Three-Camera Overhead Line Measurement Device

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Solution Overview

Problem

Existing line measurement devices face challenges in achieving both a wide imaging range and fine imaging resolution for overhead lines, particularly the crossing line, due to limitations in camera placement and the use of laser range meters, which are not suitable for high-speed commercial vehicles.

Innovation Solution

A line measurement device employing three line-sensor cameras placed at opposite ends and the center of a vehicle, with one camera having a wider imaging range to cover the crossing line's deviation of ±900 mm, and utilizing pantograph height information to differentiate the crossing line from other overhead lines, eliminating the need for laser range meters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the camera-to-camera distance is made long to improve imaging resolution, then the height resolution is improved, but the imaging range cannot cover the crossing line

Engineering Contradiction:
Improveheight resolutionVSAvoidimaging range
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent divides the imaging task into multiple segments by using three cameras positioned at different locations (two at opposite ends, one at center). Each camera captures a specific portion of the overhead line, with the center camera providing wide-angle coverage for crossing lines and end cameras providing high-resolution stereo measurement for main lines. This segmentation allows the system to achieve both wide imaging range and fine measurement precision simultaneously.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the camera-to-camera distance is made short to expand imaging range, then the imaging range can cover the crossing line, but the height resolution deteriorates

Engineering Contradiction:
Improveimaging rangeVSAvoidheight resolution
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies different quality requirements to different spatial locations. The center camera is positioned to provide wide imaging range for crossing lines, while the end cameras are positioned to provide high-resolution stereo measurement for main lines. This local differentiation of imaging quality allows the system to optimize for different measurement needs in different regions without compromising overall performance.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If laser range meters are used to match stereo-corresponding points, then the matching accuracy is improved, but the device is not suitable for high-speed commercial vehicles

Engineering Contradiction:
Improvematching accuracyVSAvoidvehicle speed compatibility
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent replaces the mechanical laser range meter system with an optical image processing system. Instead of using laser beams to measure distances and match points, the system uses image data from multiple cameras and applies stereo vision algorithms to identify corresponding points and calculate positions. This substitution eliminates the speed limitations of laser range meters while maintaining or improving measurement accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Area of stationary object

If three cameras are used with one having wider imaging range, then both wide imaging range and fine imaging resolution are achieved, but the device complexity increases

Engineering Contradiction:
Improveimaging rangeVSAvoidcamera configuration
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent designs the camera system to perform multiple functions: the center camera with wide imaging range handles crossing line detection, while all three cameras work together for main line measurement. This multi-functionality allows the system to measure both crossing lines and main lines accurately, reducing the need for separate specialized devices and justifying the increased complexity through enhanced versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration allows for high-resolution stereo measurement with a wide imaging range covering the crossing line, improving detection accuracy and suitability for high-speed commercial vehicles by leveraging the characteristic height difference between the crossing and main lines.

Implementation Method 1

three line-sensor cameras 1, 2, and 3 placed at opposite ends and a center of a top of a vehicle... images of overhead lines captured by the three line-sensor cameras

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

The stereo measurement is a technique that calculates three-dimensional position information based on information on the parallax between a plurality of cameras

Methodology Applied
Scientific EffectParallax: Parallax

Data Source

PatentEP3199910B1Line measurement device and method
Publication Date: 2020.06.24 MEIDENSHA CORP
  • EP3199910B1 patent drawingFigure 1~2
  • EP3199910B1 patent drawingFigure 3~4
  • EP3199910B1 patent drawingFigure 5~6

AI summary

A line measurement device that has three line-sensor cameras (1, 2, 3) for imaging overhead lines (8, 9) disposed on both sides and in the center of a vehicle (10) and measures the heights and deviations of the overhead lines (8, 9) through image processing using an image processing device (100) that uses stereo measurement of the images of the overhead lines (8, 9) imaged by the three line-sensor cameras (1, 2, 3), said line measurement device being characterized in that the line sensor camera (3) disposed in the center of the vehicle (10) has, as the imaging range thereof, the entirety of a range (E) in which a crossing line (9) is present as an overhead line and the line sensor cameras (1, 2) disposed on both sides of the vehicle (10) each have, as the imaging range thereof, a range of one half of the crossing line range (E) halved by a center line (C) of the vehicle (10).