04145140 is referenced by 28 patents and cites 1 patents.

A method and apparatus for measuring surface roughness, waviness, cracks or any irregularities or flatnesses in a surface utilizing statistical properties of dichromatic speckle patterns. In practice surface roughness is normally measured utilizing standard profile measuring devices. However, these instruments are not efficient in practice in view of their slowness for effecting measurements. The present invention provides an improved method of measuring surface roughness including the following steps; generating a spatially coherent polychromatic light having at least two wavelengths and directing the light at an optically rough surface in order to illuminate the same; analyzing intensity variations in two speckle patterns formed at a plane due to two wavelengths of the polychromatic light; and defining and evaluating a difference between intensities of the two speckle patterns as a function of surface roughness of the optically rough surface.

Title
Measurement of surface roughness
Application Number
5/806708
Publication Number
4145140
Application Date
June 15, 1977
Publication Date
March 20, 1979
Inventor
Hitoshi Fujii
770 Belmont, Apt. 106, Ste-Foy, Quebec City, Quebec
CA
Agent
Charles E Brown
IPC
G01B 9/02
View Original Source