Solid-State Imaging Device Defect Correction for High Dynamic Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current image sensors using the SVE method lack efficient defect correction processing for high dynamic range imaging, particularly in handling defective pixels across varying exposure times and sensitivities.
Innovation Solution
A solid-state imaging device with a pixel array and a pixel value correcting unit that adjusts pixel values based on exposure time and sensitivity, utilizing a saturation determining unit, flatness determining unit, direction detecting unit, defect determining unit, and defect correcting unit to identify and correct defective pixels by interpolating or mixing pixel values from neighboring pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If defect correction processing is performed using conventional methods on SVE image sensors, then defective pixels can be corrected, but the correction accuracy deteriorates due to varying exposure times and sensitivities across different pixel regions
Solution Approach 1:
The patent applies local quality by creating multiple defect correction maps (first defect correction map and second defect correction map) corresponding to different exposure time groups. Each map is generated using pixel data from pixels with matching exposure characteristics, ensuring that defect correction is performed using data from pixels under similar exposure conditions, thereby maintaining high correction accuracy across varying exposure conditions.
Solution Approach 2:
The patent segments the pixel array into multiple groups based on exposure time characteristics. Pixels are divided into first pixels (short exposure time) and second pixels (long exposure time), with separate defect correction processing applied to each group. This segmentation allows the system to handle the complexity of varying exposure conditions by treating each group independently with appropriate correction parameters.
2Measurement precision
If multiple defect correction maps are generated for different exposure time groups, then defect correction accuracy improves, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by generating defect correction maps in advance during the imaging process, before final image output. The first defect correction map is generated using pixel data from first pixels, and the second defect correction map is generated using pixel data from second pixels. These pre-computed maps are then applied to correct defective pixels in the final image, separating the complex computation from the final output stage.
Solution Approach 2:
The patent changes processing parameters based on exposure time groups. Different defect correction algorithms and parameter sets are applied to different pixel groups: pixels with short exposure time use one set of correction parameters, while pixels with long exposure time use another set. This parameter adaptation allows accurate defect correction without requiring a single complex algorithm to handle all cases.
3Productivity
If defect correction is performed without considering exposure time variations, then processing speed is maintained, but correction reliability deteriorates
Solution Approach 1:
The patent applies dynamics by making the defect correction process adaptive to exposure time conditions. The system dynamically selects which defect correction map to apply based on the exposure time of each pixel: pixels with short exposure time use the first defect correction map, while pixels with long exposure time use the second defect correction map. This dynamic adaptation ensures reliable defect correction across varying exposure conditions while maintaining processing efficiency through pre-computed maps.
Data Source
AI summary
A solid-state imaging device includes a pixel array and a pixel value correcting unit. The pixel array includes a plurality of pixels, the plurality of pixels each having one of a different exposure time and a different exposure sensitivity and being disposed according to a predetermined rule. The pixel value correcting unit is configured to correct, among pixel values obtained from the plurality of pixels in the pixel array, a pixel value of a pixel of the plurality of pixels that applies to a preset condition, by using a pixel value of another pixel of the plurality of pixels.