TOF Sensor Waveform Reconstruction via Staggered Pulse Integration
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Solution Overview
Problem
Time-of-flight (TOF) sensors face challenges in accurately reconstructing waveforms for distance measurement using low sampling rates due to limitations in available photo-receivers and readout circuits, which require high-speed sampling for accurate distance estimation.
Innovation Solution
The TOF sensor employs a method of emitting a train of light pulses and integrating electrical outputs over controlled integration periods, with each accumulation cycle's start time delayed relative to the previous, allowing for accurate waveform reconstruction at a lower sampling rate by calculating sample points from the differences between consecutive accumulation values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-speed sampling is used for accurate distance measurement, then measurement precision is improved, but device complexity and cost increase due to requirements for high-speed photo-receivers and readout circuits
Solution Approach 1:
The patent divides the waveform reconstruction process into multiple accumulation cycles, where each cycle captures a portion of the reflected light pulse. By segmenting the measurement into discrete time intervals and accumulating results, the system achieves high measurement precision without requiring high-speed sampling hardware.
Solution Approach 2:
The patent performs preliminary accumulation of light pulse signals over multiple cycles before final waveform reconstruction. By pre-integrating the optical signals and storing accumulation values, the system prepares processed data in advance, eliminating the need for high-speed real-time sampling during the actual measurement.
2Device complexity
If low sampling rate is used to reduce device complexity, then device complexity is reduced, but measurement precision deteriorates due to insufficient sampling for accurate waveform reconstruction
Solution Approach 1:
The patent employs periodic accumulation cycles that systematically sample the reflected light pulse at regular intervals. By repeating the accumulation process multiple times with controlled timing, the system reconstructs the complete waveform using low-rate sampling, achieving both reduced device complexity and maintained measurement precision.
Solution Approach 2:
The patent creates multiple copies of the accumulation process across different time cycles, where each cycle captures a portion of the waveform. By combining these replicated measurements, the system reconstructs the complete high-fidelity waveform without requiring high-speed sampling hardware.
3Measurement precision
If multiple accumulation cycles with delayed start times are used for waveform reconstruction, then measurement precision is improved through better sampling coverage, but loss of time increases due to multiple cycles required
Solution Approach 1:
The patent dynamically adjusts the start time of each accumulation cycle relative to the previous cycle, creating a staggered sampling pattern. This dynamic timing arrangement ensures optimal coverage of the reflected light pulse waveform across all cycles, maximizing measurement precision while minimizing the total time required.
Solution Approach 2:
The patent maintains continuous accumulation of optical signals across multiple cycles without idle periods. By continuously integrating the photo-receiver output and systematically progressing through delayed start times, the system maximizes the useful measurement action throughout the entire multi-cycle process, reducing overall 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 accurate distance measurement and waveform reconstruction using a relatively low sampling rate, overcoming the limitations of existing technologies by effectively interpolating sampled values to reconstruct the reflected light pulse waveform.
Implementation Method 1
a photo-receiver configured to generate an electrical output proportional to an intensity of light incident on a surface of the photo-receiver
Implementation Method 2
time-of-flight (TOF) sensors capable of accurately reconstructing a waveform for a reflected light pulse
Data Source
AI summary
A time-of-flight (TOF) sensor device is configured to perform classification analytics on a waveform signal representing a reflected light pulse, and to classify an object from which the light pulse was received based on characteristic properties of the reflected pulse. The TOF sensor device can compare the reflected pulse waveform with stored characteristic waveform profiles indicative of different types of objects or atmospheric particulates, including but not limited to snow, aerosol, water, fog, or mist. Some embodiments of TOF sensor device can also detect excessive levels of mist or suspended particulates that may reduce the detection accuracy of the sensor. To this end, such embodiments project focused light beams according to a defined pattern, and compare the reflected pattern with the defined pattern to determine a degree of pattern distortion attributable to the presence of mist.