Hose Appearance Inspection Using Slit Light Height Data Subtraction
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Solution Overview
Problem
The existing methods for inspecting the appearance of long-length objects with a spirally wrapped cloth member face challenges in accurately detecting unevenness and defects due to the rough surface texture and overlapping recessed/convex portions, as well as interference from product markings, making it difficult to distinguish unusual levels of unevenness.
Innovation Solution
A method involving the irradiation of slit light onto the object's surface, moving the light source and object relative to each other, and taking images of the lighted line from an angled direction to extract height position data, subtracting base data corresponding to the object's shape, and arranging the data into an inspection image based on a color standard for accurate judgment of unusual features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional appearance inspection method is used on hose with spirally wrapped cloth member, then inspection process is simple, but measurement precision deteriorates due to rough surface texture and spiral recessed/convex portions
Solution Approach 1:
The patent transitions from 2D surface imaging to 3D contour measurement by projecting light and detecting height position data. The light projection device projects light onto the object surface, and the imaging device captures the lighted line from which height position data is extracted, creating a three-dimensional representation that distinguishes actual defects from surface texture variations.
Solution Approach 2:
The patent replaces manual tactile inspection with an optical measurement system. Instead of relying on inspector skill and physical contact, the system uses light projection and image capture to automatically detect and measure surface irregularities, eliminating subjectivity and physical interference from the inspection process.
2Productivity
If conventional appearance inspection method is used, then inspection speed is fast, but measurement precision deteriorates due to interference from product markings and spiral texture
Solution Approach 1:
By measuring the height position data of the lighted line and creating 3D contour information, the system can distinguish between superficial markings (zero or minimal height variation) and actual defects (significant height deviations). This dimensional addition allows rapid automated inspection without sacrificing precision.
3Adaptability or versatility
If manual inspection by inspector is used, then flexibility in judgment is improved, but measurement precision deteriorates due to variation in inspector skill level
Solution Approach 1:
The patent replaces human inspectors with an automated optical measurement system that consistently applies the same measurement criteria. The system extracts height position data and compares it against predetermined standards, eliminating variability due to inspector skill while maintaining objective judgment through programmable acceptance criteria.
4Measurement precision
If slit light projection and height position data extraction method is used, then measurement precision is improved for detecting unusual unevenness, but device complexity increases
Solution Approach 1:
The imaging device serves multiple functions: it captures images for visual inspection, extracts height position data for 3D contour measurement, and provides the lighted line information needed for both qualitative and quantitative analysis. This multi-functionality reduces the need for separate specialized devices.
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 allows for continuous and accurate imaging of the object's contour, clearly clarifying unevenness, defects, and other features on the inspection image, enabling precise appearance inspection of long-length objects with spirally wrapped surfaces.
Implementation Method 1
reflection of light in a portion of the unevenness or defect is characteristic
Data Source
AI summary
An apparatus for inspecting appearance of long-length object takes images of lighted line every predetermined timing while making the hose move in the long-length direction. By this, the contours of the hose are taken continuously and correctly over the length direction of the hose. The height direction position data of the lighted line corresponding to each of the width direction position of the hose are extracted, and the height direction position data are subtracted by the base data provided so as to correspond to each of the width direction position. Thus, the arc shape of the outer surface of the hose is canceled from the height direction position data. Also, the height direction position data of each taken image which are given the subtracting is put in image-taking order, and an inspection image is made on the basis of the predetermined color.