tamb (ambient temperature) and RelHum (relativehumidity). Also included is the reference temperature Ref T. The function brings upa control box showing the different parameters.

The object parameters are described in Chapter 7, Theory of thermography.

Ref tempActivating this command by pressing ↵ will set the Ref temp equal to themomentary temperature of the active measurement function. The result table (∆)will show the difference between the measurement function temperature and thereference temperature. If the isotherm is enabled together with anothermeasurement function the isotherm value will always be used as the referencetemperature. It is also possible to manually set the Ref temp, see Obj par... above.

Note: To enable the Ref temp function, see chapter 4.4.4 Setup-Analysis Diff temp.

Example of use:Point the Area max function at a good phase of a power breaker and activate theRef temp command. This will set the reference temperature to the hottesttemperature of the good phase. Point the same area function at the faulty phase andread the increase in difference in temperature as the difference temperature (∆)under the Area max function.

SpotThe spotmeter function measures the centre temperature of the cross hair anddisplays the value in the result table. The position of the cross hair is controlled bythe movement of the joystick while the text "Joystick: Spot pos C: Remove" isshown in the bottom left-hand corner of the viewfinder. When the required spotposition has been set press the ↵ button to resume the normal function of thejoystick, i.e. focus/zoom.


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Area The area function measures either the max, min or average temperature within arectangle or circle area around the centre of the image. The result is indicated bythe Amin, Amax or Aavg text in the result table. The size of the area is controlledby the movement of the joystick in the following way while the text “Joystick: Areasize C:Remove” is shown in the viewfinder.

Joystick UP: Increases the rectangle height or circle radiusJoystick Down: Decreases the area height or circle radiusJoystick Left: Decreases the rectangle width or circle radiusJoystick Right: Increases the rectangle width or circle radius

Once the required area size has been set, press the ↵ button to resume the normalfunction of the joystick, i.e. focus/zoom.

The Area type (i.e. Box or Circle) and the Area function (i.e. Amin, Amax or Aavg)are selected in Setup-Analysis (See chapter 4.4.4).

Profile The profile function shows a horizontal or vertical temperature graph, dependingon the Analysis-setup setting (see chapter 4.4.4), marked by the profile line. Thetemperature of the cursor is indicated by the Cur text in the result table. Theposition of the profile and the cursor on the profile is controlled by the movementof the joystick while the text “Joystick: Prof pos C:Remove” is shown in thebottom left-hand corner of the viewfinder.

Once the required profile position has been set, press the ↵ button to resume thenormal function of the joystick, i.e. focus/zoom.


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Figure 4:13 Horizontal profile.

IsothermThe isotherm function colours all parts in the image which have the sametemperature as the selected isotherm temperature range. The isotherm type andcolour are selected in the Analysis-setup (see chapter 4.4.4).

The isotherm temperature is indicated by the Iso text in the result table and can bechanged by moving the joystick while the text “Joystick: Isotemp C.Remove” isshown. When the required isotherm temperature has been set press the ↵ button toresume the normal function of the joystick, i.e. focus/zoom.

When the Isotherm type is set to Intervalthe Isotherm width must be set to greaterthan zero. Otherwise the isotherm will not show up on the screen. . The width of theIsotherm can be set in the Setup-Analysis menu (see chapter 4.4.4). All valueswhich fall within the isotherm temperature range will be coloured with the selectedisotherm colour.


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4.4.3 Image menu

Figure 4:14 Image menu

Man adjust...This function is used to make a manual adjustment of the IR-image. After selectingthe function a control panel is presented on the screen. To select an item i.e. Level,Span, Range or Filter, move the joystick left/right. To change an item value, movethe joystick up/down.

Figure 4:15 Adjustment control panel.

Level: Sets the midpoint of the temperature span displayed in the image

Span: Sets the span of the temperatures displayed in the image

Temp range: The camera supports three different temperature ranges. If a filteris installed fivedifferent temperature ranges are available.The first three Temp ranges have the filter switched Off and the following twoswitched On.

Freeze / LiveThe function toggles the Freeze/Live status if the image. It has the same effect asdepressing the S button.

Auto adjustThe camera automatically optimises the parameter(s) Level, Level and span or Autopalette, see Setup-Image in chapter 4.4.4, for best image contrast and brightness.


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Auto adjust is a one time procedure which can be repeated if required. It has thesame effect as pressing on the A button.

Auto rangeThis function is similar to the Auto adjust function, with a additional Temp rangeoptimisation, i.e. if the an object, within the field of view, has higher temperaturethan the selected measurement range the camera automatically adjusts the range.

