Image Corrector Luminance Ratio Adjustment for Low Illumination
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Solution Overview
Problem
Image processing apparatuses installed in mobile objects, such as vehicles, face challenges in accurately determining RGB luminance-value ratios under low illumination conditions due to non-uniform light entry into photodiodes, leading to reduced accuracy in color recognition.
Innovation Solution
An image processing apparatus that measures illumination levels and uses predetermined ascertainment data to correct luminance-value ratios for each pixel, independently of color filter sensitivity differences, ensuring accurate color representation under varying brightness conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional image processing is used under low illumination conditions, then the imaging unit can capture images, but the accuracy of RGB luminance-value ratios deteriorates due to non-uniform light entry into photodiodes
Solution Approach 1:
The patent applies parameter changes by adjusting the correction values based on illumination level conditions. Different correction values are selected from predetermined sets depending on whether the illumination level is high or low, thereby optimizing the luminance-value ratio calculation for specific lighting conditions and resolving the inaccuracy caused by non-uniform light entry under low illumination.
Solution Approach 2:
The patent implements feedback by using ascertainment data that is determined based on the actual illumination level measured during image capture. The correction process uses feedback information about the illumination conditions to adjust the luminance-value ratios, ensuring accurate color representation despite variations in light entry into photodiodes.
2Measurement precision
If color filter sensitivity differences are not compensated, then the imaging process remains simple, but color recognition accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-determining and storing multiple sets of correction values corresponding to different illumination levels before actual image capture. During image processing, the system simply retrieves the appropriate pre-computed correction values based on the measured illumination level, thereby achieving accurate color recognition without complex real-time calculations.
Solution Approach 2:
The patent uses parameter changes by switching between different correction value sets based on illumination level. This allows the system to compensate for color filter sensitivity differences adaptively, improving color recognition accuracy while maintaining computational efficiency through predefined correction parameters.
3Measurement precision
If illumination level is not considered in correction, then the processing flow is simpler, but the accuracy of color representation under varying brightness conditions deteriorates
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing correction values for multiple illumination levels during system setup. During actual operation, the system only needs to measure the current illumination level and retrieve the corresponding pre-computed correction values, thereby achieving accurate color representation without adding significant complexity to the real-time processing flow.
Solution Approach 2:
The patent applies feedback by incorporating illumination level measurement into the image processing workflow. The measured illumination level serves as feedback information that guides the selection of appropriate correction values, ensuring accurate color representation while maintaining a relatively simple processing structure through condition-based selection.
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
Improves the accuracy of RGB luminance-value ratios for each pixel, enhancing color recognition and reducing errors in image processing, especially in low-light conditions.
Implementation Method 1
The imaging unit is comprised of a plurality of photodiodes and a color filter array
Data Source
AI summary
In an image processing apparatus, an image corrector ascertains, for each pixel of a selected pixel region included in an image captured by an imaging unit, luminance-value ratios of respective colors of color filters in accordance with (i) a color luminance value of the corresponding pixel of the selected pixel region, and (ii) ascertainment data items predetermined for the respective colors if a measured illumination level around the imaging unit is lower than or equal to a predetermined threshold illumination level. The ascertainment data item, predetermined for each color, represents a corresponding color luminance-value ratio at any pixel in the selected pixel region with respect to a predetermined peak luminance value of the corresponding color in the selected pixel region. The image corrector generates a corrected image in accordance with the luminance-value ratios of the respective colors ascertained for each pixel of the selected pixel region.