Image Sensor Saturation Compensation Using Sub-Pixel Color Ratios
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Solution Overview
Problem
Existing image sensors suffer from distorted saturation pixel values, leading to degraded image quality, necessitating improved methods to compensate for these values using more accurate pixel values.
Innovation Solution
An image sensor that generates a color ratio of saturation pixel groups using sub-pixel values to compensate for full pixel values, employing a pixel array, readout circuit, and image signal processor to enhance image quality through high dynamic range processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full pixel values are used in image data, then image processing can be performed, but saturation pixel values become distorted and image quality deteriorates
Solution Approach 1:
The patent segments the pixel array into multiple pixel groups (e.g., 2x2 blocks), where each group contains multiple pixels that share a common color filter. By processing pixel groups rather than individual pixels, the system can identify saturation conditions more reliably and apply compensation techniques to maintain accuracy while preserving processing capability.
Solution Approach 2:
The patent introduces color ratio data as an intermediary element. This color ratio, derived from the relationships between different color components within a pixel group, serves as a mediator to detect saturation conditions and guide the compensation process, allowing the system to correct distorted values without losing processing efficiency.
2Measurement precision
If saturation pixel values are compensated using traditional methods, then image quality may improve, but processing complexity and time increase
Solution Approach 1:
The patent performs preliminary actions by pre-calculating color ratios for each pixel group and storing them in lookup tables. During actual image processing, these pre-computed color ratios are quickly retrieved and applied to compensate for saturation, avoiding the need for complex real-time calculations and significantly reducing processing time while maintaining accuracy.
Solution Approach 2:
The patent changes the parameter used for saturation detection from individual pixel intensity values to color ratio values derived from multiple pixels. This parameter transformation allows for more accurate saturation detection with simpler computation, as color ratios are less sensitive to noise and lighting variations compared to absolute intensity measurements.
3Measurement precision
If color ratio is generated using sub-pixel values, then compensation accuracy improves, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple pixels within each pixel group to generate color ratio data. By combining the signal information from multiple pixels that share color filters, the system achieves more accurate color information and saturation detection without requiring additional separate sensing elements, thus improving accuracy while keeping the physical device structure relatively simple.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution improves image quality by accurately compensating for saturation pixel values, enhancing the reliability and accuracy of high dynamic range processing.
Implementation Method 1
The image sensors generate image data of the objects by using photoelectric conversion elements which react according to intensity of light reflected or emitted from the objects
Data Source
AI summary
An image sensor is provided. The image sensor includes: pixel groups; a readout circuit configured to output full pixel values respectively corresponding to the pixel groups and sub pixel values respectively corresponding to the pixel groups, wherein a full pixel value is generated based on pixel signals of all pixels in a first pixel group, and a sub pixel value is generated based on some of the pixel signals in the first pixel group; and an image signal processor configured to: generate, based on the full pixel value indicating the first pixel group is a saturation pixel group, a color ratio of the saturation pixel group by using a target sub pixel value corresponding to the saturation pixel group; and compensate for the full pixel value of the saturation pixel group based on the color ratio of the saturation pixel group.