Optical Distance Measuring Device Pseudo Object Removal
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Solution Overview
Problem
Existing optical distance measuring devices face challenges in accurately detecting targets due to the detection of pseudo objects caused by doubly reflected laser light, leading to inaccurate distance measurements and potential collision avoidance issues.
Innovation Solution
The optical distance measuring device employs a controller with a light emitting unit, scanning unit, and light receiving unit to emit and receive laser light, and uses a pseudo object determination unit to identify and remove pseudo objects by analyzing peak signals and determining their distance based on the number of reflections, thereby distinguishing between actual and pseudo objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical distance measuring device emits laser light to detect targets, then the detection range and coverage are improved, but pseudo objects are detected due to doubly reflected laser light, leading to inaccurate distance measurements
Solution Approach 1:
The patent applies preliminary action by calculating expected pseudo object positions based on the formula L2 = N × L1 (where L1 is the distance to the first object, L2 is the distance to the pseudo object, and N is a natural number of 2 or more) before detection occurs. The controller proactively identifies and removes pseudo object detection results by comparing detected object positions with calculated pseudo object positions, preventing inaccurate measurements from affecting the system's reliability.
2Measurement precision
If the device detects all reflected light signals, then the detection sensitivity is improved, but the window reflection is detected as a target, causing false detection results
Solution Approach 1:
The patent applies the taking out principle by specifically extracting and removing the window reflection signal from the detected light signals. The controller identifies the window as the light source of emitted light and removes detection results corresponding to light reflected by the window, separating the harmful window reflection signal from useful target detection signals while maintaining detection sensitivity for actual targets.
3Measurement precision
If the controller processes all detection signals, then the detection completeness is improved, but the processing time and computational load increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating the positions where pseudo objects would appear using the formula L2 = N × L1 before processing detection signals. The controller uses these pre-calculated positions to quickly identify and remove pseudo object detection results, reducing the computational load and processing time compared to analyzing all detection signals without prior preparation.
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 solution effectively reduces the influence of pseudo objects on distance measurements, allowing for accurate target detection and preventing unnecessary collision avoidance controls, enhancing the reliability of the device.
Implementation Method 1
a light emitting unit that emits emitted light
Implementation Method 2
reflected light, which corresponds to the emitted light reflected by an object
Implementation Method 3
a light receiving unit that has a light receiving pixel for receiving incident light and outputs a detection signal corresponding to received light intensity
Data Source
AI summary
An optical distance measuring device includes a light-emitting unit emitting light, a light-receiving unit having a light-receiving pixel for receiving incident light and outputting a detection-signal corresponding to received-light intensity of the incident light, and a controller acquiring a detection-signal corresponding to received-light intensity of reflected light, which corresponds to the emitted light reflected by an object, from the light-receiving unit that has received the reflected light as the incident light, to detect a distance to the object by using the detection-signal corresponding to the received-light intensity. When a first object and a second object at distance which is N times a distance to the first object on an extension of a straight line connecting the measuring device and the first object are detected, and the second object is determined to be a pseudo object corresponding to the first object, the controller removes a detection result of the second object.