Dual-Sensitivity Pixel Structure for Single-Exposure HDR Sensing
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Solution Overview
Problem
Conventional image sensors have a limited dynamic range, making it difficult to capture both low-light and high-brightness information simultaneously, which can lead to misjudgments in environments like traffic sign recognition, especially in the presence of flickering lights.
Innovation Solution
A pixel structure comprising both high-sensitivity first pixels and low-sensitivity second pixels, arranged in an array, with independent output circuits to separately handle low-light and high-brightness information, allowing for improved dynamic range and reliable recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a standard image sensor with single pixel is used, then the device complexity is low, but the dynamic range is limited and cannot capture both low-light and high-brightness information simultaneously
Solution Approach 1:
The pixel array is segmented into two distinct types: first pixels with high-sensitivity photoelectric conversion elements for capturing low-light information, and second pixels with low-sensitivity photoelectric conversion elements for capturing high-brightness information. This segmentation allows each pixel type to be optimized for specific lighting conditions, thereby expanding the overall dynamic range of the image sensor.
Solution Approach 2:
Different regions of the pixel array are assigned different photoelectric conversion element characteristics. The first pixels use high-sensitivity elements (larger area) optimized for low-light conditions, while the second pixels use low-sensitivity elements (smaller area) optimized for high-brightness conditions. This local differentiation enables the sensor to adapt to varying light conditions across different spatial locations.
2Adaptability or versatility
If multiple exposure images are combined to increase dynamic range, then the dynamic range is improved, but the loss of time increases due to multiple exposures
Solution Approach 1:
Instead of sequentially capturing multiple exposure images, the system segments the pixel array into simultaneous capture units. First pixels and second pixels operate concurrently during a single exposure interval, with each pixel type capturing information optimized for its sensitivity range. This eliminates the time loss associated with sequential multi-exposure techniques while achieving HDR capability.
Solution Approach 2:
The image sensor maintains continuous useful action by having both first and second pixels actively capturing images during the same exposure period. This parallel operation ensures that no time is lost to sequential processing, and the useful action of light capture continues uninterrupted across the full dynamic range.
3Reliability
If a single pixel is used for traffic sign recognition, then the device complexity is low, but the reliability decreases due to inability to recognize both low-light and high-brightness information
Solution Approach 1:
The pixel array is segmented into specialized first pixels and second pixels that can simultaneously detect different brightness levels of traffic signs. This segmentation enables reliable recognition whether the traffic sign appears in low-light conditions (captured by first pixels) or high-brightness conditions with flickering lights (captured by second pixels), significantly improving recognition reliability.
Solution Approach 2:
Different pixel regions are optimized for different recognition scenarios. The high-sensitivity first pixels are optimally positioned and configured for detecting dim traffic signs in low-light environments, while the low-sensitivity second pixels are optimized for detecting bright traffic signs under normal or flickering light conditions, ensuring reliable recognition across all lighting scenarios.
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 compatible recognition of low-light and high-brightness information, enhancing the dynamic range and recognition accuracy of image sensors, particularly in challenging environments with flickering lights.
Implementation Method 1
each of the first pixels includes: a first photoelectric conversion element... each of the second pixels includes: a second photoelectric conversion element
Data Source
AI summary
The present application provides a pixel structure, an image sensor, a device, an image processing method and a control method. The pixel structure includes a plurality of first pixels and a plurality of second pixels, where the first pixels adopt first photoelectric conversion elements arranged in an array and provided with high sensitivity, and the second pixels adopt second photoelectric conversion elements arranged in an array and provided with low sensitivity, to realize compatible recognition of high-brightness information and low-light information by the image sensor and improving the dynamic range; the first photoelectric conversion elements and the second photoelectric conversion elements adopt a design of independent output circuits to realize separate output of electrical signals without interfering with each other, which improves recognition reliability and signal utilization recognition; the overall performance of the image sensor can also be improved based on layout of the pixel structure of the present application.