Color Vision Variability Test System Using Metameric Patterns
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Solution Overview
Problem
Current color vision deficiency tests are inadequate in assessing color vision variability among individuals, particularly with the advent of narrowband fluorescent lamps and LEDs, as they rely on a single standard observer that fails to account for individual differences in color matching functions due to factors like age, gender, and viewing conditions.
Innovation Solution
A test system comprising two-dimensional patterns with metameric colors and a processing unit that predicts color matching functions and identifies congenital or acquired color vision deficiencies by calculating variations in selected spots compared to a reference spot, considering the specific spectral power distribution of the illuminant, and using a generic algorithm to derive individual causes of color vision variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single standard observer is used for color vision testing, then the test system is simple and easy to operate, but it fails to account for individual differences in color matching functions
Solution Approach 1:
The patent segments the single standard observer into multiple individual observer models, each with their own color matching functions. The test system divides the population into different observer types (e.g., young adults, elderly, males, females) and assigns appropriate CMFs to each, allowing personalized color vision assessment while maintaining systematic organization.
Solution Approach 2:
The patent changes the parameters of the observer model by selecting different color matching functions based on observer characteristics such as age, gender, and lighting conditions. The system dynamically adjusts the CMF parameters to match the specific test subject, improving measurement accuracy without requiring a completely new test system.
2Device complexity
If traditional color vision tests are used, then the testing process is simple, but they cannot detect acquired color vision deficiencies caused by factors like lens yellowing or macular pigment
Solution Approach 1:
The patent introduces pre-retinal filters as intermediary elements that simulate the effects of lens yellowing and macular pigment between the light source and the retina. These filters allow the test system to model acquired color vision deficiencies without changing the physical test apparatus, enabling detection of both congenital and acquired conditions.
Solution Approach 2:
The patent makes the test system dynamic by allowing adjustment of observer characteristics and lighting conditions during testing. The system can adapt to different test scenarios (e.g., testing elderly observers with yellowed lenses, or testing under different illuminants) by dynamically changing the underlying CMF models and filter parameters.
3Adaptability or versatility
If standard illuminants are not used in color matching tests, then the test reflects real-world viewing conditions better, but the results become highly variable and unreliable
Solution Approach 1:
The patent performs preliminary calculations to determine the appropriate color matching functions and pre-retinal filter combinations before conducting the actual color vision test. By pre-computing the expected color matches for different observer types and lighting conditions, the system establishes reliable reference points that account for real-world variability while maintaining measurement consistency.
Data Source
AI summary
The present invention relates to a test system for assessing color vision variability of test persons (7). The test system comprises at least two test carriers (1), wherein each of the at least two test carriers (1) is provided with a two-dimensional pattern (4) including a background (2) and a plurality of samples (3). The plurality of samples (3) and the background (2) of each one of the at least two test carriers (1) are made of at least two different dyestuff combinations representing metameric colors. The samples (3) and/or the background (2) show color scaling in at least two directions such that each one of the at least two test carriers (1) is configured to provide that a test person (7) can select a spot (PISC) from the two-dimensional pattern (4) where the metameric colors of the samples (3) and the background (2) match best. The system further comprises a test illuminant unit (5) configured to provide light for the color vision variability assessment, the light having a specific spectral power distribution. The system further comprises a processing unit (6) configured to predict a color matching function and/or to determine a congenital and/or acquired color vision deficiency of the test person (7) by calculating a variation of the spot (PISC) selected by the test person (7) as compared to a spot (PISS) computed by the processing unit (6) based on data of a predefined standard observer considering the specific spectral power distribution of the light of the test illuminant unit (5).