Rolling Shutter Sensor Partial Readout Charge Time Control
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Solution Overview
Problem
Image pickup apparatuses with rolling shutter type CMOS sensors face challenges in maintaining exposure quality and reducing image quality deterioration when changing the interest area settings, particularly in high-pixel count scenarios, leading to decreased frame rates and increased inspection times in machine vision applications.
Innovation Solution
An image pickup apparatus with a readout condition setter, charge time setter, and controller that allows for constant charge time and reduced image quality deterioration by selectively reading out pixel data from a partial area of the sensor, ensuring consistent exposure regardless of interest area changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If partial readout is implemented to increase frame rate, then productivity improves, but exposure quality deteriorates due to charge time shortening
Solution Approach 1:
The patent divides the pixel array into multiple independent readout channels, allowing parallel readout of different regions. This segmentation enables the charge time to be maintained for the entire sensor area while the readout time is reduced by processing multiple regions simultaneously through different channels, thus resolving the contradiction between maintaining exposure quality and increasing frame rate.
Solution Approach 2:
The patent implements preliminary charge accumulation for the entire pixel array before readout begins. By completing the photoelectric conversion process for all pixels first, then initiating parallel readout operations, the system ensures that exposure quality is not compromised while maximizing the subsequent readout speed through pre-synchronized multi-channel processing.
2Productivity
If interest area is reduced to shorten inspection time, then productivity improves, but image quality deteriorates due to post-processing requirements
Solution Approach 1:
The patent extracts and processes only the necessary pixel data from the full sensor array through selective readout channels. By reading out only the relevant regions of interest while maintaining full sensor exposure, the system reduces data processing requirements and inspection time without compromising the quality of the captured images in the interest areas.
Solution Approach 2:
The patent applies different readout strategies to different regions of the sensor, optimizing the readout process for specific areas of interest while maintaining full exposure across the entire sensor. This local optimization allows faster processing of critical regions without sacrificing image quality in those areas.
3Manufacturing precision
If full pixel array is read out to maintain image quality, then manufacturing precision improves, but readout time increases reducing productivity
Solution Approach 1:
The patent implements continuous parallel readout operations across multiple channels simultaneously. While one channel is reading out data from one region, other channels are concurrently reading from different regions, ensuring that the readout process continues without interruption and maximizes throughput while maintaining full sensor utilization for image quality.
Solution Approach 2:
The patent segments the readout process into multiple parallel channels that operate simultaneously. This allows the full pixel array to be read out through distributed channels, maintaining complete image quality data while reducing the time each individual channel needs to operate, thus resolving the contradiction between comprehensive readout and readout speed.
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
The solution enables maintaining exposure quality and reducing image quality deterioration even when changing interest area settings, thereby improving frame rates and shortening inspection times in machine vision applications.
Implementation Method 1
charge processing for photoelectric conversion and readout processing of a photoelectrically converted signal
Data Source
AI summary
Provided is an image pickup apparatus capable of reading out and outputting pixel data of a partial area of a rolling shutter type image sensor. The image pickup apparatus includes: a readout condition setter configured to set a readout condition from the image sensor; a charge time setter configured to set charge time of the image sensor; a controller configured to control charging of the image sensor and readout from the image sensor so as to achieve constant charge time irrespective of the readout condition; and an image signal output unit configured to output a pixel signal read out by the controller.