• Auto changing to a higher temperature range is done one step at a time, i.e.multiple execution of the Auto range function may be needed when optimising avery high temperature image.

• Auto changing to a lower temperature range is normally done in one step.

Auto Range can be accessed either from this menu or by pressing the A button formore than 1 second.

Image onlyThis function removes all on screen graphics (result table, data on image etc.). Bypressing ↵ or C button the screen is restored.

External image correctionThis function calibrates the pixel to pixel differences in the camera with thepresent image as reference, (compared to Auto adjust which uses the image of theinternal shutter as reference). This function is recommended to be used when thescene temperature is around 0°C or the ambient temperature around the camera isabove 35°C

When using this function point the camera at a completely uniformed temperatureobject and activate the function.

4.4.4 Setup menuContains all the functions for changing the camera setup parameters.

The camera is equipped with a non-volatile memory area that holds all setupparameters whilst the camera is switched off. The active measurement function(e.g. Spot) and working/inspection directory are also stored in the non volatilememory. When the camera is switched on it retains the same settings as thosebefore it was last switched off.


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Figure 4:16 Setup menu.

Analysis...The analysis setup defines the parameters used for the measurement functions (seeAnalysis menu 4.4.2). By pressing ↵, when "Analysis..." is highlighted in the Setuppull down menu, the "Setup -Analysis" dialogue box is displayed on the screen. Bymoving the joystick up/down the different dialogue box items are selected i.e.Isotherm type, Isotherm width, Isotherm colour, Area type, Area function, Profileand Diff temp. By moving the joystick left/right the item parameters will bechanged. When the ↵ button is pressed the parameters are stored and the dialoguebox is removed. If the clear button is pressed the dialogue box is removed withoutstoring any changed parameters.

Isotherm type:The isotherm types can either be Interval, Above or Below.

Isotherm width:The isotherm width is a temperature in the range 0.1 °C to 242 °C (or 0.2 °F to 436°F).

Isotherm colour:The isotherm colour can be selected as either Green, Black or White.

Area type:The different area types are Box and Circle.

Area function:There are three different area measurement functions for the selected area type.They are: Max, Min and Average.


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Profile:The profile measurement can either be Vertical or Horizontal.

Diff temp:Difference temperature is an On/Off function. If On is selected the result table willshow the difference between the actual measurement function temperature and theRef temp (See Analysis, chapter 4.4.2).

Image...The image setup defines the parameters used for the image adjustments (see Imagemenu, chapter. 4.4.3). By pressing ↵ when "Image..." is highlighted in the Setuppull down menu, the "Setup-Image" dialogue box is displayed on the screen. Bymoving the joystick up/down the different dialogue box items are selected i.e. Autoadjust, Image correction, Colour scales, Image mode, Saturation colour, Datafield, Data background and Scale. By moving the joystick left/right the itemparameters will be changed. When the ↵ button is pressed the parameters are storedand the dialogue box is removed. If the clear button (C) is pressed the dialoguebox is removed without storing any changed parameters.

Auto adjust:This parameter enables you to select the following choices: Level, Level and span,Auto palette.These mean that the auto adjust function (see Image menu, chapter 4.4.3) useseither Level, Level and span or Auto palette for adjusting the image for optimalbrightness and contrast. The Auto palette function spreads out the colours of thescale to give good contrast on both hot-spots and the background simultaneously.

Image correction:This parameter determines the image correction mode, which can either be Auto orExternal. If Auto is selected External image correction cannot be made in the Imagemenu (see chapter 4.4.3).

Colour scales:There are eight different palette selections: Grey, Grey inverted, Grey 10, Grey 10inverted, Rainbow, Rainbow 10, Iron and Iron 10.


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Image mode:

There are three image mode selections: Normal, Still or Fast.Normal mode is used in most condition monitoring applications.Still mode can be used if you need to improve the camera performance even furthercompared to the normal operation. A special type of filtering is employed, whatrequires that the object or camera to be stationery or moving very slowly duringinspection. A tripod mounted camera is recommended.In the Fast mode the camera is optimised for capturing fast moving objects.

Saturation colour:Saturation colour is an On/Off function. If On is selected the areas that containtemperatures outside the present level/span settings are coloured with thesaturation colours. The saturation colours contain an "overflow" colour and an"underflow" colour.

There is also a third red saturation colour that marks everything saturated by thedetector indicating that the range should probably be changed.

