Micro-frame Exposure Control for Distance Resolution and Frame Rate
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Solution Overview
Problem
Existing distance measurement apparatuses face a tradeoff between distance resolution and frame rate due to the Time-gate method used in United States Patent Application Publication No. 2017/0052065.
Innovation Solution
The proposed apparatus includes a pixel array with a photoelectric conversion element, multiple readout units, and addition units to acquire and synthesize micro-frames with different exposure periods, allowing for the generation of sub-frames and improving the frame rate while maintaining distance resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Time-gate method is used to measure distance by repeatedly performing measurement while varying a gating period, then distance resolution is improved, but frame rate deteriorates
Solution Approach 1:
The patent divides the frame into multiple micro-frames with different exposure periods. Each micro-frame captures light signals at different time gates, allowing the system to obtain multiple distance measurements within a single frame period. This segmentation enables parallel processing of distance measurements at different resolution levels without sequentially waiting for each measurement to complete, thus improving frame rate while maintaining distance resolution.
Solution Approach 2:
The patent introduces a temporal dimension by varying exposure periods across multiple micro-frames within the same frame. Instead of sequentially performing measurements one after another (time dimension), the system performs measurements simultaneously at different exposure periods (parallel time dimension), effectively adding a dimension to the measurement process that resolves the tradeoff between resolution and frame rate.
2Measurement precision
If the gating period is varied to improve distance resolution, then measurement precision is improved, but the time required for measurement increases
Solution Approach 1:
The patent performs preliminary actions by capturing light signals at multiple different exposure periods simultaneously within the same frame. Instead of waiting for a single long measurement to complete, the system preliminarily captures signals at shorter exposure periods and combines them to achieve the desired resolution. This allows the system to prepare multiple measurement components in parallel rather than sequentially.
Solution Approach 2:
The patent maintains continuous useful action by keeping the photoelectric conversion element active across multiple micro-frames with different exposure periods. Rather than having the element idle between sequential measurements, the system continuously captures signals at varying exposure periods, ensuring that the measurement process is ongoing and productive throughout the frame period, thereby reducing total measurement time.
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 enables an increased frame rate without compromising distance resolution, effectively addressing the tradeoff inherent in previous methods.
Implementation Method 1
a pixel array in which a plurality of pixels including a photoelectric conversion element is arranged in an array
Data Source
AI summary
An apparatus includes a pixel array in which a plurality of pixels including a photoelectric conversion element is arranged, a first readout unit for acquiring a first micro-frame, a second readout unit for acquiring a second micro-frame, a first addition unit for generating a first sub-frame by synthesizing the first micro-frame, and a second addition unit for generating a second sub-frame by synthesizing the second micro-frame, in which a first exposure period in which generation of a signal included in the first micro-frame is performed is controlled in accordance with a first control signal, a second exposure period in which generation of a signal included in the second micro-frame is performed is controlled in accordance with a second control signal, and in an acquisition period of one micro-frame, the first exposure period and the second exposure period differ from each other.