DOI QR코드

DOI QR Code

Study on Algorithm of Micro Surface Roughness Measurement Using Laser Reflectance Light

레이저 반사광을 이용한 미세 표면 거칠기 측정 알고리즘에 관한 연구

  • 최규종 (부산대학교 정밀정형 및 금형가공연구소) ;
  • 김화영 (부산대학교 기계공학부) ;
  • 안중환 (부산대학교 기계공학부)
  • Published : 2008.04.01

Abstract

Reflected light can be decomposed into specular and diffuse components according to the light reflectance theory and experiments. The specular component appears in smooth surfaces mainly, while the diffuse one is visible in rough surfaces mostly. Therefore, each component can be used in forming their correlations to a surface roughness. However, they cannot represent the whole surface roughness seamlessly, because each formulation is merely validated in their available surface roughness regions. To solve this problem, new approaches to properly blend two light components in all regions are proposed in this paper. First is the weighting function method that a blending zone and rate can be flexibly adjusted, and second is the neural network method based on the learning from the measurement data. Simulations based on the light reflectance theory were conducted to examine its performance, and then experiments conducted to prove the enhancement of the measurement accuracy and reliability through the whole surface roughness regions.

Keywords

Micro surface roughness;Laser reflectance light;Weighting function;Neural network

References

  1. Satoru Takahashi, Takahashi Miyoshi, Yasuhiro Takaya and Yasufumi Tatsuno, 2002, 'Study on In-Process Measurement of Silicon Wafer Surface Defects by Laser Scattered Defect Pattern (2nd Report) . Fast Defect Measurement Method Method Using LSDP,' Japan Society of Precision Engineering, Vol. 68, No. 7, pp. 1431-1435 https://doi.org/10.2493/jjspe.68.1431
  2. Hiroshi Harad, Hideki Nakajima, Teruo Yamaguchi and Atsuhiko Noda, 2002, 'Optical Sensing of Surface Roughness for Polishing Robot (3Rd Report),' Japan Society of Precision Engineering, Vol. 68, No. 11, pp. 962-966 https://doi.org/10.2493/jjspe.68.962
  3. Seo, Y. H., Kim, J. N. and Ahn, J. H., 2004, 'Estimation of Specular Light Power by Adjusting Incident Laser Power for Measuring Mirror-Like Surface Roughness,' Journal of the Korean Society of Precision Engineering, Vol. 21, No. 6, pp. 94-101
  4. Beckmann, P. and Spizzichino, A., 1963, 'The Scattering of Electromagnetic Waves from Rough Surfaces,' Pergamon press, Oxford
  5. Nayar, Shree K., Ikeuchi, Katsushi, Kanade and Takeo, 1991, 'Surface Reflection: Physical and Geometrical Perspectives,' IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 13, No. 7, pp. 611-634 https://doi.org/10.1109/34.85654
  6. Seo, Y. H. and Ahn, J. H., 2004, 'Microscopic Surface Estimation Through Light Distribution Analysis of Reflected Laser Beam,' The 30th Annual Conference of the IEEE Industrial Electronics Society, Vol. 2, pp. 1924-1928 https://doi.org/10.1109/IECON.2004.1431878
  7. Draelos, T. and Hush, D., 1996, 'A Constructive Neural Network Algorithm for Function Approxim-ation,' Neural Networks, IEEE International Conference on, Vol. 1, pp. 50-55 https://doi.org/10.1109/ICNN.1996.548865