Image Luminance Decomposition for Contrast Enhancement

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Solution Overview

Problem

Display devices often struggle to accurately represent images, leading to overexposure in bright areas and underexposure in dark areas, making it difficult to distinguish details and maintain contrast.

Innovation Solution

A system processes an original image by decomposing its luminance, adjusting pixel frequencies, and reconstructing the image to enhance contrast, using techniques like wavelet transformation and frequency adjustment to generate a final image with improved luminance and detail preservation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If display devices display images with high luminance range, then brightness coverage is improved, but contrast and detail visibility deteriorate in bright and dark areas

Engineering Contradiction:
Improveluminance rangeVSAvoiddetail visibility
Core Design Contradiction:
Illumination intensityVSLoss of information

Solution Approach 1:

The luminance image is decomposed into multiple frequency sub-bands using wavelet transformation, separating the image into approximation coefficients (low frequency) and detail coefficients (high frequency). This segmentation allows independent processing of different frequency components to preserve details while managing luminance range.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Frequency adjustment is applied selectively to different sub-bands based on their characteristics. The detail coefficients (high frequency) receive different treatment compared to approximation coefficients (low frequency), with gain adjustment tailored to each sub-band to preserve local detail quality while managing overall luminance.

Inventive Principle:
Principle #3Local quality

2Loss of information

If image processing enhances contrast, then detail visibility is improved, but image processing complexity increases

Engineering Contradiction:
Improvedetail visibilityVSAvoidprocessing complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The processing extracts only the luminance component from the original image, separating it from chrominance information. This extraction reduces processing complexity by focusing computational resources on the luminance channel where contrast enhancement is most critical for detail visibility.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Wavelet decomposition is performed as a preliminary step before frequency adjustment, organizing the luminance image into structured sub-bands. This preliminary organization simplifies subsequent processing by providing a framework for targeted frequency manipulation without requiring complex real-time analysis.

Inventive Principle:
Principle #10Preliminary action

3Loss of information

If frequency adjustment is applied to all pixels, then contrast enhancement is improved, but processing time and computational load increase

Engineering Contradiction:
Improvecontrast enhancementVSAvoidprocessing time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

Frequency adjustment is applied selectively to specific sub-bands and regions rather than uniformly to all pixels. The detail coefficients (high frequency sub-bands) receive frequency adjustment while approximation coefficients receive different treatment, reducing overall computational load while maintaining contrast enhancement where most beneficial for detail visibility.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS11094045B2Systems and methods for image processing
Publication Date: 2021.08.17 ZHEJIANG DAHUA TECH CO LTD
  • US11094045B2 patent drawing
  • US11094045B2 patent drawing
  • US11094045B2 patent drawing

AI summary

According to aspects of the present disclosure, methods, systems, and media for processing an image are provided. A system may include at least one computer-readable storage medium including a set of instructions for processing an original image, and at least one processor in communication with the at least one computer-readable storage medium. When executing the set of instructions, the system is directed to obtain a first luminance image of the original image; decompose the first luminance image to provide a plurality of first decomposed images; adjust pixel frequencies in at least some of the plurality of first decomposed images to generate a plurality of second decomposed images; generate a second luminance image of the original image based on the plurality of second decomposed images; and determine a final image of the original image based on the first luminance image, the second luminance image, and the original image.