Dead Pixel Correction Using OTP Memory Storage
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Solution Overview
Problem
Conventional dead pixel correction methods in image sensors face challenges in accurately detecting and correcting dead pixels, especially when they are adjacent, due to limitations in hardware resources and the use of probabilistic compensation methods, leading to reduced compensation ratios.
Innovation Solution
A dead pixel correction apparatus and method that includes a storage unit for storing dead pixel position information, a data scanning section, a valid data determination section, a pre-processing section, and a correction section, which corrects pixel values using pre-processed data stored in an OTP memory, allowing for efficient correction of both single and adjacent dead pixels with minimal control logic and without the need for static random access memory (SRAM).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a probabilistic compensation method is used for dead pixel correction, then the correction can be performed with simple hardware, but the compensation ratio is reduced and accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-storing the position information of dead pixels in an OTP memory before normal image capture operations. During normal operation, the system simply retrieves this pre-stored position information rather than performing complex real-time analysis, thereby achieving accurate dead pixel correction without requiring complex hardware resources during actual imaging.
Solution Approach 2:
The patent replaces the conventional mechanical/probabilistic approach of real-time dead pixel detection with a data storage and retrieval system. Instead of using complex hardware to analyze and detect dead pixels during operation, the system substitutes this with an OTP memory that stores position information, replacing the need for complex real-time processing hardware.
2Quantity of substance
If a kernel with limited size is used for dead pixel correction, then hardware resources are conserved, but the compensation ratio is reduced especially when dead pixels are adjacent
Solution Approach 1:
The patent extracts only the essential position information of dead pixels and stores it in the OTP memory, separating this critical data from the complex real-time processing requirements. By extracting and pre-storing just the position coordinates, the system eliminates the need for complex kernel-based analysis hardware while maintaining the ability to correct both single and adjacent dead pixels effectively.
3Device complexity
If conventional dead pixel correction methods are used, then simple hardware schemes can be implemented, but the yield of image sensors is reduced due to inaccurate correction
Solution Approach 1:
The patent implements preliminary action by performing dead pixel position identification and storage in OTP memory before the image sensor enters normal production use. This pre-characterization approach ensures that all dead pixels are accurately identified and recorded, enabling reliable correction during normal operation and thereby improving overall sensor yield without requiring complex correction hardware.
Data Source
AI summary
A dead pixel correction apparatus includes a storage unit suitable for storing position information of dead pixels obtained from pixel data, a data scanning section suitable for scanning the position information stored in the storage unit, a valid data determination section suitable for determining valid data with respect to the scanned position information, a valid data pre-processing section suitable for pre-processing the determined valid data, and a dead pixel correction section suitable for correcting pixel values corresponding to the dead pixels in current pixel data based on the pre-processed valid data, and outputting the corrected pixel data.