LIDAR Optical Crosstalk Mitigation via Segmented Pixel Grouping
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Solution Overview
Problem
LIDAR systems face optical crosstalk issues due to highly reflective objects, leading to glare artefacts that block essential parts of the scene, resulting in inaccuracies and potential safety issues in autonomous driving applications.
Innovation Solution
A LIDAR system with a transmitter that projects light beams with an oblong shape perpendicular to the scanning direction and a receiver with a photodetector array and optical crosstalk detection circuit, which selectively illuminates targeted regions and detects optical crosstalk by processing electrical signals from targeted and non-targeted pixel groups to define a glare artefact box.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a one-dimensional scanner is used in LIDAR, then the device complexity is reduced, but optical crosstalk occurs due to glare and scattering from highly reflective targets
Solution Approach 1:
The patent segments the photodetector array into multiple independently controllable pixel groups, each corresponding to a specific region in the field of view. This allows selective illumination and detection strategies to be applied to different regions, mitigating optical crosstalk from highly reflective targets in specific areas while maintaining normal operation in other areas.
Solution Approach 2:
The patent implements periodic illumination by alternating between illuminating targeted pixel groups and non-targeted pixel groups over time. This temporal separation allows the system to detect optical crosstalk artifacts by comparing signals from different illumination phases, enabling artifact identification and mitigation while using a simple one-dimensional scanner.
2Measurement precision
If selective illumination of targeted regions is implemented, then measurement precision in specific areas is improved, but the device complexity increases due to coordinated control of light sources and photodetectors
Solution Approach 1:
The patent divides both the light source array and photodetector array into corresponding pixel groups, where each group is associated with a specific region in the field of view. This segmentation enables independent control and processing of signals from different regions, improving measurement precision in targeted areas while managing complexity through modular organization.
Solution Approach 2:
The patent employs feedback mechanisms where the controller receives signals from the photodetector array and adjusts illumination patterns accordingly. By monitoring detection signals and coordinating illumination based on detected optical crosstalk artifacts, the system optimizes measurement precision while adapting to varying scene conditions.
3Measurement precision
If optical crosstalk detection is performed by processing signals from both targeted and non-targeted pixel groups, then artifact detection accuracy is improved, but processing time and computational load increase
Solution Approach 1:
The patent uses periodic illumination patterns where targeted and non-targeted pixel groups are illuminated alternately in distinct time phases. This temporal structuring allows the system to process signals in an organized manner, comparing corresponding pixel groups from different phases to identify optical crosstalk artifacts efficiently, balancing detection accuracy with processing time.
Solution Approach 2:
The patent performs preliminary organization of pixel groups into targeted and non-targeted categories before signal processing. By pre-defining which pixel groups correspond to illuminated regions and which correspond to non-illuminated regions, the system streamlines the artifact detection process, reducing computational complexity and processing time while maintaining 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
Effectively mitigates optical crosstalk, enhancing the accuracy of depth measurements and reducing safety risks by identifying and isolating glare artefacts, thereby improving the reliability of LIDAR imaging.
Implementation Method 1
a photodetector array configured to receive at least one reflected light beam and generate electrical signals based on the at least one reflected light beam
Data Source
AI summary
A method of detecting optical crosstalk in a LIDAR system includes selectively activating and deactivating light sources of a light source array; triggering a measurement of the field of view (FOV) during which at least one targeted region of the FOV is illuminated by the light source array and at least one non-targeted region of the FOV is not illuminated by the light source array; generating electrical signals based on at least one reflected light beam being received by a photodetector array, where the photodetector array comprises a targeted pixel group corresponding to the at least one targeted region of the FOV and a non-targeted pixel group corresponding to the at least one non-targeted region of the FOV; and detecting optical crosstalk that appears at at least one portion of the non-targeted pixel group based on electrical signals from the targeted pixel group and the non-targeted pixel group.