Intrinsic Static Noise Removal in Optical Time-of-Flight Sensors
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Solution Overview
Problem
Current optical time-of-flight sensors face challenges in accurately measuring distances due to intrinsic static noise caused by electrical and optical interference, which degrades measurement accuracy and precision, and existing methods fail to effectively remove this noise.
Innovation Solution
A computer-implemented method and system that uses full-waveform analysis to characterize and remove intrinsic static noise by determining a noise template from calibration traces in a controlled environment and subtracting it from normal operation traces, employing statistical analysis and Gaussian modeling to improve signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hardware electrical isolation techniques are used to reduce crosstalk, then crosstalk reduction is achieved, but device complexity increases and implementation becomes difficult
Solution Approach 1:
The patent replaces hardware electrical isolation techniques with a software-based digital signal processing approach. Instead of using physical shielding and complex circuit configurations to reduce crosstalk, the invention uses digital filtering and signal processing algorithms to eliminate crosstalk from the captured signals, thereby reducing implementation complexity while maintaining effectiveness
Solution Approach 2:
The patent introduces an intermediary processing stage between signal capture and final measurement. A microprocessor or digital signal processor acts as an intermediary to capture the full waveform signals, apply digital filtering to remove crosstalk, and then extract distance measurements, separating the physical sensing from the signal cleanup function
2Device complexity
If software-based digitalization methods are used to minimize crosstalk, then implementation complexity is reduced, but noise in outputted signals remains non-negligible
Solution Approach 1:
The patent changes the parameters of signal processing by using full-waveform analysis instead of traditional time-of-flight measurement. By capturing and analyzing the complete waveform signal rather than just the first return time, the system can apply advanced digital filtering techniques that better preserve signal quality while removing noise, achieving both low complexity and high reliability
Solution Approach 2:
The patent performs preliminary digital filtering and signal processing on the captured waveforms before extracting distance measurements. By preprocessing the signals to remove crosstalk and noise before the measurement extraction step, the system ensures higher signal quality in the final output while maintaining simple overall implementation
3Device complexity
If intrinsic static noise is not removed, then signal processing is simpler, but distance measurement accuracy and precision are significantly degraded
Solution Approach 1:
The patent extracts and removes the intrinsic static noise component from the captured signals through digital signal processing. By identifying and subtracting the characteristic noise pattern from each waveform, the system isolates the true distance measurement information from the noise, significantly improving measurement precision without requiring complex hardware modifications
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 significantly enhances the Signal-to-Noise Ratio (SNR) and accuracy of distance measurements by effectively attenuating intrinsic static noise, leading to improved precision and reliability in optical time-of-flight sensors.
Implementation Method 1
Each emitted light pulse that is backscattered by the objects in the environment of the sensor is captured by a sensor comprising one or an array of photodiodes. The signal generated by each photodiode is amplified and digitalized
Implementation Method 2
determining a noise template using the calibration traces by performing a statistical analysis on the calibration traces to determine a shape and an amplitude of the intrinsic static noise in the calibration traces
Implementation Method 3
subtracting the noise template from the normal operation trace, obtaining and outputting a denoised signal
Data Source
AI summary
A computer-implemented method and a system for at least partially removing intrinsic static noise from data obtained by an optical time-of-flight sensor using full-waveform analysis. The method includes receiving a plurality of calibration traces, the calibration traces being obtained in a controlled environment wherein no object is present in a field of view of the optical time-of-flight sensor; determining a noise template using the calibration traces by performing a statistical analysis on the calibration traces to determine a shape and an amplitude of the intrinsic static noise in the calibration traces; receiving a normal operation trace, the normal operation trace being obtained in an uncontrolled environment wherein a presence of the object in the field of view is unknown; subtracting the noise template from the normal operation trace, obtaining and outputting a denoised signal.