Image Sensor Color Noise Reduction via Local 5x5 Window Interpolation
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Solution Overview
Problem
Conventional image sensor methods degrade image quality by controlling chroma through whole frame color distribution, leading to reduced image definition and quality due to color noise.
Innovation Solution
A method determining a dark condition in an image sensor by setting a 5×5 window around a center pixel, calculating RGB average values, and comparing them to threshold values to interpolate colors locally, preventing color noise without degrading chroma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chroma is controlled by using the color distribution of the whole frame, then color noise is reduced, but image definition and quality are degraded
Solution Approach 1:
The image processing is divided into local regions (e.g., skin regions, non-skin regions) rather than treating the whole frame uniformly. The processor determines chroma control parameters separately for each region type, allowing selective chroma reduction only where color noise is problematic while preserving chroma in regions where it is important for image quality.
Solution Approach 2:
Different chroma control strategies are applied to different regions of the image. Skin regions use one set of chroma control parameters while non-skin regions use another set. This local differentiation ensures that chroma is preserved where it matters (skin tones) and reduced where it causes noise (background areas), resolving the contradiction between noise reduction and quality maintenance.
2Object-affected harmful factors
If chroma is controlled by using the color distribution of the whole frame, then color noise is reduced, but image quality is lowered
Solution Approach 1:
The image is segmented into different region types (skin and non-skin) with separate chroma control processing for each. This segmentation allows the system to maintain high image quality in critical regions while still achieving noise reduction in less critical regions, thus improving overall reliability without sacrificing quality.
Solution Approach 2:
The invention applies local quality control by using different chroma control parameters for different image regions. Skin regions maintain their natural chroma for realistic appearance, while non-skin regions have chroma reduced to minimize noise. This localized approach ensures high image quality is maintained where it matters most.
Data Source
AI summary
Disclosed are a method for determining a dark condition in an image sensor to prevent a color noise and a method for interpolating colors. The present invention forms a window with a size of 5×5 array and determines a local color distribution based on a center pixel by using the window with the size of 5×5 array, thereby determining a dark condition with respect to the local color distribution. Thus, it is possible not to degrade chroma with respect to a whole image but locally degrade chroma, thereby producing a black and white image. Through differently and locally performing a color interpolation according to a dark condition determination, it is possible to correct an error of an imperfect black possibly generated during an expression of an imperfect black and white image due to the color interpolation and to reduce a color noise in the corresponding portion.