Adaptive LIDAR Scanning with Variable Angular Resolution
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Solution Overview
Problem
Current LIDAR systems are limited in their ability to scan objects with target spatial resolution in a timely manner, as they often require scanning over large angular ranges, which can be inefficient and time-consuming.
Innovation Solution
The implementation of adaptive scanning techniques in LIDAR systems, which involve determining a target spatial resolution and adjusting angular resolutions and scan patterns dynamically based on the range and spatial density of objects, allowing for focused scanning within specific angular ranges associated with desired objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LIDAR systems scan over large angular ranges to achieve target spatial resolution, then measurement precision is improved, but loss of time increases due to inefficient and time-consuming scanning
Solution Approach 1:
The patent applies local quality by varying the angular resolution dynamically across different angular ranges. Instead of using uniform high angular resolution across the entire scanning range, the system uses finer angular resolution only in regions where targets are detected or expected, while using coarser resolution in empty or less important regions. This resolves the contradiction by maintaining measurement precision in critical areas while significantly reducing scanning time in non-critical areas.
Solution Approach 2:
The patent implements dynamics by making the angular resolution adjustable and adaptive during the scanning process. The system dynamically changes the angular resolution based on real-time detection of targets, range information, and spatial density. This allows the system to transition from coarse scanning to fine scanning only where necessary, thereby reducing overall scanning time while maintaining required spatial resolution for target detection.
2Measurement precision
If LIDAR systems use high pulse peak power to achieve acceptable range accuracy at long range, then measurement precision is improved, but optical components degrade rapidly
Solution Approach 1:
The patent applies periodic action by using pulsed laser operation with carefully controlled pulse repetition rates. Instead of continuous high-power illumination, the system uses periodic pulses with sufficient intervals to allow optical components to cool and recover. This resolves the contradiction by achieving necessary range accuracy through accumulated pulse measurements while preventing rapid degradation through periodic rest periods for the optical components.
Solution Approach 2:
The patent substitutes mechanical/optical power scaling with signal processing techniques. Instead of relying solely on increasing pulse peak power to improve range accuracy, the system uses coherent detection, phase encoding, and signal integration methods to extract precise range information from lower-power pulses. This resolves the contradiction by achieving measurement precision through enhanced detection and processing rather than brute-force high power, thereby protecting optical components.
3Productivity
If LIDAR systems use coarse angular resolution to reduce scanning time, then loss of time is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent applies local quality by implementing variable angular resolution that adapts to local scene characteristics. The system performs initial coarse scanning to identify regions with targets or high spatial density, then applies finer angular resolution only to those specific regions. This resolves the contradiction by maintaining high scanning speed overall while achieving necessary measurement precision locally where targets are present.
Solution Approach 2:
The patent implements preliminary action by performing a first pass of coarse scanning to gather preliminary range and target location information before conducting detailed fine scanning. This preliminary coarse scan allows the system to identify which regions require high-resolution measurement, thereby avoiding unnecessary fine scanning in empty regions and maintaining overall productivity while ensuring measurement precision where needed.
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 faster acquisition of range data with improved spatial resolution, concentrating scanning efforts on areas of interest while reducing unnecessary measurements, thereby enhancing the efficiency and speed of data collection.
Implementation Method 1
using the same modulated optical carrier as a reference signal that is combined with the returned signal at an optical detector to produce in the resulting electrical signal a relatively low beat frequency that is proportional to the difference in frequencies or phases between the references and returned optical signals. This kind of beat frequency detection of frequency differences at a detector is called heterodyne detection.
Implementation Method 2
uses, as the reference optical signal, an optical signal split from the transmitted optical signal. This arrangement is called homodyne detection in that patent.
Implementation Method 3
direct ranging based on round trip travel time of an optical pulse to an object
Data Source
AI summary
Techniques for automatic adaptive scanning with a laser scanner include obtaining range measurements at a coarse angular resolution and forming a horizontally sorted range gate subset and a characteristic range. A fine angular resolution is determined automatically based on the characteristic range and a target spatial resolution. If the fine angular resolution is finer than the coarse angular resolution, then a minimum and maximum vertical angle is automatically determined in each horizontal slice extending a bin size from any previous horizontal slice. A set of adaptive minimum and maximum vertical angles is determined automatically by dilating and interpolating the minimum and maximum vertical angles of all the slices to the second horizontal angular resolution. A horizontal start angle, and the set of adaptive minimum and maximum vertical angles are sent to cause the ranging system to obtain measurements at the second angular resolution.