Display Color Calibration via MacAdam Ellipse Zones
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Solution Overview
Problem
Aeronautical display devices face challenges in maintaining consistent colorimetric and photometric performance, especially when replacing screens, due to the vast number of possible color and luminance levels, which existing methods struggle to accurately correct without excessive measurements and storage requirements.
Innovation Solution
The method involves measuring and calibrating a limited number of colorimetric control triplets, calculating correction vectors, and applying these corrections in real-time to ensure that displayed colors fall within the MacAdam ellipse, thereby achieving sufficient precision without perfect color correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individualized correction is applied to each color level, then colorimetric precision is improved, but measurement quantity and storage requirements become excessively large
Solution Approach 1:
The patent segments the color correction problem by dividing the 16.7 million color levels into groups represented by MacAdam ellipses. Instead of correcting each individual color level, the system defines correction zones (ellipses) in color space and determines corrections only at representative points within each zone, dramatically reducing the number of measurements and storage requirements while maintaining perceptual color accuracy.
Solution Approach 2:
The patent transforms the correction approach by changing from precise numerical color value correction to geometric zone-based correction using MacAdam ellipses. This parameter change allows the system to work with spatial regions in color space rather than discrete color levels, reducing complexity while preserving human visual perception accuracy.
2Measurement precision
If perfect color correction is applied, then colorimetric accuracy is improved, but complexity of correction system increases
Solution Approach 1:
The patent applies partial correction by recognizing that perfect color accuracy is unnecessary for human perception. By using MacAdam ellipses to define acceptable color variation zones, the system applies corrections only to the extent needed to keep displayed colors within perceptually indistinguishable ranges, simplifying the correction system while maintaining sufficient accuracy.
Solution Approach 2:
The patent introduces MacAdam ellipses as an intermediary concept between precise colorimetric measurements and human visual perception. These ellipses serve as mediators that translate complex color accuracy requirements into simple geometric zones, allowing the correction system to operate with reduced complexity while maintaining perceptual accuracy.
3Reliability
If display screens are replaced to maintain performance, then reliability is improved, but maintaining colorimetric consistency becomes more difficult
Solution Approach 1:
The patent creates a universal calibration method based on MacAdam ellipses that can be applied to any display screen regardless of manufacturer, model, or age. This universal approach allows consistent colorimetric calibration across different display devices, ensuring reliable image quality consistency when screens are replaced without requiring device-specific correction data.
Data Source
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AI summary
The technical field of the invention is that of methods for adjusting the photometric and colorimetric parameters of a display device composed of luminous colored dots. The method according to the invention makes it possible to calibrate the display device against a reference display device. The method consists of establishing, from a limited number of colorimetric measurement points, the corrections to be applied to the control values of each colored dot so that the light emission of said dot corresponds to that of the reference display device. This application takes into account the measurement points closest to the colored dot. The tolerance on the corrections is sufficiently small that the colorimetric differences between the actual light emission of the display device and the reference emission are not perceptible to a human observer.