Image Processing Anti-Saturation Gain Adjustment
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Solution Overview
Problem
Conventional image processing devices experience saturation issues when a global gain value greater than 1 is applied, leading to loss of details in high brightness image frames due to the limited range of 8-bit data, resulting in a phenomenon where high grayscale values are displayed as maximum, causing detail loss.
Innovation Solution
An image processing method and device that utilize a default data-gain conversion relationship lookup table to adjust the gain processing, combining original and default conversion relationship curves to prevent saturation by dynamically selecting between them based on the original gain value, ensuring that high brightness details are maintained without exceeding the 8-bit data limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a global gain value greater than 1 is applied to enhance image brightness, then the brightness enhancement is improved, but saturation occurs causing loss of high brightness details
Solution Approach 1:
The patent segments the gain processing by creating separate processing paths for different grayscale ranges. A first processing circuit handles lower grayscale values with the original gain value, while a second processing circuit handles higher grayscale values with a adjusted gain value derived from a conversion relationship curve. This segmentation prevents saturation in the high brightness region while maintaining enhancement in lower brightness regions.
Solution Approach 2:
The patent applies different gain values to different regions of the image data based on their grayscale values. Instead of applying a uniform global gain, the system uses a conversion relationship curve to determine adjusted gain values for specific grayscale ranges, ensuring that high brightness regions receive appropriate gain adjustment to avoid saturation while other regions maintain the intended brightness enhancement.
2Illumination intensity
If a global gain value greater than 1 is applied to enhance image brightness, then the brightness enhancement is improved, but the image data exceeds the 8-bit data range causing saturation
Solution Approach 1:
The patent performs preliminary action by pre-establishing a conversion relationship curve that maps original grayscale values to adjusted grayscale values within the valid 8-bit range. This conversion relationship is determined before the actual image processing, allowing the system to predict and prevent saturation by ensuring that the adjusted gain values will keep the processed data within the 0-255 range.
Solution Approach 2:
The patent changes the gain parameter dynamically based on the grayscale value. Instead of using a fixed global gain value, the system derives adjusted gain values from a conversion relationship curve that adapts the gain parameter to each grayscale level, ensuring that the transformed data remains within the valid 8-bit range while still achieving brightness enhancement where needed.
3Device complexity
If a uniform gain processing is applied to all grayscale values, then the processing simplicity is improved, but the high brightness detail loss occurs
Solution Approach 1:
The patent divides the uniform gain processing into segmented processing circuits that handle different grayscale ranges separately. The first processing circuit applies the original gain value to lower grayscale values, while the second processing circuit applies adjusted gain values from the conversion relationship curve to higher grayscale values. This segmentation maintains reasonable processing complexity while preventing high brightness detail loss.
Data Source
AI summary
The image processing method includes: analyzing an image frame to obtain an original gain value corresponding to grayscale values of the image frame, wherein the original gain value is greater than 1; obtaining a lookup table recording conversion relationship between default grayscale values and default gain values, wherein the lookup table is used for performing anti-saturation processing on image data of the image frame; according to the original gain value, performing anti-saturation processing for the image frame by using the lookup table to obtain an adjusted conversion relationship of the image frame, wherein the adjusted conversion relationship defines a conversion relationship between different grayscale values of the image frame and corresponding adjusted gain values; and performing gain processing on image data of the image frame according to the adjusted conversion relationship.