Determination of the Autocorrelation Function of Woven Fabrics Using Laser Speckle

When a rough surface is irradiated by a laser light and reflected or transmitted light is observed, a diffraction fringe with speckle is obtained at the observation plane. This diffraction fringe is called the speckle pattern. In the present study the static states of woven fabric surfaces were obtained as the autocorrelation functions from the speckle patterns. The functions indicate the following: 1) By the reflection method the surface configuration of a woven fabric can be determined; by the transmission method the state of plane arrangement of yarn can be determined. 2) Three funda mental weaves (plain weave, twill weave, and satin weave) can be discriminated. 3) The presence and sizes of periodic defects in the woven fabric can be detected.