Browse Prior Art Database

Concentric Part Inspection Device

IP.com Disclosure Number: IPCOM000045949D
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Grossman, DD: AUTHOR [+2]

Abstract

An apparatus and method for measuring concentricity of parts using machine vision techniques are described. The apparatus includes a back-lighted table and an imaging device. A region analysis algorithm is used by a computer to process the output data from the imaging device to determine the degree of eccentricity.

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Concentric Part Inspection Device

An apparatus and method for measuring concentricity of parts using machine vision techniques are described. The apparatus includes a back-lighted table and an imaging device. A region analysis algorithm is used by a computer to process the output data from the imaging device to determine the degree of eccentricity.

Problem

Flat mechanical parts, such as the one shown in Fig. 1, are often produced in which the "outer shape" (labeled "A") is first stamped and then the "inner shape" ("B") is then stamped. If the part is not correctly aligned in step 2, an eccentric part may result (Fig. 2). This publication describes an automatic, computer- based, non-contact measurement scheme for determining the degree of eccentricity of nominally concentric parts.

Method

Fig. 3 shows the apparatus for measuring concentricity. The part "P" is placed on a back-lighted table "T" in the field of view of an imaging device "I" connected to a computer "C". "I" produces a binary image, i.e., an array of bits in which 0 indicates a black point (corresponding to material in "P") and 1 indicates a bright point (corresponding to the background and the hole in "P"). Using a region analysis algorithm (*), it is possible to determine the center-of- gravity position for the material of the part and for the enclosed hole (points "X" and "O", Fig. 4).

The degree of eccentricity is given by the distance d between points "X" and "0" (Fig. 4), suitably weighted by di...