LIDAR Retroreflector Mapping with Low-Intensity Pulse Prechecks
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Solution Overview
Problem
LIDAR systems face errors and inaccuracies due to reflections from retroreflectors and highly reflective surfaces, leading to issues like retroreflector aliasing, channel cross-talk, and blooming, which affect data collection and interpretation.
Innovation Solution
A LIDAR device employs a primary emitter for high-intensity light pulses and a secondary emitter for lower-intensity pulses to illuminate the scene, using the secondary pulses to detect retroreflectors and control the primary emitter to avoid illuminating them, thereby preventing scanning errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-intensity light pulses are used to illuminate the scene, then the illumination intensity and detection capability are improved, but retroreflector aliasing, channel cross-talk, and blooming errors increase
Solution Approach 1:
The system transmits a preliminary low-intensity light pulse before the high-intensity pulse to detect retroreflectors in advance. By detecting the return signal from the preliminary pulse, the system can identify retroreflectors before the main measurement and avoid illuminating them with high-intensity light, thereby preventing aliasing and blooming errors while maintaining overall measurement accuracy
Solution Approach 2:
The system uses the harmful retroreflector return signals from low-intensity pulses as useful information to identify retroreflector locations. These previously problematic reflections are converted into detection cues that enable the system to avoid high-intensity illumination of retroreflectors in subsequent measurements, transforming the error source into a beneficial detection mechanism
2Measurement precision
If multiple light pulses are transmitted sequentially, then retroreflector detection capability is improved, but the time required for scanning increases
Solution Approach 1:
The system uses periodic alternating transmission of low-intensity and high-intensity light pulses. The low-intensity pulse is transmitted first for retroreflector detection, followed by the high-intensity pulse for normal measurement. This periodic pattern allows efficient retroreflector identification without requiring excessive time, as the preliminary detection occurs at minimal intervals between normal measurements
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 effectively reduces errors associated with retroreflectors by pre-empting or delaying high-intensity light pulses, improving data accuracy and reducing false reflections.
Implementation Method 1
transmitting a plurality of light pulses toward the scene... detecting reflections of the emitted signals
Implementation Method 2
determining a distance to the object according to a time delay between the transmission of the pulse and the reception of the reflected pulse
Implementation Method 3
focusing, by a light detection and ranging (LIDAR) device, light from a target region in a scene for receipt by a detector
Data Source
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AI summary
One example method involves a light detection and ranging (LIDAR) device focusing light from a target region in a scene for receipt by a detector. The method also involves emitting a primary light pulse. The method also involves directing, via one or more optical elements, the primary light pulse toward the target region. The primary light pulse illuminates the target region according to a primary light intensity of the primary light pulse. The method also involves emitting a secondary light pulse. At least a portion of the secondary light pulse illuminates the target region according to a secondary light intensity of the secondary light pulse. The secondary light intensity is less than the primary light intensity.