Data field:This parameter determines the amount of data/information that will be shown onthe screen. There are four levels: Reduced, Normal, Extended and None.

Figure 4:17 Extended data presentation.

In Reduced mode, only the lower row is displayed. In Normal mode the lower andmiddle rows are displayed. In Extended mode all three rows are displayed.

• The lower row contains information on the date, time, emissivity and zoomfactor.

• The middle row contains filter (optional) setting (NOF=Off or HT=HighTemperature=On), lens used5:(FOV 20, FOV 5, FOV 10, or FOV 40; e.g. FOV20 = 20° Field Of View)/7:(FOV 24 or FOV 12 ̧e.g. FOV 24 = 24° Field ofview)/ and selected temperature range.

• The upper row contains information on the current directory, ambienttemperature, relative humidity and object distance.


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Data backgroundThe background of the data can be selected as Transparent or Solid.

ScaleA scale (colour bar) can be selected by setting this parameter On.

Local adapt...By pressing the ↵ button when "Local adapt..." is highlighted in the Setup pulldown menu, the "Setup-Locals" dialogue box is displayed on the screen. Bymoving the joystick up/down the different dialogue box items are selected i.e. Tempunit, Dist unit, Language, Date format and Time format. By moving the joystickleft/right the item parameters will be changed. When the ↵ button is pressed theparameters are stored and the dialogue box is removed. If the clear button (C) ispressed the dialogue box is removed without storing any changed parameters.

Temp unit: °C (Celsius) or °F (Fahrenheit).

Distance unit: Metres or Feet.

Language: English or ................menu language.

Date format: MM/DD/YY, DD/MM/YY or YY-MM-DD.

Time format: HH:MM:SS, HH:MM:SS PM or HH.MM.SS.

Save options...By pressing ↵ button when "Save options..." is highlighted in the Setup pull downmenu, the "Setup-Save options" dialogue box is displayed on the screen. Bymoving the joystick up/down the different dialogue box items are selected i.e.Image storage, Voice comment and Image naming.. By moving the joystickleft/right the item parameters will be changed. When the ↵ button is pressed theparameters are stored and the dialogue box is removed. If the clear button (C) ispressed the dialogue box is removed without storing any changed parameters.

Image storage:If this parameter is selected as Single one image will be stored on the disk afterpressing the S button for an extended period of time. If Continuous is selected,images will be stored as fast as possible, for as long as the S button is depressed.


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Voice comment:If this parameter is selected as Yes the Voice dialogue box (see chapter 4.4.1) willshow up on the screen every time an image storage operation is made. This functiongives the user a chance to add a voice comment to the image before storing theimage on disk. If Continuous mode is selected, as in "Image Storage" above, thisfunction is ignored.

Image naming:If Use date is selected, the automatic generation of image names will be based oncurrent date. If Use dir is selected, the automatic generation of image names will bebased on the first five characters of the current inspection directory in use. (seechapter 4.3.3)

Date & Time...By pressing the ↵ button when "Date & Time..." is highlighted in the Setup pulldown menu, the "Setup-Date/Time" dialogue box is displayed on the screen. Bymoving the joystick up/down the different dialogue box items are selected i.e.Year, Month, Day, Hour and Minute. By moving the joystick left/right the itemparameters will be changed. When the ↵ button is pressed the parameters are storedand the dialogue box is removed. If the clear button (C) is pressed the dialoguebox is removed without storing any changed parameters.

System Info...By pressing the ↵ button when "System Info..." is highlighted in the Setup pulldown menu, the "System information" panel is displayed on the screen.By moving the joystick left/right another information panel is selected. There are 3different panels. When the ↵ button or the clear button (C) is pressed theinformation panels are removed.

Cooler off/onIf only recalled images are to be viewed the stirling cooler can be switched off.By pressing the ↵ button when "Cooler off" is highlighted in the Setup pull downmenu, the cooler will be switched ON. If "Cooler on" is displayed, pressing thisbutton will switch the cooler OFF. As long as the cooler is OFF a "Critical info"box is displayed on the screen, informing the user that the cooler is off, whilst theimage is LIVE or FROZEN. Recalled images hide this box.


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5. Battery systemThe battery system consists of a battery belt with up to four batteries and a fastcharger.

5.1 Battery beltThe batteries are discharged in pairs giving an operation time of more than twohours per battery pair. When “battery low” is indicated in the camera it is time toswitch to the Second battery pair by flipping the switch (See figure) on the batterybelt. The first battery pair can now be charged while the camera is running on thesecond battery pair and vice versa. To avoid restarting of the camera, the switchconnects the new battery pair before disconnecting the old battery pair.

