LiDAR Pulse Peak Correction for Walk Error Accuracy
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Solution Overview
Problem
Lidar systems suffer from walk error, which adversely affects their accuracy, particularly for targets within a certain range, due to shifts in the peak location of received laser pulses.
Innovation Solution
A method for walk error correction in lidar systems involves comparing a preliminary peak location to a threshold, determining a pulse starting point by locating consecutive increasing intensity values, and calculating a corrected peak location using the total rise time of the laser pulse to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional peak detection methods are used in lidar systems, then the system operation is simple, but measurement precision deteriorates due to walk error
Solution Approach 1:
The patent applies preliminary action by detecting consecutive increasing intensity values before determining the peak location. This preliminary detection of the rising edge pattern allows the system to identify and correct walk error before final distance calculation, thereby improving measurement precision without requiring complex hardware modifications
Solution Approach 2:
The patent creates a corrected peak location by copying and adjusting the detected peak position based on the walk error correction algorithm. Instead of directly using the raw peak detection result, the system generates a corrected version that compensates for walk error, improving accuracy while maintaining computational efficiency
2Measurement precision
If walk error correction is applied to all targets, then measurement precision improves, but use of energy increases
Solution Approach 1:
The patent applies local quality by implementing selective walk error correction based on target distance. The system determines whether correction is needed by evaluating the preliminary peak location and comparing it with expected values, applying correction only when necessary (for nearby targets), thereby improving energy efficiency while maintaining measurement precision where it matters most
Solution Approach 2:
The patent changes the operational parameters dynamically by adjusting whether walk error correction is applied based on the detected peak location and target distance. This conditional parameter change allows the system to optimize energy consumption by enabling correction only in scenarios where walk error significantly impacts accuracy
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 method significantly enhances the accuracy of lidar systems by correcting walk error, especially for targets within a predetermined threshold distance, by accurately determining the peak location and time of flight.
Implementation Method 1
The avalanche photodiodes are photodiodes with a structure optimized for operating with high reverse bias, approaching the reverse breakdown voltage. This allows each photo-generated carrier to be multiplied by avalanche breakdown, resulting in internal gain within the photodiode
Implementation Method 2
When a photon of sufficient energy strikes the diode, it creates an electron-hole pair. This mechanism is also known as the inner photoelectric effect.
Implementation Method 3
A corrected peak location is obtained using the pulse staring point, and it is used for time of flight calculation
Data Source
AI summary
A method for walk error correction in a lidar system. A preliminary peak location of a received laser pulsed is compared to a threshold. If the preliminary peak location is within the threshold, walk error correction is applied. A pulse starting point is obtained by locating a predetermined number of consecutive increasing intensity values. A corrected peak location is obtained using the pulse staring point, and it is used for time of flight calculation. There are other embodiments as well.