REPLICATING HUMAN VISION FOR ACCURATE TESTING OF …...Feb 22, 2018 · Display testing from...

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

3Radiant Vision Systems | A Konica Minolta Company

© Radiant Vision Systems, LLC.

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



CHALLENGES IN NED MEASUREMENTCONSIDERATIONS FOR DISPLAYS VIEWED CLOSE-UP



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



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)



COMMON APPLICATIONS

Mixed Reality (MR)Augmented Reality (AR)Virtual Reality (VR)



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



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



SAMPLE HEADSET FOVS

Source: http://vrglassesheadsets.com/vr-headset-comparisons-field-of-view

http://vrglassesheadsets.com/vr-headset-comparisons-field-of-view



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



UNIQUE MEASUREMENT CRITERIA

• Luminance and color

uniformity

• Image clarity (Slant Edge

Contrast/MTF)

• Image distortion

• Focus uniformity

• Field of view measurements



THE TROUBLE WITH CURRENT METHODS



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.



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.



LIMITED RESOLUTION

Low-Resolution Sensors:

▪ Inadequate for pixel-dense displays

▪ May miss dot, particle, pixel, and other small defects

▪ Incapable of MTF measurement



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



OBSTRUCTED FIELD OF VIEW



CUSTOM OPTICS

Customizing a lens solution means:

▪ Increased expense

▪ Long lead time

▪ Minimal scalability to future applications

▪ Minimal product support through project lifecycle



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



TECHNICAL ADVANTAGESDISPLAY TEST SOLUTIONS THAT REPLICATE HUMAN VISION



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



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



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



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



CAPTURE ALL POTENTIAL DEFECTS

Test Image

Final Analysis



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°)



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



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



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



UNOBSTRUCTED FIELD OF VIEW



“KNOT-HOLE” EXAMPLE

Entrance pupil far from opening Entrance pupil at opening



CAPTURING THE FULL FOV120° binocular



AR/VR MEASUREMENT SOLUTIONFOR NEAR-EYE DISPLAY TESTING IN HEADSETS



RADIANT’S AR/VR SOLUTION

Measure near-eye displays (NED) in AR/VR goggles and headsets



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



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



CALIBRATION FOR LENS EFFECTS

Factory Distortion Calibration:

Before distortion calibration After distortion calibration



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 (°)



STANDARD DISPLAY TESTS

Point-Based Uniformity Pixel and Line Defects Mura Detection and JND



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



MTF SLANT EDGE CONTRAST

Measures the ratio between black and white areas on a contrasting slant pattern.



MTF LINE PAIR ALGORITHM

Line pair algorithms quickly measure contrast between vertical and horizontal line pairs



CHARACTERIZING HEADSET EFFECTS

Image Distortion

▪ Characterizing distortion from the device or headset

Pattern used in test



PRESERVING THE INTENDED EXPERIENCE

Field View

▪ Reporting the horizontal, vertical, and diagonal AR/VR display FOV.



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)



SOFTWARE TEST SEQUENCING



AR/VR DISPLAY TEST SOLUTION

+

TrueTest Software(TT-ARVR module optional)

AR/VR Lens

+

ProMetric® Imaging Colorimeter or Photometer(16- or 29-megapixel options)



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.

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

THANK YOU!

mailto:[email protected]

REPLICATING HUMAN VISION FOR ACCURATE TESTING OF …...Feb 22, 2018 · Display testing from...

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