Figure 5:1 Battery belt.

When the left side of the switch is pressed the two batteries to the left areconnected.

Switch


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5.2 Battery chargingConnect the power cable between the power outlet and the back of the charger.The charger automatically switches voltages and accepts 100- 240 V AC.

Place the batteries to be charged in the slots of the charger. The batteries willbe “fast charged” one by one in the order the batteries are inserted intothe charger.

The status is indicated by the three sets of LED’s in the following way.

Yellow The battery is waiting to be charged either because another battery is being fast charged or because the battery is too cold to be charged.

Blinking yellow The battery is being charged

Green The battery is charged and ready for use.

After approx. one hour the green light will light up while the yellow is still blinking indicating that the battery is charged to 90 % capacity and it is ready tobe used.

After approx. one hour more the yellow LED willstop blinking and the battery is now charged to100%.

Blinking Red The battery is faulty and cannot be charged.


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5.3 Useful notes on the battery systemThere is no risk of overcharging or damaging already charged batteries. If acharged battery is inserted into the charger the charging will start but be abortedafter approx. 5 minutes when the charger senses that the battery is full.

If the battery is colder than 15° C the charging cannot be started at once but needsto be heated up first. This process will be indicated by a yellow light. If the batteryis too warm the charging will not start.

Whilst it is not recommended, the camera will still operate if only one battery isused instead of a pair. However, one battery will yield slightly less than half theoperating time of a battery pair.

Fully capacity from new metal hydride batteries is obtained after approx. 5 chargeand discharge cycles.

Batteries are not normally delivered pre-charged.

The batteries will self discharge at the rate of approx. 2 % per day while beingstored. It is therefore advisable to charge batteries each time before use.

Metal hydride batteries do not develop the same memory effect as NiCd batteriessometimes do. It is therefore unnecessary to discharge the batteries completelybefore charging.


5-4

Figure 5:2 Battery charger.


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6. Thermal measurement techniques

6.1. IntroductionThe Thermovision 550 measures and images the emitted infrared radiation froman object. The fact that radiation is a function of object surface temperature makesit possible for the camera to calculate and display this temperature.

However, the radiation measured by the camera does not only depend on theobjects temperature but is also a function of the emissivity. Radiation alsooriginates from the surroundings and is reflected in the object. The radiation fromthe object and the reflected radiation will also be influenced by the absorption ofthe atmosphere.

To measure temperature accurately, it is therefore necessary to compensate for theeffects of a number of different radiation sources. This is done on-lineautomatically by the Thermovision 550. The following object parameters musthowever, be supplied for the camera.

Figure 6:1 Radiation contributions to the general measurement situation.

Object Atmosphere

Thermovision 550

Radiation emittedby the object

Radiation emitted by the surroundingsand reflected in the object

Radiation emittedby the atmosphere


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6.2 EmissivityThe most important object parameter to set correctly is the emissivity which, inshort, is a measure of how much radiation is emitted from the object compared tothat if it was a perfect blackbody.

Normally, object materials and surface treatments exhibit emissivities ranging fromapproximately 0.1 to 0.95. A highly polished (mirror) surface falls below 0.1, whilean oxidised or painted surface has much higher emissivity. Oil-based paint,regardless of colour in the visible spectrum, has an emissivity over 0.9 in theinfrared. Human skin exhibits an emissivity close to 1.

Non-oxidised metals represent an extreme case of almost perfect opacity and highspecular reflectivity, which does not vary greatly with wavelength. Consequently,the emissivity of metals is low - only increasing with temperature. For non-metals,emissivity tends to be high, and decreases with temperature.

Typical emissivities for a variety of common materials are listed in figure 6:2.table.. The values are meant to be used only as a guide and can vary depending onmany different factors.


