Laser Area Sensor Weather Correction
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Solution Overview
Problem
Laser area sensors face challenges in accurately detecting intruders during bad weather conditions such as rain, snow, and dense fog due to light reflection and attenuation, leading to potential erroneous detection.
Innovation Solution
A laser area sensor system that includes a first laser range finder, a scanning mechanism, an information acquiring portion, and a human body judging portion, which corrects distance and light-reception level information to remove discontinuous changes and attenuated data, allowing for accurate detection of human bodies by identifying gentle curves protruding downward within a certain width based on time-series moving status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser light is used for detection in outdoor environments, then detection capability is improved, but reliability deteriorates during bad weather conditions (rain, snow, dense fog) due to light reflection and attenuation
Solution Approach 1:
The system performs preliminary actions by measuring distance information and light-reception level information before making detection judgments. The information acquiring portion continuously collects data in advance, and the information correcting portion processes this pre-collected data to remove discontinuous changes and correct attenuation effects, enabling reliable detection even during bad weather conditions
Solution Approach 2:
The system implements feedback mechanisms where the light-reception level information is used to correct and adjust the distance information. The information correcting portion uses the feedback from light-reception levels to identify and remove erroneous distance measurements caused by weather conditions, thereby maintaining detection reliability
2Adaptability or versatility
If distance information is obtained during bad weather, then detection coverage is maintained, but measurement precision deteriorates due to discontinuous changes and attenuation
Solution Approach 1:
The system acquires distance information and light-reception level information in advance during the measurement period, before final detection decisions are made. This preliminary data collection allows the information correcting portion to process and clean the data, removing discontinuous changes while maintaining detection coverage
Solution Approach 2:
The information correcting portion acts as an intermediary between the raw distance measurements and the final detection results. It processes the distance information by removing discontinuous changes and correcting attenuation effects, thereby improving measurement precision while preserving detection coverage
3Area of stationary object
If laser light passes through rain, snow, or dense fog, then detection area is maintained, but light is reflected or attenuated, causing erroneous detection
Solution Approach 1:
The system performs preliminary measurement of distance information and light-reception level information before making detection judgments. This allows the information correcting portion to identify and remove erroneous data points caused by weather conditions, maintaining both detection area and accuracy
Solution Approach 2:
The system converts the harmful effects of weather conditions (light reflection and attenuation) into beneficial information by measuring light-reception level data. This measured information is then used to correct and identify erroneous distance measurements, transforming the weather interference from a purely harmful factor into a detectable and correctable signal
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 accurate detection of intruders even in rainy, snowy, and foggy conditions while minimizing erroneous detection, ensuring reliable security systems.
Implementation Method 1
a first laser range finder that emits pulsed laser light, measures a period of time for light reflected by at least one object that is present in a laser light emitting direction to return thereby to obtain distance information to the object
Implementation Method 2
measures a period of time for light reflected by at least one object that is present in a laser light emitting direction to return
Implementation Method 3
a scanning mechanism portion that changes a measurement direction of the first laser range finder
Implementation Method 4
acquires distance information and light-reception level information in each measurement direction in the detection area in a time-series manner, by the first laser range finder periodically performing measurement
Implementation Method 5
removes distance information corresponding to the discontinuous change in the measurement period in the measurement direction and corrects light-reception level information of a portion that does not correspond to the discontinuous change
Implementation Method 6
extracts a portion that is presumed to correspond to a human body, from the distance information corrected by the first information correcting portion, and judges whether or not the extracted portion matches a gentle curve protruding downward with a certain width
Data Source
Figure 1~2
Figure 3
Figure 4(a)~4(d)
AI summary
A laser area sensor according to an embodiment includes: a laser range finder (110) that obtains a distance to an object and a light-reception level of reflected light: a scanning mechanism (120) that changes the measurement direction; a data acquiring portion (130) that periodically performs measurement while changing the measurement direction; a data correcting portion (135) that removes distance information of a portion corresponding to a discontinuous change and corrects light-reception level information of a portion that does not correspond to the discontinuous change after the obtained distance information and light-reception level information are compared with distance information and light-reception level information of preceding and succeeding measurement periods in each direction; a human body judging portion (140) that extracts a portion that is presumed to correspond to a human body, from the corrected distance information, and judges whether or not the extracted portion matches a human body based on a time-series moving status of the extracted portion; and an alert output control portion (150) that outputs a human body detection signal.