Patent ID: 6553133
Filing Date: 2003-04-22
Classification: G01N,G06T

Abstract:
A method of characterizing a web of sheet material in four dimensions, said method comprising:(a) illuminating said web with light energy at a point substantially adjacent to the initial formation of said web; (b) recording an input image of said web at said point during said illumination; (c) converting said image to a digital representation thereof; (d) processing said digital representation to determine the homogeneity of said web at said point, said determination of said homogeneity comprises: generating a multiscale wavelet representation of said digital representation to generate detail signals; (e) processing said digital representation to determine the topography of said web at said point; (f) processing said digital representation to determine the depth profile of said web at said point; and (g) providing respective output signals representative of said homogeneity, said topography, and said depth profile; whereby said web can be characterized at said point in four dimensions.