automated head-up display measurement · radiant vision systems | a konica minolta company...

Radiant Vision Systems | A Konica Minolta CompanyRadiant Vision Systems | A Konica Minolta Company

System Benefits for SAE-Standard Optical Performance Evaluation of HUDs

AUTOMATED HEAD-UP DISPLAY MEASUREMENT

2Radiant Vision Systems | A Konica Minolta Company

© Radiant Vision Systems, LLC.

TODAY’S TOPICS

• SAE Standards for Head-Up Displays

• SAE J1757-2

• Measurement Requirements

• Technology to Enable Automation:

• Electronically Controlled Lens

• Modulation Transfer Function (MTF)

• Full Field-of-View Imaging

• Multi-Test Sequencing Software

• Software Tests: TT-HUD Module



2 – 43 MP Sensor / Cooled / Temp. Stabilized

CIE Matched Color Filters

Electronic ND Filter Selection (colorimeter)

Electronic Lenses

On-Camera Calibration Data

USB & Ethernet Control

On-camera Touch Control (colorimeter)

• Auto-Lens Recognition• Electronic Zoom control• Electronic Aperture

selection• Auto-selection of

Calibration Data

IMAGING COLORIMETERS/PHOTOMETERS



SAE STANDARD HUD MEASUREMENTBACKGROUND AND REQUIREMENTS



HUD MEASUREMENT STANDARDS

Radiant has worked with

SAE Committee to define

new HUD Standard

▪ SAE J1757-2

▪ “Optical System HUD for

Automotive”

▪ Imaging photometers

implemented into the

standard as a primary

solution for HUD testing



REQUIREMENTS FOR SAE STANDARD MEASUREMENT DEVICES

Optical meter camera

▪ Measure luminance, chromaticity, uniformity

▪ NIST-traceable

▪ Example: Photometer

Distance meter

▪ Measure geometrical distance, direction, angle, distortion

▪ Example: Smart Camera



KEY HUD MEASUREMENT CHALLENGES

• Virtual image location and size

• Image resolution and contrast accuracy

• Number of tests and parameters per test image

• Enabling production-level automated measurement



USING AN ELECTRONICALLY CONTROLLED LENSGAUGING VIRTUAL IMAGE SIZE AND LOCATION



Is the virtual image projected at the right location and at the correct size?

HUD

LOOK DOWN ANGLE ()

PROJECTION DISTANCE

SIZE

VIRTUAL IMAGE



VIRTUAL IMAGE

PROJECTION DISTANCE = FOCAL DISTANCE

DEPTH OF FOCUS (DOF)

• Convert focal distance to “real distance” units

• Using focal distance, and virtual image size, the distance of the projected image can be output automatically by software

MEASURING PROJECTION DISTANCE



OPTIMIZING FOCUS



OPTIMIZING FOCUS

Out of Focus Better Focus Best Focus

Notice: Increasing slope on cross section plot (corresponding to decreasing blue region

(between 10% and 90% of max grey value). Increasing focus bar (orange)



Calibrated cameras

provide absolute distance

measurements

Electronically controlled

lenses determine

projected image plane

▪ Remove human

calculation, error

▪ Reduce time to set up

measurements

CALCULATING ABSOLUTE MEASUREMENTS

f1

f2



Calibrated cameras

provide absolute distance

measurements

Electronically controlled

lenses determine

projected image plane

▪ Remove human

calculation, error

▪ Reduce time to set up

measurements

CALCULATING ABSOLUTE MEASUREMENTS



DEPTH OF FOCUS



MODULATION TRANSFER FUNCTION (MTF)QUANTIFYING MODULATION FOR RESOLUTION AND CONTRAST OF PROJECTIONS



HUD PROJECTOR (DLP) STRUCTURE

HUD

VIRTUAL IMAGE

CAMERA IN THE “EYE BOX”

DLP STRUCTURE

HUD Optics

DLP Optics

DM

D

HUD Electronics

Source Image

Projected Image

Picture Generating Unit (PGU)

HUD Box



PRESERVING IMAGE CLARITY

DMD

Micro-mirror array



TESTING FOR MODULATION

Modulation = value that describes resolution + contrast

Modulation Transfer Function (MTF) determines the level of spatial frequency between contrasting areas

Testing is done using projections of horizontal and vertical pairs of black and white lines



LINE-PAIR ALGORITHM

Line-pair algorithms quickly measure modulation between vertical and horizontal line pairs



FULL FIELD-OF-VIEW IMAGINGCAPTURING AND QUANTIFYING MULTIPLE DATA POINTS



REDUCE SETUP & MEASUREMENT TIME

Spot-based measurement requires multiple test points

Image-based measurement captures all data at once



ACCOMPLISH MULTIPLE MEASUREMENTS AT ONCE

Required measurements for SAE J1757-1:

▪ Uniformity

▪ Contrast

▪ Pixel count resolution

▪ Location / Size

▪ Ghosting

▪ Distortion / Alignment

▪ Modulation Transfer Function (MTF) Measurement sequences performed on a single

image by software paired with imaging solution



OBTAIN DATA BASED ON CONTEXT



INTRA-CHARACTER UNIFORMITY

Spot meter takes single-spot measurements at defined points.

