ps_1.0.0 -tutorial (il) - orthophoto_dem

8/10/2019 PS_1.0.0 -Tutorial (IL) - Orthophoto_DEM

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Tutorial (Intermediate level):

Orthophoto and DEM generation

with Agisoft PhotoSan Pro !"#"#

Add PhotosTo add photos selectAdd Photos"""command from the $or%flowmenu or clickAdd Photosbutton located on $or%spaetoolbar.

In theAdd Photosdialog browse the source folder and select files to be processed. Click Open

button.

Load Camera Positions At this step coordinate system for the future model is set using camera positions.

Note: If camera positions are unknown this step could be skipped. The align photos procedure,

however, would take more time in this case.

Open &round 'ontrolpane using the corresponding command from the iewmenu.

Click Importbutton on the &round 'ontrolpane toolbar and select file containing camera

positions information in the Opendialog.

The easiest way is to load simple character-separated file !.t"t# that contains "- and y-

coordinates and height for each camera position camera orientation data, i.e. pitch, roll and yaw

values, could also be imported, but the data is not obligatory#.

InImport 'Sdialog indicate the delimiter according to the structure of the loading file and select

the row to start loading from. $ote that % character indicates a commented line that is not counted

while numbering the rows. Indicate for the program what parameter is specified in each column

through setting correct column numbers in the 'olumnssection of the dialog. Check your settings in

the sample data field inImport 'Sdialog.

Click Openbutton. The data will be loaded into the &round 'ontrolpane.

Import EI*&round 'ontrolpane toolbar button can also be used to load camera positions

information if &'I( meta-data is available.


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Then click on the Settingsbutton in the &round 'ontrolpane and in the &round 'ontrol

Settingsdialog select corresponding coordinate system from the list.

Click O) and camera positions will be marked inModel iewusing their geographical

coordinates*


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Align PhotosAt this stage +hotocan refines the camera position for each photo and builds the point cloud

model.

electAlign Photoscommand from the $or%flowmenu.

et the following recommended values for the parameters in theAlign Photosdialog*

Accuracy:+ighlower accuracy setting can be used to get the rough camera positions in

the shorter time#

Pair preselection: &round 'ontrol in case camera positions are unknown &eneri

preselection mode can be used#

Constrain features by mask:Disa,ledEna,ledin case any areas has been masked prior

to processing#

Point limit:-####

Click O.button to start photo alignment.


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Place Markers arkers are used to optimie camera positions and orientation data, which allows for better model

reconstruction results.

To generate accurate orthophoto at least /0 1 /2 ground control points 3C+# should be

distributed evenly within the area of interest to be processed.

To be able to follow guided marker placement approach that would be faster and easier# you needto reconstruct geometry first.

elect/uild Meshcommand from the $or%flowmenu and specify following parameters in the

/uild Meshdialog*

Click O) button.

Then, when the geometry is built it usually takes a few seconds to reconstruct mesh based on thesparse point cloud#, open a photo where a 3C+ is visible in +hoto 4iew double-clicking on its icon in

the +hoto pane. 5oom in to locate the 3C+ on the photo and place a marker in the corresponding

point of the image using Create arker command from the photo conte"t menu available on

right-click on the opened photo in the corresponding position*


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elect the marker on the &round 'ontrolpane. Then filter images inPhotospane using

*ilter ,0 Mar%ersoption in the conte"t menu available by right-clicking on the markers label in the

$or%spaepane.

$ow you need to check the marker location on every related photo and refine its position if

necessary to provide ma"imum accuracy. Open each photo where the created marker is visible. 5oom

in and drag the marker to the correct location while holding left mouse button. 6epeat the described

step for every 3C+. (inally, import marker coordinates from a file. Click Importbutton on the &round 'ontrol

pane toolbar and select file containing 3C+ coordinates data in the Open dialog. The easiest way is to

load simple character-separated file !.t"t# that contain markers name, "-, y- coordinates and height.


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In Import C4 dialog indicate the delimiter according to the structure of the file and select the

row to start loading from. $ote that % character indicates a commented line that is not counted while

numbering the rows. Indicate for the program what parameter is specified in each column through

setting correct column numbers in the Columns section of the dialog.

Check your settings in the sample data field in Import C4 dialog*

Click O) button. The data will be loaded into the 3round Control pane.

Optimize Camera Alignment To achieve higher accuracy in calculating camera e"ternal and internal parameters and to correct

possible distortion e.g. 7bowl effect8 and etc.# optimiation procedure should be run. This step is

especially recommended if the ground control point coordinates are known almost precisely several

centimeters accuracy# marker based optimiation procedure#.

