Imaging Colorimeter System for Display Chromaticity Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current imaging colorimeter systems for display testing are complex, expensive, and inefficient in providing spatially resolved chromaticity and luminance measurements, especially when dealing with matrix displays, as they require large and costly equipment for accurate spectral separation.
Innovation Solution
An RGB camera is used for spatially resolved measurement of chromaticity, transforming RGB color values into tristimulus values using a 3x3 transformation matrix, with corrections derived from a second portion of light measured by a photoelectric or spectral photometer to achieve accurate and cost-effective two-dimensional mapping of tristimulus values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spectral photometers are used for accurate chromaticity and luminance measurement, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention divides the measurement task into two parts: a spectral photometer measures accurate reference values at a single point, while an imaging colorimeter performs spatially resolved measurements across the entire display. The spectral photometer's high precision is used only where needed for calibration, while the imaging colorimeter handles the bulk of spatial measurements, thus achieving overall high accuracy without requiring the entire system to be as complex as a full spectral photometer array.
Solution Approach 2:
The invention introduces an intermediary correction process where the spectral photometer's single-point measurements are used to generate correction factors that are then applied to the imaging colorimeter's spatial measurements. This intermediary step allows the simpler imaging colorimeter to achieve spectral photometer-level accuracy through post-processing correction, avoiding the need for complex spectral separation in every measurement channel.
2Measurement precision
If spectral photometers are used for accurate chromaticity and luminance measurement, then measurement precision is improved, but equipment cost increases
Solution Approach 1:
The system segments the measurement functions between a single spectral photometer and multiple imaging colorimeter channels. Only one spectral photometer is required for reference measurements, while the imaging colorimeter handles all spatially resolved measurements. This segmentation dramatically reduces the number of expensive spectral separation components needed, lowering overall system cost while maintaining measurement precision through the correction process.
Solution Approach 2:
The invention creates a virtual copy of the spectral photometer's measurement capability by using the imaging colorimeter to capture spatial information and then applying correction factors derived from the spectral photometer. This allows the system to achieve spectral photometer-level accuracy across the entire display without physically deploying multiple spectral photometers, thus reducing equipment cost.
3Productivity
If imaging colorimeters are used for spatially resolved measurement, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The system implements a feedback mechanism where the spectral photometer periodically measures reference values at a single point, and these measurements are used to generate correction factors that are applied to the imaging colorimeter's spatial measurements. This feedback loop ensures that the high-speed imaging colorimeter maintains spectral photometer-level accuracy by continuously correcting for any drift or inaccuracies, thus resolving the precision-speed tradeoff.
Solution Approach 2:
The spectral photometer performs preliminary measurements at a single point to establish accurate reference tristimulus values before the imaging colorimeter performs spatially resolved measurements. These preliminary reference measurements are used to create correction factors that pre-compensate for any inaccuracies in the imaging colorimeter's spectral response, allowing the system to achieve high speed without sacrificing precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables fast, cost-effective, and high-accuracy assessment of display defects and quality, including uniformity and color accuracy, with the ability to detect dynamic photometric parameters, while minimizing measurement errors and equipment size and cost.
Implementation Method 1
a beam splitter which divides light incident from the sample into a first portion of light and a second portion of light
Implementation Method 2
The first portion of light is received by an RGB camera such that a two-dimensional map of RGB color values is produced
Implementation Method 3
The second portion of light is received by a colorimeter which produces tristimulus values
Data Source
AI summary
The invention relates to a method for two-dimensional, spatially resolved measurement of tristimulus values of light emitted from a plurality of positions on a sample. It is an object of the invention to provide an improved method and system for spatially resolved chromaticity and luminance measurement in a standardized color space for display testing. The method of the invention comprises the steps of: - directing a first portion of the light to an RGB camera which produces a two-dimensional map of RGB color values; - transforming the RGB color values into first tristimulus values to produce a map of tristimulus values; - directing a second portion of the light to a colorimeter which produces second tristimulus values; - deriving a tristimulus correction by comparing the second tristimulus values with at least a subset of the first tristimulus values; and - applying the tristimulus correction to the first tristimulus values to produce a corrected map of tristimulus values. Moreover, the invention relates to an imaging colorimeter system capable of two-dimensional, spatially resolved measurement of tristimulus values of light emitted from a plurality of positions on a sample.