Image Sensor Gain Matrix for Crosstalk Reduction
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Solution Overview
Problem
Advanced image sensors with complex colour filter arrays, such as RGBW, experience significant pixel crosstalk issues, resulting in an artificial periodic grid-like structure on white pixels due to interactions between white and colour pixels, which current methods fail to adequately address.
Innovation Solution
A grid-based gain system is applied to the image data, where each pixel is multiplied by specific gain factors from a gain matrix, which is virtually positioned over the pixel array, allowing for varying gain values to reduce crosstalk effects, particularly for white pixels, and is calibrated using a flat-field reference image to match the colour filter array pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex colour filter array pattern (e.g., RGBW) is used to enhance colour information, then colour accuracy is improved, but pixel crosstalk increases causing artificial grid-like structures on white pixels
Solution Approach 1:
The patent applies different gain factors to different regions of the image based on their position in the colour filter array pattern. Specifically, white pixels are multiplied by a first gain factor while colour pixels are multiplied by a second gain factor, creating local variations in processing intensity to compensate for crosstalk effects in specific locations
Solution Approach 2:
The patent changes the gain parameter dynamically based on pixel type and position. By introducing position-dependent gain factors (first gain for white pixels, second gain for colour pixels) and applying them through a gain matrix that varies across the image, the system adjusts processing parameters to mitigate crosstalk while preserving colour accuracy
2Object-generated harmful factors
If a gain matrix is applied to reduce crosstalk effects, then pixel crosstalk is reduced, but computational complexity increases
Solution Approach 1:
The gain matrix is divided into distinct regions corresponding to different pixel types in the colour filter array pattern. The matrix is constructed with specific gain values for white pixel positions and different gain values for colour pixel positions, allowing systematic computation that reduces crosstalk while managing complexity through structured organization
Solution Approach 2:
The gain matrix is pre-calculated and stored before image processing. By preparing the gain matrix in advance with appropriate gain values for different positions and pixel types, the actual image processing only requires matrix multiplication, significantly reducing real-time computational complexity
Data Source
AI summary
The invention discloses a method for processing of image data provided by an image sensor, wherein the image data comprises a frame formed by an array of pixels, said pixel array being overlaid with a colour filter array so that the pixels represent colour information according to a specific colour pattern defined by the colour filter array. The method includes the step of multiplying each pixel of the frame by a respective gain factor pre-defined in a stored gain matrix for a pixel position which corresponds to the pixel in the frame when the gain matrix is positioned on the frame, wherein the gain matrix is smaller than the frame and is placed in a plurality of different positions on the frame to multiply each pixel of the frame by a respective gain factor of the gain matrix.