Laser Prism Scanning for Saturation-Free Optical Center Ranging
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Solution Overview
Problem
Laser scanning techniques face challenges in achieving high accuracy due to saturation of light receiving elements by reflective prisms, leading to reduced ranging accuracy.
Innovation Solution
Perform a first laser scan on a reflective prism with known position, followed by a second laser scan with increased scanning density and a widened light amount distribution, using a dimming filter to reduce light intensity and calculate the optical center of the prism based on weighted reflection intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laser scan is performed on a reflective prism with high light intensity, then the signal strength is sufficient for detection, but the light receiving element becomes saturated leading to reduced ranging accuracy
Solution Approach 1:
The patent implements a two-stage scanning process: a first laser scan with normal light intensity to detect the reflective prism's position, followed by a second laser scan with reduced light intensity (achieved by moving the light source closer to the prism or using optical attenuation) to accurately measure the optical center without saturating the light receiving element. This periodic action with varying parameters resolves the contradiction between detection reliability and measurement precision.
Solution Approach 2:
The patent changes the light intensity parameter between two scanning stages. In the first scan, normal light intensity is used for detection. In the second scan, the light intensity is reduced by adjusting the distance between the light source and the reflective prism or by introducing optical attenuation, enabling accurate optical center measurement without saturation while maintaining sufficient signal strength.
2Measurement precision
If the scanning density is increased to improve measurement accuracy, then the precision of optical center determination improves, but the time required for scanning increases
Solution Approach 1:
The patent divides the scanning process into two distinct stages: a first scan that covers a broader area with lower density to locate the reflective prism, and a second scan that focuses specifically on the prism with higher density to accurately determine the optical center. This segmentation allows the system to achieve high precision where needed without unnecessarily increasing overall scanning time.
Solution Approach 2:
The first laser scan serves as a preliminary action to identify the position and presence of the reflective prism. Based on the results of this preliminary scan, the system then performs a targeted second scan with increased density only in the relevant area, avoiding the need to increase density across the entire scanning field and thus minimizing time loss.
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
Improves the accuracy of surveying work by accurately determining the position and posture of the laser scanner, enhancing the precision of point cloud data acquisition.
Implementation Method 1
a second laser scan on the reflective prism in a state where a gradient portion of a light amount distribution of scanning light is widened
Implementation Method 2
performing: a first laser scan on a range including a reflective prism with a known position using a laser scanner
Data Source
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AI summary
The accuracy of surveying work using laser scanning is improved. A laser scanning method including performing: a first laser scan on a range including a reflective prism with a known position using a laser scanner (step S103); detection of the reflective prism based on scan data obtained by the first laser scan (step S106); and a second laser scan on the reflective prism in a state where a gradient portion of a light amount distribution of scanning light is widened compared to a case of the first laser scan (step S105).