Image Sensor Vertical Transfer Defect Detection and Correction
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Solution Overview
Problem
Conventional methods are insufficient in precisely correcting linear display failures in image pickup sensors due to the influence of dark current from the vertical transfer section, leading to deteriorated image quality.
Innovation Solution
An image processing method that halts charge transfer for a predetermined time, identifies defect positions, and corrects defective signal levels by subtracting signal levels from optical black regions to address the linear display failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional correction methods are used, then correction process is simple, but correction precision is insufficient due to dark current influence
Solution Approach 1:
The patent applies preliminary action by performing a dark current correction process before the main image capture. The transfer section transfers charges for a predetermined period without light input to generate a dark current correction image, which is then used to correct the actual captured image. This preliminary correction eliminates the influence of dark current on subsequent imaging, thereby improving correction precision without significantly increasing overall system complexity.
2Reliability
If image quality is improved by correcting vertical transfer defects, then display failure correction is achieved, but processing time increases due to additional correction steps
Solution Approach 1:
The patent merges the dark current correction process with the normal image capture process. The transfer section performs both regular charge transfer for image capture and dark current correction transfer in an integrated manner. By combining these functions and using the same hardware resources for both purposes, the patent improves image quality through effective dark current correction while minimizing additional processing time.
Data Source
AI summary
A charge transfer implemented by a transfer section for transferring charges stored in image sensor elements along one direction on a surface where the image sensor elements are disposed is halted for a predetermined length of time. The charges are transferred from the transfer section without reading the charges from the image sensor elements after the charge transfer is halted for the predetermined length of time. A position where a defect is generated in an image pickup sensor is identified based on signal levels of the transferred charges. A defective signal level of the image pickup sensor generated on a line including the defect-generating position and in parallel with the one direction is corrected. As a result of the foregoing process, a display failure is precisely corrected.