AUTOMATED HEAD-UP DISPLAY MEASUREMENT · CAPTURING AND QUANTIFYING MULTIPLE DATA POINTS. Radiant Vision Systems ... REDUCE SETUP & MEASUREMENT TIME Spot-based measurement requires

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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

• Line-Pairing Algorithm

• Full Field-of-View Imaging

• Multi-Test Sequencing Software

• Software Tests: TT-HUD Module



2 – 29 MP CCD / 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 (WIP)§ “Optical Metrology for

Automotive HUD”

§ 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 (a)

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



LINE-PAIRING ALGORITHMSQUANTIFYING 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 D

MD

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-PAIRING ALGORITHM

Line-pairing 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, Cx, Cy, 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



TESTS IN TRUETEST™ TT-HUD MODULE

Test Color? Pattern(s)

ANSI Brightness Photopic White 255, or desired pattern

Uniformity Color White 255

Diagonal Checkerboard Photopic Diagonal Checkerboard

Distortion Grid Photopic Grid (Dot and Line)

Warping Photopic Grid

Sequential Contrast Photopic Black, White; Checkerboard, Inverse Checkerboard

Eye Box Photopic Target

MTF Line Pair Photopic Line pairs (1 pixel, 2 pixel, etc)

Image Sticking Photopic Black, or low grey level



ANSI BRIGHTNESS

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



UNIFORMITYCreates NxN grid on image, and reports out average luminance of each grid point, as well as additional statistics (min, max, difference, etc.)



DIAGONAL CHECKERBOARD CONTRAST

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.



DISTORTION GRID

Reports out the position of each grid point, and in addition can measure the distance between points and pass/fail on this value.



DISTORTION LINE GRID

Analysis finds the points where lines of a test image intersect and reports their location. Can also pass or fail a device based on the spacing of the intersection points of the pattern.



WARPING

Test image has a white square directly in the center of the pattern. The analysis locates the white squares and reports the distance the center square to every other square.



SEQUENTIAL CONTRAST

Takes measurement of Black, and White patterns. Compares luminance values of the entire image. Computes contrast ratio.



EYEBOX

Looks for a continuous shape with no breaks. The line width is specified in the analysis for pass/fail.



MTF LINE PAIRS

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) or a default can be used.



IMAGE STICKING

A checkerboard pattern is used for the initial burn in, then a low grey level image is used. The analysis takes multiple images of the display over a user-specified time interval. The images are analyzed to determine the strength of the burn in pattern.



ENABLING FULLY-AUTOMATED TESTING

HUD

VIRTUAL IMAGE

CAMERA IN THE “EYE BOX”

SERIES OF TEST IMAGESFOR EACH HUD TESTED



SUMMARY

ü SAE J1757-2 standard will specify measurement devices for HUD evaluation

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

ü Electronically-controlled lenses for simplified image location

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

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

ü 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.

RadiantVisionSystems|AKonicaMinoltaCompanyRadiantVisionSystems|AKonicaMinoltaCompanyQuestions? Contact [email protected]

THANK YOU!

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AUTOMATED HEAD-UP DISPLAY MEASUREMENT · CAPTURING AND QUANTIFYING MULTIPLE DATA POINTS. Radiant Vision Systems ... REDUCE SETUP & MEASUREMENT TIME Spot-based measurement requires