Browse Prior Art Database

Moire Pattern Technique for Examining Changes in Materials

IP.com Disclosure Number: IPCOM000094438D
Original Publication Date: 1965-Jan-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Vogel, MJ: AUTHOR [+2]

Abstract

This is a technique for examining changes on the surface of materials. The technique involves superpositioning two micro-images of the same surface and moving those images relative to each other. The relative movement can be a small rotation about a point common to both images or a small translation of the images. The relative movement causes the superpositioned images to exhibit moire-like patterns which are used as indicators of the surface condition.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Moire Pattern Technique for Examining Changes in Materials

This is a technique for examining changes on the surface of materials. The technique involves superpositioning two micro-images of the same surface and moving those images relative to each other. The relative movement can be a small rotation about a point common to both images or a small translation of the images. The relative movement causes the superpositioned images to exhibit moire-like patterns which are used as indicators of the surface condition.

One arrangement is carried out by exposing microphotographs of a surface at various times during a heat treatment process. The first microphotograph negative is superpositioned over the subsequent negatives one at a time. The superpositioned negatives form moire patterns which become increasingly less distinct as the first negative is placed over the negatives exposed after longer and longer heating times. Using this technique, a vernier measurement of the surface change is obtained as a function of the moire pattern intensity change.

Reference: "Moire Patterns", by G. Oster and Y. Nishijima, Scientific American, May 1963, Pages 54-63.

1