Contour-Guided Height Measurement With Maximum Parallax

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Solution Overview

Problem

Conventional height measurement devices face challenges in obtaining sufficient parallax, especially when measuring larger targets, which affects the precision of height measurement.

Innovation Solution

A height measurement device with a camera having a rectangular visual field, a moving device, and a control system that images the target, extracts its contour, sets a circumscribed rectangular area parallel to the camera's field, extends this area outward, determines optimal imaging positions for maximum parallax within the camera's field, and estimates height from the parallax in two-dimensional images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the camera visual field size or target size is increased, then the measurement coverage is improved, but the parallax becomes insufficient and measurement precision deteriorates

Engineering Contradiction:
Improvecamera visual field sizeVSAvoidheight measurement precision
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent transitions from a single-camera static imaging approach to a multi-camera stereoscopic imaging approach, adding a spatial dimension to the measurement system. By placing multiple cameras at different positions and calculating three-dimensional coordinates through triangulation, the system achieves sufficient measurement precision for large targets without requiring excessively large camera visual fields.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If multiple imaging positions are determined for maximum parallax, then measurement precision is improved, but the complexity of positioning and control increases

Engineering Contradiction:
Improveheight measurement precisionVSAvoidpositioning and control complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical positioning systems with a computational approach. Instead of using multiple movable cameras requiring precise mechanical control, the system uses fixed multi-camera arrangements with predetermined positions, achieving maximum parallax through intelligent camera placement and coordinate calculation rather than mechanical movement and adjustment.

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

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 approach ensures precise height measurement of large targets by securing sufficient parallax, enhancing measurement accuracy.

Implementation Method 1

determine multiple imaging positions such that maximum parallax is obtained within a range where the set extension area does not protrude from the visual field of the camera

Methodology Applied
Scientific EffectParallax: Parallax

Data Source

PatentEP4036517B1Height measurement device
Publication Date: 2023.08.23 FUJI CORP

AI summary

A height measurement device images a target loaded at a predetermined position of a loading surface, and extracts a contour of the target from a two-dimensional image of the imaged target. Subsequently, the height measurement device sets a circumscribed rectangular area of which each side is parallel to a corresponding side of the visual field of the camera and each side is circumscribed with the extracted contour of the target, and sets an extension area in which each of four sides of the set circumscribed rectangular area is extended outward by a predetermined amount. Next, the height measurement device determines multiple imaging positions such that maximum parallax is obtained within a range where the extension area does not protrude from the visual field of the camera. Then, the height measurement device images the target at each of the determined multiple imaging positions, and estimates a height of the target from parallax of a two-dimensional image of the target imaged at each of the multiple imaging positions.