REPLICATING HUMAN VISION FOR ACCURATE TESTING OF AR/VR DISPLAYS Presented By Eric Eisenberg February 22, 2018

Transcription

1 REPLICATING HUMAN VISION FOR ACCURATE TESTING OF AR/VR DISPLAYS Presented By Eric Eisenberg February 22, 2018

2 Light & Color Automated Visual Inspection Global Support

3 TODAY S AGENDA Challenges in Near-Eye Display Measurement The Trouble with Current Methods Replicating Human Vision: High-Resolution Imaging Aperture Size Aperture Position Capturing the Full FOV AR/VR Measurement Solution Question & Answer Session 3

4 CHALLENGES IN NED MEASUREMENT CONSIDERATIONS FOR DISPLAYS VIEWED CLOSE-UP 4

5 MARKET GROWTH: AR/VR The AR/VR headset market is expected to reach 81.2 million units by 2021, with a CAGR of 56.1%. - IDC Research Source: 5

6 WHAT IS THE CONCERN? Market trends indicate a need to measure more displays that are: Viewed extremely close up Viewed with a wide field of view (immersive) Viewed within head-mounted devices (goggles and headsets) 6

7 COMMON APPLICATIONS Virtual Reality (VR) Augmented Reality (AR) Mixed Reality (MR) 7

8 DISPLAYS VIEWED CLOSE UP Projections are magnified for wider, immersive field of view (FOV), but cause more noticeable defects Uniformity issues, dead pixels, line defects, inconsistency from eye to eye Near-Eye Displays More pixels per eye increases realism, but require higher-res measurement device 8

9 DISPLAYS VIEWED WITH WIDE FOV With display in fixed position, horizontal FOV leveraged for immersion, but requires wide FOV optics for complete evaluation Embedded Displays Display testing from position of the human eye while capturing full horizontal angular FOV Some AR/VR devices replicate human binocular FOV (approx. 120 degrees), requiring equivalent measurement FOV 9

10 SAMPLE HEADSET FOVS Source: 10

11 DISPLAYS IN HEAD-MOUNTED DEVICES Measuring what the user sees means getting inside the headset Need a more compact optical system Head-Mounted Displays Need to position a measurement device at the designed location of the human eye in the headset to capture the same FOV intended to be viewed by the user through the headset lenses 11

12 UNIQUE MEASUREMENT CRITERIA Luminance and color uniformity Image clarity (Slant Edge Contrast/MTF) Image distortion Focus uniformity Field of view measurements 12

13 THE TROUBLE WITH CURRENT METHODS 13

14 EXISTING SOLUTION OPTIONS Display measurement performed by: 1. Machine Vision Cameras: Not appropriate for absolute luminance & color measurement. 2. Limited Resolution: Low-resolution sensors, <16 megapixels. 3. Standard Optics: E.g., traditional 35mm lens options with internal aperture. 4. Custom Optics: Not productized; expensive and long lead time. 5. Made-in-House Test Software: Limited capability, support, and scalability. 14

15 MACHINE VISION CAMERAS Not appropriate for absolute luminance and color measurement: No luminance & Cx,Cy coordinates Unlike imaging colorimeters, do not offer CIE-matched color filters for accurate luminance and chromaticity values. Not calibrated Unlike Radiant systems, do not feature advanced factory calibrations for color, luminance, linearity, and image correction for highest accuracy. Low Signal-to-Noise Ratio (SNR) Unlike Radiant systems, are not optimized for the lowest noise possible with electronics design and thermoelectrically-cooled sensors to increase dynamic range and ensure repeatability of measurements. 15

16 LIMITED RESOLUTION Low-Resolution Sensors: Inadequate for pixeldense displays May miss dot, particle, pixel, and other small defects Incapable of MTF measurement 16

17 STANDARD OPTICS Regardless of the camera: Size of standard optical hardware prevents positioning measurement system within headset Aperture of standard optics causes occlusion of the image through goggles Field of view of standard optics is not wide enough to cover FOV of most NEDs 17

18 OBSTRUCTED FIELD OF VIEW 18

19 CUSTOM OPTICS Customizing a lens solution means: Increased expense Long lead time Minimal scalability to future applications Minimal product support through project lifecycle 19

20 MADE-IN-HOUSE TEST SOFTWARE In-house software means: Increased expense Increased time to implement Minimal scalability to future applications Limited extendibility to other display test applications Minimal product support 20

21 TECHNICAL ADVANTAGES DISPLAY TEST SOLUTIONS THAT REPLICATE HUMAN VISION 21

22 TESTING ALL NEAR-EYE DISPLAY TYPES Virtual Reality (VR) Augmented Reality (AR) Mixed Reality (MR) Experience Projection View Channel Display Type Optical Design Immersive Reflective Monocular LCD Opaque See-through Transmissive Binocular LCOS Bird Bath Transflective Bi-Ocular OLED Free Space Emissive DLP Light guide Laser MEMs Waveguide 22

23 ADVANTAGES OF IMAGING Imaging Photometers and Colorimeters Efficiency: Detect all meaningful variations across displays in a single image Scope: Capture the entire FOV in a single image 23

24 ACCOMPLISH MULTIPLE MEASUREMENTS AT ONCE Uniformity Contrast Pixel/line defects Image location/size Distortion Modulation Transfer Function (MTF) Measurement sequences performed on a single image by software paired with imaging solution 24

