Bayer Sensor Image Processing with Adaptive Interpolation

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Solution Overview

Problem

Current image processing methods for Bayer sensors fail to simultaneously reduce blurring, zipper artifacts, color fringes, and maze artifacts, especially at sharp edges and diagonal structures, while also being cost and power efficient with limited memory.

Innovation Solution

An image processing method that involves generating a color image by interpolating missing color values from raw image data, using a sharpening term to enhance the image, and applying thresholding and median calculations to reduce noise and artifacts, while determining orientation for adjusted interpolation, all performed in parallel and independently to avoid amplifying noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If color interpolation is performed using nearby pixels, then missing color values are filled in, but blurring of sharp edges and zipper artifacts occur

Engineering Contradiction:
Improvemissing color valuesVSAvoidedge sharpness
Core Design Contradiction:
Loss of informationVSManufacturing precision

Solution Approach 1:

The patent applies different interpolation strategies for different regions of the image. It detects edges and applies stronger interpolation smoothing in regions with smooth color transitions while using weaker interpolation or no interpolation in regions with sharp edges. This local adaptation of interpolation strength resolves the contradiction by preserving edge sharpness where needed while filling missing color values where appropriate.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts the interpolation process based on detected image characteristics. It performs multiple passes of interpolation with varying strengths and adapts the interpolation parameters based on the presence of edges, patterns, or noise in different regions. This dynamic adjustment allows the system to optimize between filling missing values and preserving edge sharpness on a per-region basis.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If interpolation is adjusted based on image structure detection, then blurring is reduced, but maze artifacts and poor reproduction of diagonal structures occur

Engineering Contradiction:
Improveedge sharpnessVSAvoiddiagonal structure reproduction
Core Design Contradiction:
Manufacturing precisionVSLoss of information

Solution Approach 1:

The patent changes the interpolation parameters based on the detected orientation and structure of image regions. When diagonal structures are detected, the system adjusts interpolation parameters to better handle diagonal edges, using techniques such as rotating the interpolation grid or applying anisotropic filtering. This parameter adaptation allows the system to reduce blurring while improving diagonal structure reproduction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the image into different regions based on detected structures (edges, patterns, noise) and applies different interpolation methods to each segment. By dividing the image into homogeneous regions and treating them differently, the system can optimize for edge sharpness in some regions while maintaining diagonal structure reproduction in others, avoiding the artifacts that occur with uniform interpolation approaches.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If multiple interpolation methods are applied to reduce artifacts, then image quality improves, but processing complexity and computational cost increase

Engineering Contradiction:
Improveartifact reductionVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary image analysis to detect edges, patterns, and noise before applying interpolation. This preliminary detection guides the subsequent interpolation process, allowing the system to apply appropriate methods only where needed rather than using complex multi-method approaches everywhere. The preliminary action simplifies the overall process by pre-determining the interpolation strategy for each region.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The interpolation system uses the image data itself to determine the appropriate interpolation strategy. By analyzing the local characteristics of the image (edges, patterns, noise levels), the system automatically selects and adjusts interpolation parameters without requiring external control or complex processing pipelines. This self-service approach reduces processing complexity while maintaining high artifact reduction effectiveness.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS7751642B1Methods and devices for image processing, image capturing and image downscaling
Publication Date: 2010.07.06 ARM LTD
  • US7751642B1 patent drawing
  • US7751642B1 patent drawing
  • US7751642B1 patent drawing

AI summary

An image processing method comprises receiving a raw color image as produced by an image sensor. A color image having a plurality of pixels is generated by processing raw image data from said raw color image, wherein pixels for which color values are absent in said raw image data are assigned color values derived from present color values in said raw image data. A sharpening term is generated by processing raw image data from said raw color image. Then, an improved color image is produced by combining said color image with said sharpening term. The raw color image may be a Bayer image, and the image processing method may be implemented in a cost and power efficient integrated circuit using limited memory.