Radiant Vision Systems | A Konica Minolta Company Radiant Vision Systems | A Konica Minolta Company Presented By Eric Eisenberg | February 22, 2018 REPLICATING HUMAN VISION FOR ACCURATE TESTING OF AR/VR DISPLAYS
Radiant Vision Systems | A Konica Minolta CompanyRadiant Vision Systems | A Konica Minolta CompanyPresented By Eric Eisenberg | February 22, 2018
REPLICATING HUMAN VISION FOR ACCURATE TESTING OF AR/VR DISPLAYS
Global SupportAutomated Visual InspectionLight & Color
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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
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CHALLENGES IN NED MEASUREMENTCONSIDERATIONS FOR DISPLAYS VIEWED CLOSE-UP
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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:https://www.twice.com/product/vr-ar-headset-market-poised-growth-66176
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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)
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COMMON APPLICATIONS
Mixed Reality (MR)Augmented Reality (AR)Virtual Reality (VR)
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DISPLAYS VIEWED CLOSE UP
Near-Eye Displays
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
More pixels per eye increases
realism, but require higher-res
measurement device
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DISPLAYS VIEWED WITH WIDE FOV
With display in fixed position,
horizontal FOV leveraged for
immersion, but requires wide FOV
optics for complete evaluation
▪ 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
Embedded Displays
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SAMPLE HEADSET FOVS
Source: http://vrglassesheadsets.com/vr-headset-comparisons-field-of-view
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DISPLAYS IN HEAD-MOUNTED DEVICES
Head-Mounted Displays
Measuring what the user sees means
getting inside the headset
• Need a more compact optical system
▪ 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
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UNIQUE MEASUREMENT CRITERIA
• Luminance and color
uniformity
• Image clarity (Slant Edge
Contrast/MTF)
• Image distortion
• Focus uniformity
• Field of view measurements
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THE TROUBLE WITH CURRENT METHODS
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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.
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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.
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LIMITED RESOLUTION
Low-Resolution Sensors:
▪ Inadequate for pixel-dense displays
▪ May miss dot, particle, pixel, and other small defects
▪ Incapable of MTF measurement
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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
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OBSTRUCTED FIELD OF VIEW
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CUSTOM OPTICS
Customizing a lens solution means:
▪ Increased expense
▪ Long lead time
▪ Minimal scalability to future applications
▪ Minimal product support through project lifecycle
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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
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TECHNICAL ADVANTAGESDISPLAY TEST SOLUTIONS THAT REPLICATE HUMAN VISION
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Mixed Reality (MR)Augmented Reality (AR)
TESTING ALL NEAR-EYE DISPLAY TYPES
Virtual Reality (VR)
Projection View Channel Display Type Optical DesignExperience
Monocular
Binocular
Bi-Ocular
Reflective
Emissive
Transmissive
Transflective
Immersive
See-through
Free Space
Light guide
Waveguide
Opaque
Bird Bath
LCD
OLED
LCOS
DLP
Laser MEMs
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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
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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
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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
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CAPTURE ALL POTENTIAL DEFECTS
Test Image
Final Analysis
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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
(114-120°)
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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
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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 Internal
aperture
Lens
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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 Front
aperture
Lens
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UNOBSTRUCTED FIELD OF VIEW
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UNOBSTRUCTED FIELD OF VIEW
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“KNOT-HOLE” EXAMPLE
Entrance pupil far from opening Entrance pupil at opening
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CAPTURING THE FULL FOV120° binocular
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AR/VR MEASUREMENT SOLUTIONFOR NEAR-EYE DISPLAY TESTING IN HEADSETS
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RADIANT’S AR/VR SOLUTION
Measure near-eye displays (NED) in AR/VR goggles and headsets
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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
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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
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CALIBRATION FOR LENS EFFECTS
Factory Distortion Calibration:
Before distortion calibration After distortion calibration
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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 (°)
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STANDARD DISPLAY TESTS
Point-Based Uniformity Pixel and Line Defects Mura Detection and JND
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PRESERVING IMAGE CLARITY
Slant Edge Contrast/MTF▪ MTF measurement based on
ISO 12233
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
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MTF SLANT EDGE CONTRAST
Measures the ratio between black and white areas on a contrasting slant pattern.
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MTF LINE PAIR ALGORITHM
Line pair algorithms quickly measure contrast between vertical and horizontal line pairs
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CHARACTERIZING HEADSET EFFECTS
Image Distortion
▪ Characterizing distortion from the device or headset
Pattern used in test
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PRESERVING THE INTENDED EXPERIENCE
Field View
▪ Reporting the horizontal, vertical, and diagonal AR/VR display FOV.
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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)
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SOFTWARE TEST SEQUENCING
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AR/VR DISPLAY TEST SOLUTION
+
TrueTest Software(TT-ARVR module optional)
AR/VR Lens
+
ProMetric® Imaging Colorimeter or Photometer(16- or 29-megapixel options)
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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.
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THANK YOU!