Photoelectric Sensor Array Dynamic Range via Global Shutter Readout
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Solution Overview
Problem
Existing photoelectric sensor arrays face challenges in managing different image areas with varying brightness values, as prior methods require significant computing power and hardware complexity to achieve high dynamic range, making them unsuitable for cost-effective and complex applications like motor vehicle camera systems.
Innovation Solution
The method involves dividing the sensor array into non-overlapping regions of interest with individual exposure times, using a global shutter device to pause exposure during readouts, allowing for selective reading of image areas without resetting the entire array, thereby simplifying the architecture and reducing computational demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire sensor array is read out sequentially with uniform exposure time, then the readout process is simple, but the dynamic range between different brightness areas is limited
Solution Approach 1:
The sensor array is divided into multiple independent readout regions (first readout region and second readout region), each with its own exposure time control. This segmentation allows different exposure times for different brightness areas without requiring complex global control mechanisms, thus improving dynamic range while maintaining manageable system complexity.
Solution Approach 2:
Different regions of the sensor array are assigned different exposure times based on their local brightness characteristics. Brighter regions use shorter exposure times to avoid saturation, while darker regions use longer exposure times to capture sufficient signal, optimizing the dynamic range for each local area.
2Measurement precision
If multiple readout regions with different exposure times are implemented, then the dynamic range is improved, but the readout time increases
Solution Approach 1:
The exposure pause is strategically positioned after the first readout region is read out but before the second readout region is read out. This preliminary action allows the first region to be captured with its optimal exposure time while the second region continues accumulating light, enabling parallel exposure accumulation that reduces total readout time.
Solution Approach 2:
While the first readout region is being read out during the exposure pause, the second readout region continues to accumulate light without interruption. This continuous useful action ensures that no exposure time is wasted, and both regions contribute to the final image simultaneously, minimizing overall acquisition time.
3Ease of operation
If the sensor array is reset after each readout, then the pixels are ready for next exposure, but the exposure continuity is interrupted
Solution Approach 1:
The sensor array is segmented into multiple readout regions that can be read out at different times. This segmentation allows the exposure process to be divided into separate phases, with each region being read out independently, maintaining exposure continuity for regions that have not yet been read out.
Solution Approach 2:
The exposure process is made dynamic by allowing different regions to be at different stages of the exposure cycle simultaneously. Some regions may be in the middle of exposure while others are being read out, creating a flexible, adaptive exposure system that maintains overall continuity.
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 approach enhances the dynamic range between image areas without adding hardware complexity or high computing power, offering a time advantage in image acquisition by optimizing readout processes based on the longest exposure time and individual sub-area readout times.
Implementation Method 1
photoelectric converter elements which form individual pixels and which, when exposed to light, emit an electrical signal corresponding to the light intensity and the exposure time
Data Source
AI summary
The invention relates to a method for the operation of a photoelectric sensor array, comprising a two-dimensional arrangement of a plurality of freely addressable and readable photoelectric converter elements forming single image points. When applying light, the converter elements generate an electric signal corresponding to the light strength and the exposure time. The invention further relates to a global closure device for controlling the exposure of the converter elements, characterized by the exposure of the converter elements being interrupted after a first exposure time by the global closure device for the length of a exposure break. During the exposure break, single converter elements are read. The exposure is continued for the length of a second exposure time, without erasing the content of the converter elements.