Multiple-Detector LiDAR Array With Time-Shifted Pulse Sampling
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Solution Overview
Problem
Current LiDAR systems face limitations in precision, throughput, and resolution, particularly for applications like autonomous vehicle navigation and high-frequency feature extraction, due to low incident laser power, rotating scan heads, crosstalk issues, and limited angular direction measurements.
Innovation Solution
LiDAR systems utilize a detector array and a graphics processing unit (GPU) to analyze reflected light packets, employing multiple frame buffers and techniques like segmentation, edge and corner feature detection, and volumetric analysis to enhance precision and resolution, while accounting for environmental factors and manufacturing variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If flash LiDAR illuminates an entire 2D field of view with a blanket of light to simultaneously measure return values, then spatial coverage is improved, but incident laser power per location becomes insufficient for long-range applications
Solution Approach 1:
The patent divides the field of view into multiple angular sectors and uses a rotating polygonal mirror to sequentially scan different portions of the field of view. This segmentation allows concentrated laser power to be directed at each angular position in sequence, maintaining sufficient power density for long-range detection while covering the entire 2D field of view over time.
Solution Approach 2:
The system employs periodic scanning with a rotating polygonal mirror that cycles through different angular positions. By repeatedly scanning the same angular positions over multiple periods, the system accumulates sufficient incident laser power at each location while maintaining continuous coverage of the entire field of view across scanning cycles.
2Productivity
If scanning-type LiDAR uses a rotating mirror to emit light pulses in rapid succession, then measurement speed is improved, but mechanical complexity and reliability deteriorate
Solution Approach 1:
The patent replaces the rotating polygonal mirror with a stationary diffractive optical element or phased array that electronically or optically steers the laser beam across different angular positions. This substitution eliminates moving parts while maintaining the ability to rapidly scan the field of view, thereby improving reliability and reducing mechanical complexity while preserving high measurement throughput.
3Measurement precision
If multiple detectors are used to increase spatial resolution, then measurement precision is improved, but crosstalk between detectors increases
Solution Approach 1:
The patent introduces optical isolators, beam dumps, or spatial filtering elements positioned between the scanning beam path and the detector array. These intermediary components prevent stray light from one angular position from reaching detectors intended for other positions, thereby reducing crosstalk while maintaining the benefits of multiple detectors for high spatial resolution.
4Difficulty of detecting and measuring
If phase shift analysis is used for object detection, then detection capability is improved, but measurement of multiple features per light packet is limited
Solution Approach 1:
The patent employs continuous-wave laser illumination combined with temporal gating or time-correlated single-photon counting to measure multiple features (such as range, velocity, and surface characteristics) from the same light packet. By continuously illuminating the target and analyzing different temporal or spectral components of the return signal, the system extracts multiple features without requiring separate light packets for each measurement.
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 increases device throughput, improves spatial accuracy and resolution, enabling better object identification and feature extraction, particularly in real-time applications such as autonomous vehicle navigation.
Implementation Method 1
the reflected versions of said light are sampled by the detector array
Implementation Method 2
LiDAR (light detection and ranging) uses laser technology to make precise distance measurements
Data Source
AI summary
Methods, systems, and computer program products for acquiring three-dimensional LiDAR information of a scene are disclosed. According to one aspect, acquiring three-dimensional information includes emitting N pulses in a sequence with each successive pulse having a relative time shift to the sampling reference, thus producing a reconstructed sampled signal with an effective sampling rate of N times the sampling reference. According to another aspect, acquiring three-dimensional information includes emitting two or more frequencies, the differences of each pair of differing frequencies being designated as Δf, and sampling the return information with the use of a sampling reference. Frequency analysis is performed on the sampled information to determine the reference times at which the Δf signals occur and the signal intensity of the Δf signals at each time. Systems as described herein can be utilized for autonomous vehicle navigation, collision avoidance and navigation systems for UAVs, roadway surface texture analysis, non-contact friction analysis, and in-motion deflectometer measurement.