Visual Sub-band Decomposition for Adaptive Image Contrast

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Solution Overview

Problem

Conventional image processing methods fail to effectively address local variations in image contrast and edge detection, leading to suboptimal results in areas with varying illumination, as they often rely on global algorithms that do not adapt well to different regions of an image.

Innovation Solution

The method employs visual sub-band decomposition based on Human Visual System Characteristics (HVSC) to generate multiple sub-band images, which are then processed independently and fused back together, allowing for adaptive image enhancement and edge detection that accounts for local features and varying illumination levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If global algorithms are used for image processing, then processing simplicity is maintained, but local variations in contrast and edge detection performance deteriorate

Engineering Contradiction:
Improveprocessing simplicityVSAvoidlocal contrast detection accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The image is divided into multiple sub-bands based on human visual system characteristics, with different regions (luminance and chrominance) processed separately. This segmentation allows local adaptation while maintaining overall processing coherence, resolving the contradiction between global simplicity and local precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different processing strategies are applied to different sub-bands according to human visual sensitivity. Luminance sub-bands receive enhanced processing for edge detection, while chrominance sub-bands use simplified processing, optimizing local contrast detection without uniformly complicating the entire processing pipeline.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If sub-band decomposition based on HVSC is implemented, then local image processing accuracy is improved, but computational complexity increases

Engineering Contradiction:
Improvelocal image processing accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

By segmenting the image into sub-bands that align with human visual system characteristics, the decomposition enables targeted processing only where needed, reducing redundant computations while improving local accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Enhanced processing is applied selectively to luminance sub-bands where human visual sensitivity is highest, while chrominance sub-bands receive minimal processing. This partial action approach improves critical regions without uniformly increasing computational complexity across the entire image.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If conventional histogram equalization is used, then processing speed is maintained, but visual naturalness and edge detection quality deteriorate

Engineering Contradiction:
Improveprocessing speedVSAvoidedge detection quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The method segments the image into multiple sub-bands and processes them differently, allowing edge detection enhancement in luminance regions while maintaining processing efficiency through selective application of enhancement algorithms rather than global processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Edge detection and contrast enhancement are applied locally to luminance sub-bands where human visual sensitivity is highest, while chrominance sub-bands maintain their original characteristics. This local quality approach improves edge detection quality without requiring computationally intensive global processing.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS8285076B2Methods and apparatus for visual sub-band decomposition of signals
Publication Date: 2012.10.09 TRUSTEES OF TUFTS COLLEGE
  • US8285076B2 patent drawing
  • US8285076B2 patent drawing
  • US8285076B2 patent drawing

AI summary

Methods and apparatus for image processing include performing visual sub-band decomposition of an image using human visual system characteristics to generate a plurality of sub-band decomposed images, independently processing the plurality of sub-band decomposed images with at least one application, and fusing the independently processed sub-band decomposed images to reconstruct an output image.