Angle-Dependent Threshold Function for Vehicle Laser Scanner
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Solution Overview
Problem
Laser scanners for vehicles face challenges in maintaining sensitivity in close-range detection while avoiding false echoes from atmospheric disturbances like rain, fog, and dirt, which are misinterpreted as real targets due to constant detection thresholds that compromise long-range sensitivity.
Innovation Solution
Implementing an angle-dependent detection threshold function that varies with scanning angles, allowing for higher sensitivity in close-range detection and effectively masking out false echoes by adjusting threshold values based on the receiver's sensitivity profile, which changes across the scanning angle range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant detection threshold is used for all scanning angles, then long-range sensitivity is maintained, but false echoes from atmospheric disturbances in close-range are not suppressed
Solution Approach 1:
The patent applies local quality by implementing angle-dependent detection thresholds tailored to specific scanning angle ranges. Different threshold values are assigned to different angular regions: higher thresholds for close-range angles (0°-30°) to suppress false echoes from atmospheric disturbances, and lower thresholds for long-range angles to maintain sensitivity. This localized threshold adjustment resolves the contradiction by optimizing detection parameters for each specific angular zone rather than using a uniform threshold across all angles.
Solution Approach 2:
The patent implements dynamics by making the detection threshold variable rather than static. The threshold dynamically adapts based on the scanning angle, automatically adjusting between high and low values as the transmitter scans through different angular ranges. This dynamic threshold function enables the system to respond appropriately to different detection scenarios (close-range vs. long-range) without manual intervention, resolving the contradiction between suppressing false echoes and maintaining sensitivity.
2Object-affected harmful factors
If the detection threshold is increased to suppress false echoes, then false positives from atmospheric disturbances are reduced, but sensitivity for weakly reflecting targets at great distances is compromised
Solution Approach 1:
The patent applies local quality by assigning different threshold levels to different angular regions. High thresholds are applied only to close-range scanning angles (0°-30°) where atmospheric disturbances create false echoes, while low thresholds are applied to long-range angles where weakly reflecting targets need to be detected. This localized approach ensures that increasing the threshold to suppress false echoes does not compromise the detection of distant targets.
3Reliability
If the detection threshold is decreased to improve close-range sensitivity, then real target objects in close-range are detected better, but false echoes from atmospheric disturbances increase
Solution Approach 1:
The patent applies local quality by implementing angle-specific threshold optimization. For close-range scanning angles (0°-30°) where atmospheric disturbances are problematic, higher thresholds are used to suppress false echoes while still detecting real targets. For other angles where atmospheric interference is less severe, lower thresholds enable better detection sensitivity. This localized threshold strategy resolves the contradiction by optimizing detection parameters for each angular region's specific characteristics.
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
Enhances the ability to detect real target objects in close-range while reducing false positives from atmospheric disturbances, maintaining sensitivity for weakly reflecting targets at great distances without increasing the detection threshold excessively.
Implementation Method 1
Laser scanners operate on the time-of-flight principle and typically include an optical transmitter that emits short laser pulses. The time between the emission of the laser pulse and the reception of the echo is proportional to the distance to the object.
Implementation Method 2
an optical receiver for receiving beams reflected in the area surrounding the vehicle and for providing an electrical signal depending on the received beams
Data Source
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Figure 6
AI summary
The invention relates to a scanning optoelectronic detection device (7), in particular a laser scanner, for a motor vehicle, comprising an optical emitter for emitting electromagnetic beams, an optical receiver (10) for capturing beams (9) reflected on to a target object in the surrounding area of the vehicle and for providing an electric capturing signal (19) in accordance with the captured beams (9), also comprising an evaluation device (25) for detecting the target object in accordance with the electric capturing signal (19). The emitter is designed to respectively transmit an emission beam for a plurality of different scanning angles within a total scanning angle range. The evaluation device (25) is designed to compare, for each scanning angle, the capturing signal (19) with a detection threshold and to detect the target object in accordance with the comparison. Said detection threshold is an angle-dependent threshold value function which comprises threshold values for the capturing signal (19) which are different from each other, for at least two different scanning angles of the emitter.