Imaging enables software to measure entire symbol at once.



• Quickly determine, Lv; x,y; u’,v’; pixel count; and much more.

• Run specific user-based pass/fail criteria against each analysis requirement

INTER-CHARACTER UNIFORMITY



PIXEL RESOLUTION OF SYMBOLS



CONTRAST



GHOSTING



DISTORTION



TESTING FOR GHOSTING & DISTORTION

Test Pattern Measurement Image



MULTI-TEST SEQUENCING SOFTWAREAUTOMATING TEST AND MEASUREMENT



PRODUCTION-LEVEL MEASUREMENT



SOFTWARE TEST SEQUENCING



FULL SET OF TESTS INCLUDED IN TT-HUD™



EXAMPLE SEQUENCE FROM TT-HUD



ANSI BRIGHTNESS

The ANSI Brightness test averages the measured brightness of an image at the ANSI-9 points and compares these values against various Pass/Fail criteria.



UNIFORMITY

The Uniformity test Creates NxN grid on image, and reports out average luminance of each grid point, as well as additional statistics (min, max, difference)



SEQUENTIAL CONTRAST

The Sequential Contrast Analysis takes measurement of Black and White patterns. Compares luminance values within defined region. Computes contrast ratio.



EYEBOX TEST: OVERVIEW

Pass/Fail Parameters:- Min Contour Width (sensor pixels)

- If the width of the Contour (box around the edge of the target) is below this value, the test fails. The test also fails if there is a break anywhere in the contour.

The Eyebox test uses a target with a black background and a white, continuous line around the edge, and an optional cross in the middle

The analysis evaluates if this contour is unbroken. This tells the user that the entire eyebox is visible from that location of the Photometer or Colorimeter



EYEBOX TEST: PASS



EYEBOX TEST: FAIL (BROKEN)



EYEBOX TEST: FAIL (MISSING SIDE)



DISTORTION DOT GRIDThe Distortion Dot Grid analysis finds and reports out the position of each grid point.

Pass/Fail Criteria:- Total number of dots- Min Row Spacing- Max Row Spacing- Min Column Spacing- Max Column Spacing



DISTORTION LINE GRID

The Distortion Line Grid analysis finds the points where lines of a test image intersect and reports their location.

Pass/Fail Criteria:- Total number of dots- Min Row Spacing- Max Row Spacing- Min Column Spacing- Max Column Spacing



WARPING

The Warping Test Image has an array of evenly spaced dots. The analysis locates these white dots and reports their distance the center dot.

No Pass/Fail Criteria



GHOSTING: OVERVIEW

The Ghosting Analysis measures the Ghosting Target (white dots on a black background)

The analysis finds the location of the original dot (parent) and the location of the corresponding ghost and reports the distance. This analysis can currently analyze images with ONE ghost.

The ghost images can be connected to the original dot, or separated.

Pass/Fail Parameters:- Max distance (displacement) between

parent dot, and ghost

- Minimum Luminance Ratio ghost/parent

- Maximum Luminance Ratio ghost/parent

- Minimum number of displacement failures to report failure



GHOSTING: NO GHOST

Result: None Found



GHOSTING: SEPARATED GHOST

Reports out the luminance ratio (ghost/parent) and displacement distance between parent and Ghost image for each dot.



GHOSTING: CONNECTED GHOST

Reports out the luminance ratio (ghost/parent) and displacement distance between parent and Ghost image for each dot.



DIAGONAL CHECKERBOARD CONTRAST

The Diagonal Checkerboard Analysis places detectors on the black and white diamonds, reports the luminance values, calculates average black and white luminance, and reports ratio between the average black and white luminance.

Pass Fail Criteria:Minimum Contrast Ratio



MTF LINE PAIRS

The MTF Line Pairs test measures the MTF of the line pairs in the image, reporting out the contrast of each region. The regions can be user defined (as shown).

Pass/Fail Criteria:- Max Contrast Limit- Min Contrast Limit



ENABLING FULLY-AUTOMATED TESTING

HUD

VIRTUAL IMAGE

CAMERA IN THE “EYE BOX”

SERIES OF TEST IMAGESFOR EACH HUD TESTED



SUMMARY

✓ SAE J1757-2 standard specifies measurement devices for HUD evaluation

✓ HUD measurement can be most efficiently met using systems with:

✓ Electronically controlled lenses for simplified image location

✓ Built-in software algorithms for calculating Modulation Transfer Function (MTF) for visual image resolution and contrast

✓ Imaging capability and multi-test sequencing software for meeting the maximum measurement criteria at once

✓ Using these systems can enable fully-automated HUD measurement for application in production



Working closely with world class brands and manufacturers to deliver creative visual inspection solutions that improve

quality, reduce costs, and increase customer satisfaction.

Radiant Vision Systems | A Konica Minolta CompanyRadiant Vision Systems | A Konica Minolta CompanyQuestions? Contact [email protected]

THANK YOU!

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automated head-up display measurement · radiant vision systems | a konica minolta company...

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