Image Contrast Enhancement via Power and Logarithm Transforms
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Solution Overview
Problem
Low-contrast environments significantly impede human and machine visibility, particularly in nighttime driving and other applications, where existing technologies fail to effectively enhance image contrast and visibility simultaneously, especially for reflective surfaces like street signs.
Innovation Solution
A system that employs a combination of power and logarithm transform methods, along with image fusion techniques, to enhance image contrast and visibility, using multiple sensors and illumination assistance devices like infrared illuminators, and applies mathematical operations on pixel values to create enhanced images in real-time or batch processing modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If standard image enhancement methods are used, then visibility in dark areas is improved, but text on reflective surfaces like street signs becomes over-enhanced and loses readability
Solution Approach 1:
The patent applies different enhancement strengths to different regions of the image. Dark areas receive stronger enhancement to improve visibility, while reflective surfaces like street signs receive controlled enhancement to maintain text readability. This is achieved through region-specific processing that adapts the enhancement parameter locally rather than applying a uniform enhancement across the entire image.
2Loss of information
If enhancement strength is increased to improve dark area visibility, then overall image contrast is improved, but text on street signs becomes over-enhanced
Solution Approach 1:
The patent dynamically adjusts enhancement parameters based on local image characteristics. By analyzing the properties of different regions (dark areas versus reflective surfaces), the system modifies enhancement parameters to achieve optimal contrast improvement without over-enhancing text on street signs, thus preserving information while improving overall image quality.
3Device complexity
If uniform enhancement is applied across the entire image, then processing simplicity is maintained, but different regions receive inappropriate enhancement levels
Solution Approach 1:
The system implements region-specific enhancement processing where different parts of the image receive tailored enhancement levels. Dark areas, road surfaces, and reflective surfaces like street signs are identified and processed with appropriate enhancement parameters, ensuring each region receives the correct level of enhancement while maintaining manageable processing complexity through efficient region classification.
Data Source
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AI summary
A system (20) and method for enhancing the contrast within an image. An enhanced image (24) can be generated in a real-time or substantially real-time manner from an initial image (22). A low-contrast image is enhanced, including the visibility of text within the low-contrast image. A logarithm transform method (38) is used to enhance the overall contrast and visibility within the image. A power transform method (36) is used to enhance the visibility and contrast of written text, symbols and other forms of signs within the enhanced image (24).