Lidar Sensor Blockage Detection via Selective Light Source Deactivation
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Solution Overview
Problem
Lidar sensors experience performance degradation due to blockages such as water, snow, and dirt on their transparent covers, leading to reduced detection distance, image quality, and false returns, necessitating effective blockage detection and cleaning mechanisms.
Innovation Solution
A lidar sensor assembly with multiple light sources and photodetectors, where a processor determines blockages by analyzing signals from photodetectors, including selectively ceasing operation of light sources to detect changes in signal patterns indicative of blockages, and calculates time of flight to confirm blockage presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the lidar sensor operates in normal mode with all light sources active, then detection range and image quality are maintained, but the sensor cannot detect blockages on the transparent cover
Solution Approach 1:
The system periodically alternates between normal operation mode and blockage detection mode. During blockage detection mode, selected light sources are selectively deactivated in a periodic sequence, allowing the photodetectors to capture reference signals without interference from direct light source emissions. This periodic switching enables blockage detection while maintaining overall sensor functionality.
Solution Approach 2:
The invention extracts the blockage detection function as a separate operational mode from the normal sensing function. By selectively turning off specific light sources during detection phases, the system isolates the blockage detection task from regular operation, allowing independent optimization of detection accuracy without compromising normal sensing performance.
2Measurement precision
If light sources are continuously operated to maintain detection range, then maximum detectable distance is preserved, but blockages create false returns and halo effects that degrade image quality
Solution Approach 1:
The system dynamically adjusts light source operation based on the detected phase. During normal operation, all light sources remain active to maximize detection range. During blockage detection phases, specific light sources are dynamically deactivated to eliminate false returns and halo effects, thereby improving image quality without permanently sacrificing detection capability.
3Reliability
If the sensor transitions to low-performance mode to notify drivers of persistent blockages, then driver safety is ensured, but detection capability and productivity are reduced
Solution Approach 1:
The system performs preliminary blockage detection by selectively deactivating light sources and analyzing photodetector signals before blockages severely impact normal operation. This preliminary detection allows the system to notify drivers of potential issues before they compromise safety or detection capability, enabling preventive maintenance rather than reactive response.
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
Enables real-time detection and mitigation of blockages, maintaining sensor performance by activating cleaning mechanisms and transitioning to low-performance mode if blockages persist, ensuring accurate object detection and driver notification.
Implementation Method 1
a plurality of light sources configured to generate light for illuminating a field of view
Implementation Method 2
a plurality of photodetectors for detecting the light potentially reflected off of objects in the field of view
Implementation Method 3
calculates time of flight to confirm blockage presence
Data Source
AI summary
A lidar sensor assembly includes a plurality of light sources configured to generate light and a plurality of photodetectors for detecting the light potentially reflected off of objects in a field of view. Each of the photodetectors is associated with and configured to receive the light generated by one of the plurality of light sources. A generally transparent cover is disposed between (a) at least one of plurality of light sources and the plurality of photodetectors and (b) the field of view. The assembly further includes a processor in communication with the plurality of light sources and the plurality of photodetectors. The processor is configured to receive signals from the plurality of photodetectors. The processor is further configured to determine whether a blockage of the generally transparent cover exists based at least partially on the signals from the plurality of photodetectors.