Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Measurement and analysis of microtopography using wavelet methods

: Recknagel, R.-J.; Notni, G.


Gorecki, C. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.; European Optical Society -EOS-:
Optical inspection and micromeasurements II : Conference held as a part of the European Symposium on Lasers and Optics in Manufacturing, 16-19 June 1997, Munich
Bellingham, Wash.: SPIE, 1997 (SPIE Proceedings Series 3098)
ISBN: 0-8194-2518-4
European Symposium on Lasers and Optics in Manufacturing <1997, München>
Conference "Optical Inspection and Micromeasurements" <1997, München>
Fraunhofer IOF ()
fractal; roughness; surface; wavelet transformation; white light interferometry

Several methods for the analysis of white light interferograms are presented and their performance is compared to a new method employing the wavelet transform in connection with sub-Nyquist sampling. As the result of computer simulations and experiments the wavelet method proves to be best suited to the problem. Furthermore, a method is proposed to characterise the microtopography of surfaces on the basis of fractal parameters, whereby these parameters (Hausdorff-Besicovitch dimension D, for example) are calculated by means of a wavelet method. The advantages of using wavelets in comparison to the well known fractal description by means of the power spectral density is, that this new method is less affected by noise and offers the ability to separate the roughness from the structure. Simulations show that even in the otherwise disturbing presence of sharp edges or spikes the separation of micro and macro structure is successfully performed by the proposed wavelet method.