Click the ettings button in the 3round Control pane and in the 3round Control ettings

dialog select corresponding coordinate system from the list according to the 3C+ coordinates data.

et the following values for the parameters in easurement accuracy section*


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Camera accuracy:/0

Marker accuracy:0.002 The marker accuracy is recommended to be set at 0 value if the

real marker accuracy is within 0.09 m. In this case +hotocan will assume

that markers coordinates are known e"actly, which can help to obtain more

accurate results.#

Scale bar accuracy:0.00/

Proection accuracy:0./

!ie point accuracy::

Click O) button.

On the 3round Control pane uncheck all photos and check the markers to be used in optimiation

procedure. The rest of the markers that are not taken into account can serve as control points to

evaluate the optimiation results.

Click Optimie button on the 3round Control pane toolbar.

elect camera parameters you would like to optimie. Click O) button to start optimiation

process.

Set "ounding "o#

;ounding bo" is resiable and rotatable with the help of 6esie 6egion and 6otate

6egion tools from the Toolbar.

$mportant: The red-colored side of the bounding bo" indicates the plane that would be treated as

ground plane and has to be set under the model.


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"uild %ense Point Cloud;ased on the estimated camera positions the program calculates depth information for each

camera to be combined into a single dense point cloud.

elect/uild Dense 'loudcommand from the $or%flowmenu.

et the following recommended values for the parameters in theAlign Photosdialog*

&uality: Medium higher Crop

instruments located on the Toolbar.


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"uild MeshAfter dense point cloud has been reconstructed it is possible to generate polygonal mesh model

based on the dense cloud data.

elect/uild Meshcommand from the $or%flowmenu.

et the following recommended values for the parameters in the /uild &eometr0dialog*

Surface type:+eight *ield

Source data:Dense loud

Polygon count:Medium ma"imum number of faces in the resulting model. The values

indicated ne"t to +igh1Medium12ow preset labels are based on the number of

points in the dense cloud#

$nterpolation:Ena,led

Click O.button to start building geometry.


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'dit (eometryometimes it is necessary to edit geometry before building te"ture atlas and e"porting the model.

?nwanted faces could be removed from the model. (irstly, you need to indicate the faces to be

deleted using selection tools from the toolbar. elected areas are highlighted with red color in the

odel 4iew. Then, to remove the selection use =elete election button on the Toolbar or =&@ key#

or use Crop election button on the Toolbar to remove all but selected faces.

If the overlap of the original images was not sufficient, it may be re


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"uild !e#tureThis step is not really needed in the orthophoto e"port workflow, but it might be necessary to

inspect a te"tured model before e"porting it or it might be useful for precise marker placement.

elect/uild Te3turecommand from the $or%flowmenu.

et the following recommended values for the parameters in the/uild Te3turedialog*

Mapping mode:Orthophoto

"lending mode:Mosai

!e#ture size)count:/D9width E height of the te"ture atlas in pi"els#

'nable color correction:disa,led the feature is useful for processing of data sets with

e"treme brightness variation, but for general case it could be left unchecked to save

the processing time#

Click O.button to start building te"ture.


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(enerate Orthophoto

electE3port OrthophotoF E3port 4PE&1TI**1P5&command from*ile menu.

et the following recommended values for the parameters in the E3port Orthophoto

dialog*

Proection type:&eographi

Proection:by default the proGection set in the &round 'ontrol Settingsis used

"lending mode:Mosai

'nable color correction:disa,led the feature is useful for processing of data sets withe"treme brightness variation, but for general case it could be left unchecked to save

the processing time#

Pi#el size:ma"imum effective resolution is shown by default

Split in blocks:!#### "!####if the e"ported area is large it is recommended to enable

Split in /lo%sfeature, since the memory consumption is rather high at e"porting

stage#

*egion:set the boundaries of the modelBs part that should be proGected and presented as

orthophoto.

ClickE3port"""button and then specify target file name and select type of the e"ported file

e.g. 3eoTI((#. Click Savebutton to start orthophoto generation.


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(enerate %'M

electE3port DEMF &"port 3eoTI((>;I@>'H5 command from*ilemenu.

et the following recommended values for the parameters in theE3port DEMdialog*

Proection type:&eographi

Proection:by default the proGection set in the &round 'ontrol Settingsis used

Crop in+alid %'M:check this option to crop the regions with unreliable elevation data,

since they are visible on less than two source photosPi#el size:you can increase the effective resolution compared to the default value

Split in blocks:!#### " !#### if the e"ported area is large it is recommended to enable

Split in ,lo%sfeature, since the memory consumption is rather high at e"porting

stage#

*egion:set the boundaries of the modelBs part that should be presented as =&.

ClickE3port"""button and then specify target file name and select type of the e"ported file

e.g. 3eoTI((#. Click Savebutton to start =& generation.

ps_1.0.0 -tutorial (il) - orthophoto_dem

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