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Metals and their oxides Temp. (°C) Emissivity(e)Aluminium:

foil (bright) 20 0.04weathered 20 0.83 - 0.94

Copper:polished 100 0.05heavily oxidised 20 0.78

Iron:cast, oxidised 100 0.64sheet, heavily rusted 20 0.69 - 0.96

Nickel:electroplated, polished 20 0.05

Stainless Steel (type 18-8):polished 20 0.16oxidised 60 0.85

Steel:polished 100 0.07oxidised 200 0.79

Other materials Temp. (°C) Emissivity(e)Brick: common red 20 0.93Carbon candle soot 20 0.95Concrete:dry 35 0.95Glass: chemical ware 35 0.97Oil: lubricating 17 0.87

film thickness 0.03 mm 20 0.27film thickness 0.13 mm 20 0.72thick coating 20 0.82

Paint, oil:average of 16 colours 20 0.94

Paper: white 20 0.07 - 0.90Plaster 20 0.86 - 0.90Rubber: black 5 20 0.95Skin: human 32 0.98Soil: dry 20 0.92

saturated with water 20 0.95Water:

distilled 20 0.96frost crystals -10 0.98snow -10 0.85

Wood: planed oak 20 0.90

Figure 6:2 Emissivities of common materials


6-4

6.3 Finding the emissivity of an objectUsing a thermocoupleSelect a reference point and measure its temperature using a thermocouple. Alterthe emissivity until the temperature measured by the Thermovision 550 agrees withthe thermocouple reading. This is the emissivity value of the reference object.However, the temperature of the reference object must not be too close to theambient temperature for this to work.

Reference emissivityA tape or paint of a known emissivity should be put onto the object. Measure thetemperature of the tape/paint using the camera, setting emissivity to the correctvalue. Note the temperature. Alter emissivity, until the area with the unknownemissivity adjacent to the tape/paint has the same temperature reading. Theemissivity value can now be read off. The temperature of the reference object mustnot be too close to the ambient temperature for this to work either.

6.4 Ambient temperatureThis parameter is used to compensate for the radiation reflected in the object andthe radiation emitted from the atmosphere between the camera and the object.

If the emissivity is low, the distance very long and the object temperature relativelyclose to that of the ambient it will be important to set and compensate for theambient temperature correctly.

6.5 Distance and relative humidityThe distance is the distance between the object and the front lens of the camera.

This parameter is used to correct for the fact that radiation is being absorbedbetween the object and the camera and the fact that transmittance drops withdistance.

The camera can also compensate for the fact that the transmittance is heavilydependent on the relative humidity of the atmosphere. To do this set the relativehumidity to the correct value. For short distances and normal humidity the relativehumidity can normally be left at a default value of 50 %.


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7. Theory of thermography

7.1 IntroductionThe subjects of infrared radiation and the related technique of thermography arestill new to many who are in a position to make use of a Thermovision® camera. Inthis section the theory behind thermography will be given.

7.2 The Electromagnetic SpectrumThe electromagnetic spectrum is divided arbitrarily into a number of wavelengthregions, called "bands", distinguished by the methods utilised to produce and detectthe radiation. There is no fundamental difference between radiation in the differentbands of the electromagnetic spectrum. They are all governed by the same laws andthe only differences are those due to differences in wavelength.

Figure 7:1 The Electromagnetic Spectrum

Thermography makes use of the infrared spectral band. At the short-wavelengthend the boundary lies at the limit of visual perception, in the deep red. At the long-wavelength end it merges with the 'microwave' radio wavelengths, in the millimetrerange.


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The infrared band is often further subdivided into four smaller bands, theboundaries of which are also arbitrarily chosen. They include: the "near infrared"(0.75 - 3 µm), the "middle infrared" (3-6 µm), the "far infrared" (6-15 µm) and the"extreme infrared" (15-100 µm). Although the wavelengths are given in µm(micrometres), other units are often still utilised to measure wavelength in thisspectral region, e.g. microns(µ), nanometres (nm) and Ångströms (Å).The relationships between the different wavelength measurements is

10,000 Å = 1,000 nm = 1µ = 1 µm

7.3 Blackbody RadiationA blackbody is defined as an object which absorbs all radiation that impinges on itat any wavelength. The apparent misnomer “black” relating to an object emittingradiation is explained by Kirchhoff’s Law, which states that a body capable ofabsorbing all radiation at any wavelength is equally capable in the emission ofradiation.

The construction of a blackbody source is very simple in principle. The radiatecharacteristics of an aperture in an isotherm cavity made of an opaque absorbingmaterial represents almost exactly the property of a blackbody. A practicalapplication of the principle to the construction of a perfect absorber of radiationconsists of a box that is light tight except for an aperture in one of the sides. Anyradiation which then enters the hole is scattered and absorbed by repeatedreflections so only an infinitesimal fraction can possibly escape. The blacknesswhich is obtained at the aperture is nearly equal to a blackbody and almost perfectfor all wavelengths.

