ToF Distance Measurement Device Stop Control Circuit Power Optimization
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Solution Overview
Problem
Existing Time of Flight (ToF) distance measurement devices face increased power consumption when measuring distances to objects with low reflectance by repeating distance measurement operations to improve reflected light detection accuracy.
Innovation Solution
A distance measurement device with a stop control circuit that generates a stop signal if a predetermined condition is met in multiple detection operations, halting further detection operations in subsequent frames to conserve power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distance measurement operation is repeated multiple times to improve reflected light detection accuracy for low-reflectance objects, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The stop control circuit continuously monitors the signals obtained from detection operations across multiple subframes. When a predetermined condition is satisfied (indicating sufficient detection accuracy has been achieved), the circuit generates a stop signal to halt further detection operations. This feedback mechanism allows the system to automatically determine when enough measurement data has been collected, preventing unnecessary repeated operations and thereby reducing power consumption while maintaining required measurement precision.
Solution Approach 2:
The system dynamically adjusts the number of detection operations based on real-time signal conditions. Instead of performing a fixed number of repeated measurements, the detection operation continues adaptively until the stop control circuit determines the predetermined condition is met. This dynamic control allows the system to reduce the number of operations when high reflectance objects are detected, thus lowering power consumption while ensuring sufficient accuracy for low-reflectance objects when needed.
2Measurement precision
If distance measurement operation is performed multiple times to improve detection accuracy, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The stop control circuit uses feedback from detected signals to determine when sufficient measurement data has been obtained. By monitoring signal characteristics across multiple subframes, the circuit can identify when the predetermined condition is satisfied and generate a stop signal to halt further operations. This feedback-based termination mechanism prevents unnecessary time consumption from repeated measurements while ensuring adequate accuracy has been achieved.
Solution Approach 2:
The detection operation count is dynamically adjusted based on actual signal conditions rather than following a fixed protocol. When objects with high reflectance are detected, the system automatically reduces the number of required measurements, thereby reducing time loss. For low-reflectance objects requiring more measurements, the system continues operations until the predetermined condition is met, optimizing the time spent on measurement.
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 suppresses power consumption while maintaining accurate distance measurement by optimizing detection operations based on signal conditions, particularly for low-reflectance objects.
Implementation Method 1
a plurality of pixels each including a photoelectric conversion element
Data Source
AI summary
A distance measurement device including pixels and a calculator configured to generate distance information based on signals obtained by the pixels is provided. A sequence for generating the distance information includes distance measurement frames, and each of the distance measurement frames includes subframes which are different from each other in a time between light emission by a light source and a period in which a detection operation of detecting light reflected by a target object is performed. The device further comprises a stop controller configured to generate a stop signal if signals obtained by the detection operations respectively performed in the subframes satisfy a predetermined condition. Among the distance measurement frames, in a distance measurement frame after the stop signal is supplied from the stop controller, each of the pixels does not perform the detection operation.