Color Camera Optical Testing for XYZ Color and Raw Resolution
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Solution Overview
Problem
Standard imaging colorimeters are too large to easily scan the Eye Motion Box (EMB) of Near Eye Displays (NED) systems, and color cameras degrade resolution due to demosaicing algorithms like deBayering.
Innovation Solution
Use an off-the-shelf color camera to measure color uniformity and resolution by converting its output to XYZ color space using a conversion matrix generated from colorimeter measurements and overcoming deBayering effects through mathematical operations on a raw green channel image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard imaging colorimeter is used to measure color uniformity and resolution, then measurement accuracy is improved, but device size becomes too large to easily scan the Eye Motion Box of Near Eye Displays
Solution Approach 1:
The patent uses a color camera to capture images of the optical system, creating a digital copy of the visual output. This allows measurement of color uniformity and resolution through image processing rather than direct physical measurement, enabling the use of a compact camera instead of a bulky colorimeter while maintaining measurement capability
Solution Approach 2:
The patent replaces the mechanical scanning system of a traditional colorimeter with a digital imaging approach using a color camera. The camera captures the entire Eye Motion Box area in a single frame, eliminating the need for mechanical movement and reducing device size while maintaining measurement accuracy through computational methods
2Ease of operation
If a standard color camera is used to measure optical properties, then device size and ease of operation are improved, but resolution measurement accuracy deteriorates due to demosaicing algorithms
Solution Approach 1:
The patent extracts only the green channel data from the color camera's Bayer filter output, ignoring the red and blue channels. This extraction approach avoids the need for demosaicing algorithms that would otherwise interpolate and degrade resolution, allowing direct use of the green channel data for accurate resolution measurement
Solution Approach 2:
The patent changes the measurement approach by working directly with raw sensor data in the green channel rather than processing through full color demosaicing. This parameter change in the data processing method preserves the original spatial resolution information while still enabling color uniformity measurement through the green channel intensity variations
Data Source
AI summary
A device, system, and method are provided for processing an output of a color camera, such that the color camera may be used to measure color uniformity and resolution of an optical system. The processing includes converting an output of the color camera into an XYZ color space using a conversion matrix. The conversion matrix is generated by capturing color images and colorimeter measurements of three different wavelength ranges of light. The processing also includes overcoming the deBayering effect of the color camera to measure a resolution of the optical system using an optical test target displayed by the optical system. The optical test target has a uniform appearance along a direction of homogeneity. The resolution is determined based on a one-dimension image generated by performing a mathematical operation along the direction of homogeneity.