By providing such an isothermal cavity with a suitable heater it becomes what istermed a “cavity radiator”. An isothermal cavity heated to a uniform temperaturegenerates blackbody radiation, the characteristics of which are determined solely bythe temperature of the cavity. Such cavity radiators are commonly utilised assources of radiation in temperature reference standards in the laboratory forcalibrating thermographic instruments, such as Thermovision® 550 for example.

If the temperature of blackbody radiation increases to over 525°C, the sourcebegins to be visible so that it appears to the eye no longer black. This is theincipient red heat temperature of the radiator, which then becomes orange or yellowas the temperature increases further. In fact, the definition of the so-called “colourtemperature” of an object is the temperature to which a blackbody would have to beheated to have the same appearance.


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Now consider three expressions that describe the radiation emitted from ablackbody.

a) Planck’s law. Max Planck was able to describe the spectral distribution of theradiation from a blackbody by means of the following formula:

Wλb = 2πhc2

x10-6[Watts/m2µm]

λ5(ehc/λkT-1)

where

Wλb = the blackbody spectral radiant emittance at wavelength λ

c = the velocity of light = 3 x 108 m/sec.

h = Planck’s constant = 6.6 x 10-34 Joule sec.

k = Boltzmann’s constant = 1.4 x 10-23 Joule/K.

T = the absolute temperature (K) of a blackbody.

λ = wavelength (m)

Note: The factor 10-6 is used since spectral emittance in the curves is expressedin Watts/m2µm. If the factor is excluded, the dimension will be Watts/m2m.

Planck’s formula, when plotted graphically for various temperatures, produces afamily of curves. Following any particular Planck curve, the spectral emittance iszero at λ = 0, then increases rapidly to a maximum at a wavelength λmax and afterpassing it approaches zero again at very long wavelengths. The higher thetemperature, the shorter the wavelength at which maximum occurs.


7-4

Figure 7:2 Blackbody spectral radiant emittance according to Planck’s law,plotted for various absolute temperatures.

b) Wien’s displacement law. By differentiating Planck’s formula with respect to λand finding the maximum, we have:

λmax=2898

[µm]T

This is Wien’s formula, which expresses mathematically the common observationthat colours vary from red to orange or yellow as the temperature of a thermalradiator increases. The wavelength of the colour is the same as the wavelengthcalculated for λmax. A good approximation of the value of λmax for a givenblackbody temperature is obtained by applying the rule-of-thumb (3000K). Thus, avery hot star such as Sirius (11,000K), emitting bluish-white light, radiates with thepeak of spectral radiant emittance occurring within the invisible ultravioletspectrum, at wavelength 0.27 µm.


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The sun (approx. 6,000K) emits yellow light, peaking at about 0.5 µm in the middleof the visible light spectrum.

At room temperature (300K) the peak of radiant emittance lies at 9.7 µm, in the farinfrared, while at the temperature of liquid nitrogen (77K) the maximum of thealmost insignificant amount of radiant emittance occurs at 38 µm, in the extremeinfrared wavelengths.

c) The Stefan-Boltzmann law. By integrating Planck’s formula from λ = 0 to λ =×, we obtain the total radiant emittance (Wb) of a blackbody:

Wb = σT4 [Watts/m2]

where

σ = the Stefan-Boltzmann constant = 5.7 x 10-8 Watts/m2.

This is the Stefan-Boltzmann formula, which states that the total emissive power ofa blackbody is proportional to the fourth power of its absolute temperature.Graphically, Wb represents the area under the Planck curve for a particulartemperature. It can be shown that the radiant emittance in the interval l = 0 to lmax isonly 25 percent of the total, which represents about the amount of the sun’sradiation which lies inside the visible light spectrum.


7-6

Figure 7:3 Planckian curves plotted on semi-log scales from 100 to 1000K. Thedotted line represents the locus of maximum radiant emittance at each temperatureas described by Wien’s displacement law.

Using the Stefan-Boltzmann formula to calculate the power radiated by the humanbody, at a temperature of 300K and an external surface area of approx. 2m2, weobtain 1 kilowatt. This power loss could not be sustained if it were not for thecompensating absorption of radiation from surrounding surfaces, at roomtemperatures which do not vary too drastically from the temperature of the body –or, of course, the addition of clothing.


7-7

7.4 Non-blackbody emittersSo far, only blackbody radiators and blackbody radiation have been discussed.However, real objects almost never comply with these laws over an extendedwavelength region - although they may approach the blackbody behaviour incertain spectral intervals. For example, white paint appears perfectly “white” in thevisible light spectrum, but becomes distinctly “grey” at about 2 µm, and beyond 3µm it is almost “black”.

