Imaging Device Offset Correction via Segmented Optical Black Regions
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Solution Overview
Problem
Existing imaging devices struggle to perform accurate offset correction when exposure times differ across multiple imaging regions, leading to reduced accuracy in pixel signal offset correction.
Innovation Solution
The imaging device includes a pixel unit with effective and optical black pixels arranged on different rows, where the number of optical black pixels exceeds effective pixels on a row, and employs distinct exposure times for different imaging regions and their associated reference regions to enable appropriate offset correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single optical black region is used for offset correction, then the device complexity is reduced, but the measurement precision deteriorates when exposure times differ across imaging regions
Solution Approach 1:
The optical black region is segmented into multiple reference regions (first reference region and second reference region), each corresponding to different imaging regions with different exposure times. This segmentation allows independent offset correction for each imaging region, resolving the contradiction by maintaining simple overall structure while achieving region-specific precision.
Solution Approach 2:
Each reference region is configured with local characteristics matching its corresponding imaging region's exposure time. The first reference region uses a first exposure time for the first imaging region, while the second reference region uses a second exposure time for the second imaging region. This local quality approach ensures accurate offset correction without requiring complex global synchronization.
2Measurement precision
If the number of optical black pixels is increased to improve offset correction accuracy, then the measurement precision improves, but the area occupied by non-effective pixels increases
Solution Approach 1:
The optical black pixels are segmented into multiple reference regions distributed across different rows. Each reference region contains a manageable number of pixels sufficient for accurate offset correction of its corresponding imaging region. This segmentation achieves the required measurement precision without requiring a single large optical black region, thus optimizing the area utilization.
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
This configuration allows for precise offset correction across imaging regions with varying exposure times, enhancing the accuracy of pixel signal processing and reducing errors due to exposure time differences.
Implementation Method 1
each of the plurality of pixels includes a photoelectric converter
Data Source
AI summary
An embodiment includes: a pixel unit including first and second imaging regions arranged with effective pixels and first and second reference regions arranged with optical black pixels; and a scanning unit that performs, on a row-by-row basis, reset operations of photoelectric converters and readout operations of pixel signals based on charges generated in the photoelectric converters which includes charge transfer to transfer charges generated in the photoelectric converters to holding portions. The scanning unit drives the pixels in the first imaging region and the first reference region in a first condition where a period from the end of reset operation to the end of charge transfer is a first length and drives the pixels in the second imaging region and the second reference region in a second condition where a period from the end of reset operation to the end of charge transfer is a second length.