Multi-Pulse Optical Rangefinder Temporal Slippage Correction
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Solution Overview
Problem
Current optical rangefinder instruments, such as mechanical scanners and 3D flash lidars, fail to meet industry requirements for performance, reliability, and cost in autonomous driving applications, particularly under varying lighting and environmental conditions.
Innovation Solution
A method and system for optically scanning a region using a pulsed light source and photodetector, where an interleave sequence defines the scanning order, allowing for sequential propagation of optical pulses and detection of pulse echoes, with a correction mechanism to account for vehicle displacement and temporal slippage, enhancing the accuracy and range of detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical scanners are used for optical scanning, then the system can perform scanning function, but the performance, reliability and cost do not meet industry requirements
Solution Approach 1:
The patent replaces mechanical scanning mechanisms with a solid-state optical scanning system that uses electronic control to direct optical pulses. The controller electronically steers the scanning directions without mechanical moving parts, thereby improving reliability and reducing complexity while maintaining scanning functionality.
Solution Approach 2:
The system employs periodic optical pulse emission combined with interleaved scanning directions. By emitting multiple pulses at different times and scanning in alternating directions, the system achieves comprehensive coverage without mechanical movement, resolving the contradiction between reliability and complexity.
2Length of stationary object
If 3D flash lidars are used, then the system can provide wide field of view, but the range is limited and cost is very high
Solution Approach 1:
The patent segments the scanning process into multiple discrete scanning directions with interleaved pulse emission. By dividing the field of view into multiple directional segments and systematically scanning through them, the system achieves extended effective range while maintaining manageable system complexity through software-controlled scanning paths.
Solution Approach 2:
The controller pre-calculates and stores multiple scanning directions in advance, allowing the system to efficiently sweep through the field of view without real-time computational overhead. This preliminary preparation enables extended scanning range while keeping the system relatively simple.
3Measurement precision
If optical pulses are emitted sequentially in different scanning directions, then the non-ambiguous range is improved, but the time required for scanning increases
Solution Approach 1:
The system uses periodic pulse emission with interleaved scanning directions, where multiple scanning directions are processed in alternating time periods. This allows the system to achieve precise range measurements across multiple directions while managing scanning time through efficient temporal multiplexing of the scanning sequence.
Solution Approach 2:
The controller continuously emits optical pulses in different scanning directions without idle time between directional scans. By maintaining continuous useful action through overlapping pulse emission and scanning, the system minimizes total scanning time while preserving measurement precision across all scanning directions.
4Adaptability or versatility
If the vehicle moves during pulse emission, then the system can detect objects in motion, but temporal slippage occurs that reduces detection accuracy
Solution Approach 1:
The system incorporates feedback mechanisms where the controller receives position information about the vehicle and adjusts the timing of optical pulse emission accordingly. This feedback loop compensates for temporal slippage caused by vehicle motion, maintaining detection accuracy while preserving the ability to detect moving objects.
Solution Approach 2:
The controller pre-adjusts the emission timing of optical pulses based on predicted vehicle position and motion. By performing preliminary timing corrections before pulse emission, the system compensates for anticipated temporal slippage due to vehicle movement, maintaining both motion detection capability and detection 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 solution provides a robust and efficient optical rangefinder system that improves the non-ambiguous range of detection and signal-to-noise ratio, addressing the limitations of existing technologies by optimizing scanning directions and correcting for temporal discrepancies, thereby enhancing the system's performance and reliability in autonomous driving environments.
Implementation Method 1
a pulsed light source for sequentially propagating optical pulses according to the interleave sequence
Implementation Method 2
detecting pulse echoes corresponding to a reflection of the propagated optical pulses on at least one object present within the region
Data Source
AI summary
There is provided a method for optically scanning a region according to a plurality of scanning directions, comprising: receiving an interleave sequence defining a scanning order for the plurality of scanning directions; sequentially propagating optical pulses according to the interleave sequence; detecting pulse echoes corresponding to a reflection of the propagated optical pulses on at least one object present within the region; and outputting the detected pulse echoes. There is further described a computer-implemented method for correcting a temporal slippage of an optical echo.