Figure 7:4 Spectral radiant emittance and spectral emissivity of three types ofradiators.


7-8

There are three processes which can occur that prevent a real object from actinglike a blackbody: a fraction of the incident radiation α may be absorbed, a fractionρ may be reflected, and a fraction τ may be transmitted. Since all of these factorsare more-or-less wavelength dependent, the subscript λ is used to imply the spectraldependence of their definitions. Thus:

The spectral absorptance αλ = the ratio of the spectral radiant power absorbed byan object to that incident upon it.

The spectral reflectance ρλ = the ratio of the spectral radiant power reflected by anobject to that incident upon it.

The spectral transmittance τλ = the ratio of the spectral radiant power transmittedthrough an object to that incident upon it.

The sum of these three factors must always add up to the whole at any wavelength,so we have the relation

αλ + ρλ + τλ = 1

For opaque materials τλ = 0, and the relation simplifies to

αλ + ρλ = 1

Another factor, called the emissivity, is required to describe the fraction ε of theradiant emittance of a blackbody produced by an object at a specific temperature.Thus, we have the definition:

The spectral emissivity ελ = the ratio of the spectral radiant power from an objectto that from a blackbody at the same temperature and wavelength.

Expressed mathematically, this can be written as the ratio of the spectral emittanceof the object to that of a blackbody as follows:

ε λλο

λ

=W

W b

Generally speaking, there are three types of radiation source, distinguished by theways in which the spectral emittance of each varies with wavelength.


7-9

a) A blackbody, for which el = e = 1.

b) A greybody, for which el = e = constant less than 1.

c) A selective radiator, for which e varies with wavelength.

According to Kirchhoff’s Law, for any material the spectral emissivity and spectralabsorptance of a body are equal to any specified temperature and wavelength. Thatis: ελ = αλ .

From this we obtain, for an opaque material (since αλ + ρλ = 1):

ελ + ρλ = 1

For highly polished materials ελ approaches zero, so that for a perfect reflectingmaterial (= a perfect mirror) we have

ρλ = 1

For a greybody radiator, the Stefan-Boltzmann formula becomes

W = εσT4 [Watts/m2]

This states that the total emissive power of a greybody is the same as a blackbodyat the same temperature reduced in proportion to the value of ε from the greybody.


7-10

7.5 Infrared semi-transparent materialsConsider now a non-metallic, semi-transparent body – for simplicity, in the form ofa thick flat plate of plastic material. When the plate is heated, radiation generatedwithin its volume must work its way toward the surfaces through the material inwhich it is partially absorbed. Moreover, when it arrives at the surface, some of it isreflected back into the interior. The back-reflected radiation is again partiallyabsorbed, but some of it arrives at the other surface, through which it mostlyescapes; part of it is reflected back again. Although the progressive reflectionsbecome weaker and weaker they must all be added up when the total emittance ofthe plate is sought. When the resulting geometrical series is summed, the effectiveemissivity of a semi-transparent plate is obtained as

ελ = (I-ρλ)(I-τλ)

I-ρλτλ

This formula represents a generalisation of Kirchhoff’s law, which reduces whenthe plate becomes opaque (τλ = 0) to the single form

ελ = 1 - ρλ

This last relation is a particularly convenient one, because it is often easier tomeasure reflectance than to measure emissivity directly.


8-1

8. Technical specifications

8.1 Thermovision 550 camera

Object temperature -20 °C to 250 °C (-4 °F to 480 °F) measurement range: Up to 1500 °C (2200 °F) with standard filter

Measurement accuracy: ± 2 % of range or ± 2 °C

Thermal sensitivity: < 0.1 °C

Field of view (H x V): 20° x 15° (interchangeable lenses available as accessories)

Detector type: Focal Plane Array (FPA), 320x240 pixels

Spectral range: 3.6 - 5 micrometer, built-in SRX-filter withcut-on at 3.6 micrometer

IR Spectral filter: One optional filter, controlled from menu

Video output: Standard VHS or S-VHS12 bit digital serial output (optional)

Viewfinder: Colour LCD (TFT)

PC-Card drive: One slot for type II or type III PC-cards. Either FLASH Cards or Hard Disks (ATA-compatible) can be used

Image storage: Full dynamics, 12-bit digital storage.Capacity for a 170 MByte PC-Card is 700 images including voice comment (optional) of 30 sec./image.

