Image Sensor Pixel Storage for Buffer-Free Dual-Exposure Capture
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Solution Overview
Problem
Current image sensors for self-driving cars, such as those used in dynamic vision sensors, require digital frame buffers which increase volume and cost, and are prone to errors due to sudden changes in illumination levels, leading to inaccurate object detection and increased accident risk.
Innovation Solution
An image sensing device with an image sensing array, conversion unit, and processing circuit that generates and stores sensing signals of different periods or exposure times without the need for a digital frame buffer, allowing for dynamic event detection and exposure fusion to enhance image clarity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a digital frame buffer is added to store sensing signals, then the image sensor can maintain signal storage capability, but the volume and cost of the device increase
Solution Approach 1:
The patent merges the signal storage function into the existing pixel array structure by using dual photoelectric conversion units within each pixel. The first and second storage circuits are integrated alongside the photoelectric conversion units, eliminating the need for separate digital frame buffer memory. This integration maintains signal storage capability while significantly reducing device volume.
Solution Approach 2:
The pixel structure is designed to perform multiple functions: the first photoelectric conversion unit captures images during normal illumination, while the second photoelectric conversion unit captures images during overexposure conditions. The storage circuits serve both as temporary buffers and as part of the dual-exposure imaging system, reducing the need for additional dedicated storage components.
2Quantity of substance
If a digital frame buffer is added to store sensing signals, then the image sensor can maintain signal storage capability, but the manufacturing cost increases
Solution Approach 1:
The patent merges the signal storage function into the existing pixel array structure by using dual photoelectric conversion units within each pixel. The first and second storage circuits are integrated alongside the photoelectric conversion units, eliminating the need for separate digital frame buffer memory. This integration maintains signal storage capability while significantly reducing device volume.
3Device complexity
If the image sensor uses a single exposure time, then the device structure is simple, but the accuracy of object detection in varying light conditions deteriorates
Solution Approach 1:
The patent implements a dynamic dual-exposure imaging system where the second photoelectric conversion unit is activated based on illumination conditions. When overexposure is detected, the system dynamically switches to using the second unit with a longer exposure time, allowing accurate capture of images in varying light conditions while maintaining a relatively simple overall device structure.
Solution Approach 2:
The system changes the exposure time parameter dynamically by using two different photoelectric conversion units with different exposure characteristics. The first unit uses a shorter exposure time for normal conditions, while the second unit uses a longer exposure time for overexposure conditions, thereby maintaining object detection accuracy across varying illumination levels.
4Measurement precision
If the image sensor captures images during overexposure, then the image clarity improves, but the risk of incorrect object detection due to illumination changes increases
Solution Approach 1:
The patent implements a dynamic dual-exposure imaging system where the second photoelectric conversion unit is activated based on illumination conditions. When overexposure is detected, the system dynamically switches to using the second unit with a longer exposure time, allowing accurate capture of images in varying light conditions while maintaining a relatively simple overall device structure.
Solution Approach 2:
The system uses feedback from illumination level detection to determine when to switch between the first and second photoelectric conversion units. When overexposure conditions are detected, the feedback mechanism activates the second unit with adjusted exposure parameters, ensuring reliable object detection despite rapid illumination changes.
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 solution reduces the space and cost of image sensors by eliminating the need for digital frame buffers and improves the accuracy of object detection in varying light conditions, reducing the risk of accidents by enhancing image clarity and brightness.
Implementation Method 1
A sensing circuit of the image sensing structure generates a plurality of sensing signals
Data Source
AI summary
The present invention relates to an image sensing device, including: an image sensing array, a conversion unit, and a processing circuit. The image sensing array is used to generate sensing signals of different periods. The conversion unit is used to convert the sensing signals from analog to digital. The processing circuit is used to generate a frame during an image capturing operation. The image sensing array includes a plurality of sensing sub-pixels, and the sensing sub-pixels have a sensing circuit and a storage circuit. The sensing circuit generates the sensing signals and sequentially stores the sensing signal in the storage circuit. The storage circuit sequentially outputs the sensing signals to the conversion unit.