Development of a high resolution sensor for surface roughness.

Features of Electromagnetic Waves Scattering by Surface Fractal Structures

“…Hence a noncontact and more speed optical method would be attractive. Different optical noncontact methods for measuring surface roughness have been developed mainly based on reflected light detection, focus error detection, laser scattering, speckle and the interference method [4][5][6][7][8][9][10]. Some of these have good resolutions and are being applied in some sectors where mechanical measuring methods previously enjoyed clear predominance.…”

Confocal surface profiling utilizing chromatic aberration

“…Many methods of surface profiling utilizing noncontact, nondestructive optical techniques have been proposed, ranging from interferometric fringe-detection methods to astigmatic focus error detection methods (Fainman et al 1982, Laeri and Strand 1987, Lanfer et al 1986, Lou et al 1984, Makosch and Drolliger 1984, Mitsui et al 1988, Shiraishi 1980, Sommargen 1981. Optical surface profiling techniques can be broadly divided into two groups: the Fourier analysis techniques that give averaged properties of the surface; and the direct imaging techniques where every point is individually imaged.…”