Maximum image size: 215 Kbyte (incl. voice)


8-2

Battery system: Four rechargeable, metal hydride batteries mounted in battery belt.

Operating time: More than 6 hours using the battery belt

Environmental temp range: Operating -15 °C to 50 °C ( 5 °F to 120 °F) Storage -40 °C to 70 °C (-40 °F to 160 °F)

Enclosure: Metal CasingProtection: IP 54 (IEC 529)

Tripod Mount: 1/4”-20

Weight: 2 Kg

Size: 220x132x140 mm


8-3

8.2 Lenses

The following table shows the horizontal image size (FOV) at various distancesbetween camera and object for the available standard lenses.Also the geometrical resolution of the camera is indicated by the IFOV value.

Note that the 20° lens is always built into the camera.

Objectdistance: 0.1 m 0.4 m 1.5 m 3 m 6m 30m 100m

5° lensFOV 0.5* 2.6 9 (m)IFOV 1.6 8.2 27 (mm)

10° lensFOV 0.27* 0.54 1.1 5.3 18 (m)IFOV 0.8 1.7 3.4 17 55 (mm)

20° lensFOV 0.14* 0.54 1.1 2.1 11 36 (m)IFOV 0.4 1.6 3.4 6.6 34 110 (mm)

40° lensFOV 0.07* 0.3 1.1 2.2 4.4 22 72 (m)IFOV 0.2 0.9 3.4 6.8 14 68 226 (mm)

*At close focus


8-4

8.3 Input/output (connectors)

Figure 8:1 Pin configuration

12 V socket:Pin1 RS-232, TxD (Output Data)2 RS-232, RxD (Input Data)3 S-Video Y (Optional 12 bit digial output).4 S-Video C (Optioanl 12 bit digital output).5 S-Video Ground6 Not used7 Power in 11-16 V8 Ground Power9 Ground Power10 Power in 11-16 V

If extension cables are used they should be designed to have a maximum cableresistance of less than 0.18 ohm. The Power pins 7 and 10 and the ground pins 8and 9 should always be used in parallel.


8-5

Headset socketPin1 Headphone, +. Impedance >350 ohm. Max swing 2.3 Vpp2 Head phone, -.3 Microphone, +. Electorate type, Phantom feed 5 V DC, 1 mA, Max

swing 30 mVpp4 Microphone, -.5 Not used

Video socketComposite video either PAL or NTSC SMB type connector 75 ohm cable.


8-6

8.4 Battery charger

Input: 100-240 V, 50WFrequency: 50/60 HzOutput: 11-18V DC, 1.8 AWeight: 0.7 KgMax output: 36 WattSize: 230x150x72 mm

CE certified

8.5 Power supply (Optional)

Input: 100-240 V, 1.3 AFrequency: 50/60 HzOutput: 13.5 V DCWeight: 0.7 KgMax output: 55 WattSize: 200x96x60 mmCable length: 1.2 m

CE certifiedUL and CSA approved

HEADQUARTERS: AGEMA Infrared Systems AB, Box 3, S-182 11 DANDERYD, Sweden Tel. +46 (0)8 753 25 00 Fax. +46 (0)8 753 23 64FRANCE: AGEMA Infrared Systems SARL, 18 Rue Hoche, B.P.81, F-92134 ISSY LES MOULINEAUX Tel. +33 (0)1 41 33 97 97 Fax. +33 (0)1 47 36 18 32GERMANY: AGEMA Infrared Systems GmbH, Siemensstraße 20, D-64289 DARMSTADT Tel. +49 (0)61 51 70 84 1 Fax. +49 (0)61 51 70 81 27ITALY: AGEMA Infrared Systems, Div. of Spectra-Physics SRLCentro Direzionale Lombardo, Palazzo E/1, Via Roma 108 I-20060 CASSINA DE´PECCHI (MI) Tel. +39 (0)2 953 02 498 Fax. +39 (0)2 953 02 594SWEDEN: AGEMA Infrared Systems AB, Sales Department,Box 3, S-182 11 DANDERYD Tel. +46 (0)8 753 27 50 Fax. +46 (0)8 755 07 52UNITED KINGDOM: AGEMA Infrared Systems Ltd.,Arden House LEIGHTON BUZZARD, Beds. LU7 7DD Tel. +44 (0)1525 375660 Fax. +44 (0)1525 379271UNITED STATES: AGEMA Infrared Systems, 550 County Avenue SECAUCUS, NJ 07094 Tel. +1 201-867-5390 Fax. +1 201-867-2191

www.agema.com

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