25 ADVANTAGES OF RESOLUTION High-resolution CCD Imaging Ensures: Detail: Capture multiple CCD pixels per display pixel Precision: With more CCD pixels captured, improve detection of pixel- and subpixel-level defects in the display 25

26 CAPTURE ALL POTENTIAL DEFECTS Final Analysis Test Image 26

27 REPLICATE HUMAN EYE CHARACTERISTICS Ensure aperture (entrance pupil) receives equivalent light (captures equivalent detail) as the human eye Simulate human eye pupil size (2-8 mm) Ensure aperture is positioned to capture full display FOV Simulate human eye position in headset (at eye lens) Typical camera lenses have aperture inside. For near-eye applications, this distance results in occlusion of the image and prevents capturing the full display FOV Aperture position and lens FOV combine to capture full horizontal display FOV Cover approximate FOV of binocular human vision ( ) 27

28 IMPORTANCE OF APERTURE SIZE Simulates the human eye pupil size Replicating human pupil size captures equivalent light (equivalent detail) from the display as the human eye Using a smaller aperture, the imaged display would appear to be sharper, with fewer/less severe aberrations than what the human observes Using a larger aperture, the imaged display would appear to have extra/more severe aberrations than what the human observes 28

29 IMPORTANCE OF APERTURE POSITION Simulate the human eye position within AR/VR headsets In standard camera lenses, aperture is inside lens. Lens hardware puts distance between entrance pupil and designed human eye position Distance causes occlusion of the display by the headset hardware At the eye position, the aperture can capture the full FOV without occlusion Lens Internal aperture 29

30 IMPORTANCE OF APERTURE POSITION Simulate the human eye position within AR/VR headsets In standard camera lenses, aperture is inside lens. Lens hardware puts distance between entrance pupil and designed human eye position Distance causes occlusion of the display by the headset hardware At the eye position, the aperture can capture the full FOV without occlusion Lens Front aperture 30

31 UNOBSTRUCTED FIELD OF VIEW 31

32 UNOBSTRUCTED FIELD OF VIEW 32

33 KNOT-HOLE EXAMPLE Entrance pupil far from opening Entrance pupil at opening 33

34 CAPTURING THE FULL FOV 120 binocular 34

35 AR/VR MEASUREMENT SOLUTION FOR NEAR-EYE DISPLAY TESTING IN HEADSETS 35

36 RADIANT S AR/VR SOLUTION Measure near-eye displays (NED) in AR/VR goggles and headsets 36

37 IMAGING WITH ADVANCED OPTICS Pair AR/VR lens with Radiant ProMetric 16- and 29- megapixel imagers Imaging for measurement efficiency High-Resolution for precise pixel-level defect detection Full FOV for capturing the scope of NEDs in one image 37

38 AR/VR LENS Aperture (entrance pupil) located on front of lens 3.6 mm aperture Wide field of view (FOV): 120 horizontal Factory Distortion Calibration 38

39 CALIBRATION FOR LENS EFFECTS Factory Distortion Calibration: Before distortion calibration After distortion calibration 39

40 TRUETEST SOFTWARE Full suite of TrueTest display tests Standard Display Tests: Luminance, Chromaticity, Contrast, Uniformity, Defects TT-ARVR Module Tests: Slant Edge Contrast (MTF), Image Distortion, Field View (Device FOV), x,y position in degrees ( ) 40

41 STANDARD DISPLAY TESTS Point-Based Uniformity Pixel and Line Defects Mura Detection and JND 41

42 PRESERVING IMAGE CLARITY Slant Edge Contrast/MTF MTF measurement based on ISO Modulation = value that describes resolution + contrast Modulation Transfer Function (MTF) determines contrast at different spatial frequencies Testing is done using projections of horizontal and vertical pairs of black and white lines 42

43 MTF SLANT EDGE CONTRAST Measures the ratio between black and white areas on a contrasting slant pattern. 43

44 MTF LINE PAIR ALGORITHM Line pair algorithms quickly measure contrast between vertical and horizontal line pairs 44

45 CHARACTERIZING HEADSET EFFECTS Image Distortion Characterizing distortion from the device or headset Pattern used in test 45

46 PRESERVING THE INTENDED EXPERIENCE Field View Reporting the horizontal, vertical, and diagonal AR/VR display FOV. 46

47 OTHER SOFTWARE ADVANTAGES Spatial x,y positions given in degrees ( ) Locating POI on-screen in terms of angular FOV Software test sequencing Run multiple tests in sequence Apply multiple software tests to a single image API Device Interface Integrate with AR/VR device to control display images Software video pattern generator using standard video output (e.g., HDMI) 47

48 SOFTWARE TEST SEQUENCING 48

49 AR/VR DISPLAY TEST SOLUTION + + AR/VR Lens ProMetric Imaging Colorimeter or Photometer (16- or 29-megapixel options) TrueTest Software (TT-ARVR module optional) 49

50 SUMMARY Growth in embedded and AR/VR markets requires testing new displays viewed close-up, from a fixed position, within headset hardware. Standard display measurement equipment lacks the optical specifications to capture displays within headsets to evaluate the full display FOV. Radiant s AR/VR Solution is the only solution with unique optical components that replicate the human pupil size (3.6 mm) and position within AR/VR goggles and headsets to capture the full display FOV to 120 degrees. 50

51 THANK YOU! Questions? Contact