ToF Sensor Segmentation for Frame Rate and Background Light
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Solution Overview
Problem
Existing indirect-ToF measurement apparatuses face challenges in improving frame rate due to the reduction in measurable regions for a single light emission, caused by the exposure period for detecting background light.
Innovation Solution
A measurement apparatus with a sensor that includes a light-receiving element and multiple accumulation portions, a signal acquisition unit to acquire signal values, and a correction unit to identify and correct signal values based on the minimum signal value, allowing for improved frame rate while suppressing background light influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an exposure period for detecting background light is provided before light emission, then the influence of background light is suppressed, but the measurable region for a single light emission is reduced and frame rate cannot be improved
Solution Approach 1:
The sensor is divided into multiple accumulation portions (first, second, third accumulation portions) that independently accumulate charge from the light-receiving element. Each accumulation portion stores charge from different time periods, allowing parallel processing of multiple measurement regions without requiring sequential background light detection periods.
Solution Approach 2:
The system uses periodic light emission and synchronized periodic exposure in multiple accumulation portions. By coordinating the exposure timing of different accumulation portions with the periodic light emission, the system measures multiple regions simultaneously at different time points within each emission cycle, eliminating the need for separate background light exposure periods.
2Productivity
If multiple regions are measured for a single light emission to improve frame rate, then productivity increases, but the ability to suppress background light influence deteriorates
Solution Approach 1:
The sensor is divided into multiple accumulation portions (first, second, third accumulation portions) that independently accumulate charge from the light-receiving element. Each accumulation portion stores charge from different time periods, allowing parallel processing of multiple measurement regions without requiring sequential background light detection periods.
Solution Approach 2:
The correction unit uses feedback from the minimum signal value (obtained from accumulation portions measuring only background light) to correct signal values from other accumulation portions. This feedback mechanism allows simultaneous measurement of multiple regions while maintaining background light suppression through mathematical correction based on the minimum value feedback.
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 effectively improves the frame rate by allowing multiple regions to be measured for a single light emission, while maintaining the suppression of background light influence.
Implementation Method 1
a light-receiving element configured to generate charge according to an exposure amount
Data Source
AI summary
A measuring device includes a sensor including a light-receiving element configured to generate charge according to an exposure amount and a plurality of accumulation portions configured to accumulate charge distributed according to an exposure period; a signal acquisition unit configured to acquire signal values corresponding to the charge of the plurality of accumulation portions, respectively; and a correction unit configured to identify a minimum signal value that indicates the smallest exposure amount from among the plurality of signal values and to correct the signal value based on the minimum signal value.