Image Noise Reduction via Variance-Based Pixel Classification

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Solution Overview

Problem

Conventional image processing methods that reduce spatial noise often blur detailed image portions and reduce sharpness, as they fail to effectively distinguish and preserve characteristic pixels.

Innovation Solution

A method and apparatus that utilize statistical analysis to identify characteristic pixels by calculating variances within operating blocks, filtering non-characteristic pixels to reduce noise while maintaining detailed image portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a filter is used to process the received image to remove spatial noise, then the spatial noise is reduced, but the detailed portions of the image are removed and image sharpness is reduced

Engineering Contradiction:
Improvespatial noiseVSAvoidimage sharpness
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies different processing treatments to different regions of the image based on local characteristics. By calculating variance values for different pixel regions, the system identifies characteristic pixels (edges, textures) and applies filtering only to non-characteristic pixels, thereby achieving local adaptive noise reduction that preserves important image details and sharpness while removing spatial noise.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If conventional filtering methods are applied to reduce spatial noise, then noise removal is achieved, but edge information is lost and image detail is blurred

Engineering Contradiction:
Improvespatial noiseVSAvoidedge information
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent uses variance values (a statistical property analogous to 'color' in this context) to identify and differentiate characteristic pixels from non-characteristic pixels. By analyzing the variance of pixel values in local regions, the system can detect edges and detailed portions (which have high variance) versus smooth regions (which have low variance), thereby selectively applying noise reduction only where appropriate and preserving edge information.

Inventive Principle:
Principle #32Color changes

Data Source

PatentUS9031353B2Method and apparatus for reducing spatial noise of images
Publication Date: 2015.05.12 NOVATEK MICROELECTRONICS CORP
  • US9031353B2 patent drawing
  • US9031353B2 patent drawing
  • US9031353B2 patent drawing

AI summary

A method for reducing spatial noise of images includes the following steps. A target pixel is obtained and an operating block is built accordingly. Pixel values of the target pixel and multiple neighboring pixels in the operating block are operated to obtain a variance corresponding to the operating block. Whether the target pixel is characteristic is judged according to the variance. If the target pixel is not characteristic, the multiple pixels in the operating block are filtered to obtain a modulated pixel value. The pixel value of the target pixel is updated to the modulated pixel value.