LiDAR Defocusing Detection Using Segmented Matrix Detector
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Solution Overview
Problem
LiDAR sensors in the automotive sector face functional disruptions due to contamination on protective glass and adverse weather conditions, leading to defocusing issues that affect distance measurement accuracy.
Innovation Solution
A method utilizing a matrix-shaped detector unit with separate first and second receiving areas, where the first area is calibrated for distance measurement and the second area is activated intermittently to detect defocusing by analyzing secondary light, allowing for the determination of defocusing extent and triggering cleaning or alternative sensor use when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective glass is added to protect the LiDAR sensor from environmental influences, then the sensor's protection against dirt and weather is improved, but defocusing occurs due to contamination on the glass surface
Solution Approach 1:
The detector unit is divided into a first receiving area for distance measurement and a second receiving area for defocusing detection. This segmentation allows the system to simultaneously maintain protection through the glass while detecting and compensating for defocusing effects caused by contamination on the glass surface.
Solution Approach 2:
The system uses the second receiving area to detect defocusing conditions and provides feedback about the extent of defocusing. This feedback enables the system to identify when contamination on the protective glass is affecting measurement accuracy, allowing for appropriate responses such as triggering cleaning mechanisms or flagging measurement data as unreliable.
2Reliability
If cleaning devices are added to remove contamination from the protective glass, then the functional restriction is eliminated, but the device complexity increases
Solution Approach 1:
The LiDAR sensor system performs self-diagnosis by using its own detector unit to detect defocusing caused by glass contamination. The system autonomously identifies when cleaning is needed without requiring external monitoring systems, enabling self-service operation while maintaining reliability.
Solution Approach 2:
The detector unit serves multiple functions: it performs both distance measurement (first receiving area) and defocusing detection (second receiving area). This multi-functionality eliminates the need for separate dedicated defocusing detection systems, reducing overall device complexity while maintaining the ability to trigger cleaning operations when needed.
3Measurement precision
If the second receiving area is activated during individual scans of multiple consecutive scans, then defocusing detection is achieved, but the scanning time and productivity are affected
Solution Approach 1:
The second receiving area is activated periodically during individual scans of multiple consecutive scans rather than continuously. This periodic activation allows defocusing detection to occur at regular intervals, maintaining measurement precision while minimizing the impact on overall scanning productivity by keeping the system operational during non-detection periods.
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 precise detection and mitigation of defocusing without additional systems, ensuring reliable distance measurements and maintaining vehicle safety by activating cleaning devices or switching to alternative sensors when defocusing exceeds thresholds.
Implementation Method 1
emitting primary light in the form of a laser line into a field of view of the LiDAR sensor by means of at least one laser emitter unit
Implementation Method 2
receiving secondary light reflected and/or scattered in the field of view by an object
Implementation Method 3
receiving secondary light reflected and/or scattered in the field of view by an object
Implementation Method 4
A distance between a LiDAR sensor and an object in a field of view of the LiDAR sensor can be determined by means of the LiDAR sensor, for example based on a signal propagation time (time of flight TOF)
Data Source
AI summary
A method for detecting defocusing of a LiDAR sensor. The method includes: emitting primary light as a laser line into a field of view of the LiDAR sensor to scan the field of view; receiving secondary light reflected and/or scattered in the field of view by an object using a matrix-shaped detector unit, the detector unit including a first receiving area and a second receiving area which differs from the first receiving area; determining a distance between the LiDAR sensor and an object based on secondary light received in the first receiving area; and ascertaining information about an extent of defocusing based on secondary light received in the second receiving area. The first receiving area is determined by calibrating the matrix-shaped detector unit. The first receiving area and the second receiving area are activated separately from one another to receive secondary light.