Digital Image Sensor Defective Pixel Detection and Correction
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Solution Overview
Problem
Electronic image sensors often include defective pixels that respond inappropriately to light, producing inaccurate sensor values, which is a challenge that existing technologies have not effectively addressed.
Innovation Solution
A digital image sensor system comprising an array of pixels and a processor that generates estimate values using sensor values from neighboring pixels to detect and correct defective pixels by calculating intensity ratios and determining threshold values to replace inaccurate readings with mean estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If defective pixels are present in the sensor array, then the sensor can capture images, but the image quality deteriorates due to inaccurate sensor values from defective pixels
Solution Approach 1:
The patent creates a corrected image by copying pixel values from neighboring pixels to replace defective pixel values. The processor generates corrected sensor values by copying from adjacent pixels in the same row or column, effectively replicating the function of healthy pixels to compensate for defective ones, thus maintaining image quality despite the presence of defective pixels
Solution Approach 2:
The patent introduces a corrected image as an intermediary product between the raw sensor data and the final image output. The processor compares raw sensor values with corrected sensor values (derived from neighboring pixels) and uses this intermediary corrected image to replace defective pixel readings, thereby mediating the impact of defective pixels on the final image quality
2Measurement precision
If the sensor array is large, then the image resolution improves, but the probability of containing defective pixels increases
Solution Approach 1:
The patent segments the sensor array into functional units (pixels) and applies localized correction procedures to each defective pixel independently. By processing each pixel's correctness individually using its neighboring pixels, the system can maintain high resolution across large arrays while managing the increased probability of defective pixels through targeted correction rather than requiring the entire array to be perfect
Solution Approach 2:
The patent enables the sensor array to correct its own defects using the functional pixels within the same array. Neighboring healthy pixels provide the data needed to correct defective pixels, allowing the array to self-diagnose and self-correct without requiring external intervention or a separate reference sensor, thus maintaining resolution while compensating for defective pixels
3Reliability
If pixel defects are detected and corrected using neighboring pixels, then image quality improves, but the processing complexity increases
Solution Approach 1:
The patent performs preliminary identification of defective pixels and pre-computation of corrected values using neighboring pixels before the final image output is generated. The processor identifies defective pixels and generates corrected sensor values in advance, allowing the complex correction process to be prepared beforehand and reducing the computational burden during actual image processing
Solution Approach 2:
The patent replaces complex hardware-based defect correction mechanisms with software-based processing algorithms. Instead of using additional physical sensors or hardware circuits to correct defects, the system uses computational algorithms that process sensor data through software, generating corrected images by copying from neighboring pixels, thereby reducing hardware complexity while maintaining image quality
Data Source
AI summary
A digital image sensor comprising an array of pixels and a processor is provided. The array of pixels comprises a current pixel in a first color plane that is configured to produce a current sensor value, a first plurality of pixels in the first color plane that is configured to produce a first plurality of sensor values, and a second plurality of pixels in the second color plane that is configured to produce a second plurality of sensor values. The processor is configured to generate a plurality of estimate values using the first plurality of sensor values and a plurality of intensity ratios associated with the second plurality of sensor values, and the processor is configured to determine whether the current pixel is defective using the plurality of estimate values and the current sensor value.