Browse Prior Art Database

Non-Contact Butt-Weld Inspection Device

IP.com Disclosure Number: IPCOM000042859D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 3 page(s) / 54K

Publishing Venue

IBM

Related People

Lavin, MA: AUTHOR

Abstract

A device and method for measuring the degree of planar misalignment between flat plates joined by butt welding are described. The device employs two slit projectors, an imaging device and a computer for processing the image data using a region analysis algorithm. Introduction Reference 1 describes the problem of checking the alignment in butt-welded objects, and a device employing contact sensors to perform such checking. This publication describes a non-contact device which employs machine vision techniques. Apparatus Fig. 1 illustrates the structure of the butt-weld inspection device. It consists of the following principal components: 1) A WORK SURFACE to support the plate being inspected. 2) Two SLIT PROJECTORS producing collimated planes of light which falling on the plate, produce two stripes. 3) An IMAGE SENSOR, e.g.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Non-Contact Butt-Weld Inspection Device

A device and method for measuring the degree of planar misalignment between flat plates joined by butt welding are described. The device employs two slit projectors, an imaging device and a computer for processing the image data using a region analysis algorithm. Introduction Reference 1 describes the problem of checking the alignment in butt-welded objects, and a device employing contact sensors to perform such checking. This publication describes a non-contact device which employs machine vision techniques. Apparatus Fig. 1 illustrates the structure of the butt-weld inspection device. It consists of the following principal components: 1) A WORK SURFACE to support the plate being inspected. 2) Two SLIT PROJECTORS producing collimated planes of light which falling on the plate, produce two stripes. 3) An IMAGE SENSOR, e.g., vidicon or solid-state array. 4) An INTERFACE to convert sensor data into a BINARY IMAGE (each picture element (pixel) described by a single bit). 5) A COMPUTER to perform analysis described below. Method The apparatus above allows checking for the alignment of the planar surfaces on the two sides of the butt-weld as follows. The apparatus produces a binary image like the one in Fig. 2, in which 1-bits correspond to points in stripe 1 or stripe 2. The image is masked to two rectangular windows W1 and W2, as shown in Fig. 2; masking is performed by performing a pixel-by-pixel logical AND operation between the original images and a mask image containing l-bits in areas W1 and W2, and 0 bits elsewhere. The result of the masking process is that stripes W1 and W2 are transformed into four disjoint regions R1, R2, R3 and R4. By using a region analysis algorithm [2] it is possible to determine the center (X1,Y) coordinates and angular orientation of each region. The essential point of the inspection method is that if the surfaces on either side of the weld are coplanar, region R1 will be colinear with R4 and R3 with R2. Inspection can proceed in one of...