Time Measurement Device Using Reference Waveform Copying
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Solution Overview
Problem
Existing time measurement devices using the TOF method face challenges in achieving high time measurement accuracy due to various delays within the device.
Innovation Solution
A time measurement device is designed with a first light receiving unit capable of detecting emission pulse light and reflected pulse light, a timing detection unit to measure the light receiving timings, a calculation unit to calculate a time value by subtracting the light receiving timings, and a histogram generation unit to generate a histogram based on the time value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the TOF method is used to measure distance by detecting reflected light, then distance measurement capability is achieved, but time measurement accuracy deteriorates due to various delays within the device
Solution Approach 1:
The patent creates a virtual copy of the light propagation path by generating a reference waveform that simulates the expected reflected light signal. This reference waveform copy allows the system to compare actual measurements against a predetermined model, eliminating the need for complex physical delay compensation mechanisms while maintaining high time measurement accuracy.
Solution Approach 2:
The system performs preliminary actions by pre-calculating and storing reference waveforms that account for various device delays before actual measurement. These reference waveforms are generated in advance based on known device characteristics, allowing the measurement system to compensate for delays without adding complex real-time processing during the actual time-of-flight measurement.
2Measurement precision
If multiple light output pulses are used to improve measurement accuracy, then time measurement accuracy improves, but power consumption increases
Solution Approach 1:
Instead of physically emitting multiple light pulses to improve signal quality, the system creates a virtual copy of the expected signal through reference waveform generation. This computational approach allows the system to achieve accurate measurements by comparing actual signals against pre-generated references, eliminating the need for multiple physical light emissions and thereby reducing power consumption while maintaining measurement accuracy.
3Reliability
If the light receiving unit continuously detects light to improve measurement reliability, then measurement reliability improves, but power consumption increases
Solution Approach 1:
The system implements periodic action by using continuous reference waveform generation and comparison rather than continuous physical light emission and detection. The reference waveform is continuously available for comparison, providing reliable measurement capability on demand without requiring the light receiving unit to remain actively engaged in physical detection, thereby reducing power consumption while maintaining measurement reliability.
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 device enhances measurement accuracy by detecting both reference and reflected pulse lights, allowing for the cancellation of various delays and reducing power consumption by minimizing the number of light output pulses.
Implementation Method 1
a first light receiving unit configured to be able to detect first pulse light and second pulse light
Implementation Method 2
measures a time difference between a timing at which the light is outputted and a timing at which the reflected light is detected, thereby measuring the distance
Data Source
AI summary
A time measurement device according to the present disclosure includes: a first light receiving unit; a first timing detection unit; a first calculation unit; and a histogram generation unit. The first light receiving unit is configured to detect first pulse light and second pulse light. The first pulse light corresponds to emission pulse light emitted from a light emitting unit. The second pulse light includes reflected light by a target object. The reflected light by the target object corresponds to the emission pulse light. The first timing detection unit is configured to detect a first light receiving timing of the first pulse light and a second light receiving timing of the second pulse light by the first light receiving unit on the basis of an output signal of the first light receiving unit. The first calculation unit is configured to calculate a first time value by performing a subtraction process on the basis of the first light receiving timing and the second light receiving timing. The histogram generation unit is configured to generate a histogram on the basis of the first time value.