ToF Light Receiving Timing Correction for Noise-Stable Ranging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Variations in the input timing of feedback signals due to noise affect the accuracy of ranging in direct Time of Flight (ToF) techniques.
Innovation Solution
A light receiving apparatus with a light receiving unit, a light emission control unit, a delay acquiring unit, and a signal processing unit that corrects light emission timing using a representative value of acquired delay times to improve ranging accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the direct ToF technique is used for ranging, then ranging capability is achieved, but noise causes variations in feedback signal timing that reduce measurement accuracy
Solution Approach 1:
The system performs preliminary delay measurements multiple times before the actual ranging measurement. By acquiring delay times in advance (preliminary action) and calculating a representative value, the system prepares correction data that compensates for timing variations caused by noise, thereby improving the reliability of the feedback signal timing for the actual measurement.
Solution Approach 2:
The system measures the delay time of the feedback signal multiple times and uses the representative value (average or median) as a correction parameter. This feedback mechanism allows the system to continuously monitor and compensate for timing variations, improving measurement precision by actively correcting for noise-induced deviations in feedback signal timing.
2Measurement precision
If multiple delay measurements are performed to reduce noise impact, then measurement accuracy improves, but measurement time increases
Solution Approach 1:
The system performs a predetermined number of delay measurements (excessive action) to ensure sufficient statistical reliability for calculating the representative value. By performing more measurements than the absolute minimum, the system achieves better noise rejection and more accurate delay characterization, justifying the additional time investment through improved measurement precision.
Solution Approach 2:
The multiple delay measurements are performed as a preliminary step before the actual ranging measurement. This preliminary characterization of the delay time allows the system to establish a accurate correction parameter in advance, so that the actual ranging measurement can be performed quickly with high precision without needing to repeat multiple measurements during the critical measurement phase.
Data Source
AI summary
A light receiving apparatus according to an embodiment includes: a light receiving unit that includes a light receiving element, a light emission control unit that issues a trigger for causing a light source to emit light, a receiving unit that receives, from a light source unit that includes the light source, a feedback signal that is output in accordance with a light emission timing at which the light source emits the light, a delay acquiring unit that acquires delay time of a reception timing at which the feedback signal is received by the receiving unit is delayed relative to an issue timing at which the trigger is issued, and a representative value acquiring unit that acquires a representative value of a plurality of pieces of the delay time in accordance with the issue of the triggers issued by the light emission control unit a predetermined number of times.