Mosaic Image Max Min Filter for Hot Pixel Correction
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Solution Overview
Problem
Existing image processing methods for defective pixels in color image sensors can erase isolated bright spots and introduce color artifacts, leading to breakdown of image structure, especially in night scenes with densely distributed bright spots.
Innovation Solution
An image processing device that corrects pixel values by calculating maximum or minimum values among neighboring pixels, including both same-color and different-color pixels, to replace defective pixel values while minimizing structural breakdown, using a Max/Min filter that references pixels within specific ranges to accurately estimate and correct hot and cold pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Max/Min filter references only same-color neighboring pixels in a large range (e.g., 5×5 pixel range), then defective pixels can be corrected, but isolated bright spots may be erased and color artifacts may occur
Solution Approach 1:
The patent segments the correction process by applying different reference strategies for different pixel types: for same-color pixels, it references same-color neighboring pixels; for different-color pixels, it references different-color neighboring pixels. This segmentation prevents color artifacts while maintaining correction effectiveness.
Solution Approach 2:
The patent applies local quality by adapting the reference pixel selection to the specific color component of each pixel being corrected. Each pixel uses reference pixels of the same color, ensuring that correction is performed within the appropriate color channel and preventing color contamination.
2Reliability
If a Max/Min filter adjusts brightness levels of densely distributed bright spots, then defective pixels are corrected, but the bright spots are resolved as an anomalous linear structure
Solution Approach 1:
The patent ensures that each pixel is corrected using only reference pixels of the same color, maintaining local color consistency. This prevents the formation of anomalous linear structures by avoiding cross-color contamination that would distort the spatial arrangement of bright spots.
Solution Approach 2:
Instead of forcing all pixels to conform to a uniform brightness model, the patent inverts the approach by allowing each pixel to be corrected based on its own color channel characteristics, preserving the natural variation in brightness levels of different bright spots.
Data Source
AI summary
An image processing device that corrects a pixel value in image data, includes: an input unit that inputs image data having a plurality of color components and including a plurality of pixels each holding one color component; a calculation unit that calculates a maximum value among pixel values of a plurality of same-color neighboring pixels each holding a color component identical to a color component held in a processing target pixel selected from the pixels included in the image data and pixel values of a plurality of different-color neighboring pixels each holding a color component different from the color component held in the processing target pixel, which take up positions closer to the processing target pixel than the plurality of same-color neighboring pixels; and a correction unit that compares a pixel value of the processing target pixel with the maximum value and replaces the pixel value of the processing target pixel with the maximum value if the pixel value of the processing target pixel is greater than the maximum value.