RT Journal Article T1 Phase measuring algorithm for extraction of isochromatics of photoelastic fringe patterns A1 Quiroga Mellado, Juan Antonio A1 González Cano, Agustín AB In recent years phase-measuring techniques have been applied to the problem of extracting information of photoelastic data. We present a new phase-measuring algorithm for extraction of the isochromatics of photoelastic fringe patterns. The algorithm permits the extraction of the isochromatic phase with almost no influence from the isoclinics, thus avoiding the usual problems of low-modulation areas associated with isoclinics. The isochromatic phase map obtained with this algorithm is well suited for a full separation of the stress components in a sample. The algorithm can be used with any commercial diffuse-light circular polariscope. PB The Optical Society of America SN 0003-6935 YR 1997 FD 1997-11-10 LK https://hdl.handle.net/20.500.14352/58799 UL https://hdl.handle.net/20.500.14352/58799 LA eng NO 1. M. M. Frocht, Photoelasticity (Wiley, New York, 1941 and 1948). 2. J. Carazo-Álvarez, S. J. Haake, and E. A. Patterson, “Completely automated photoelastic fringe analysis”, Opt. Laser Eng. 21, 133–149 (1994). 3. T. Franz, A. Maidhof, and J. Sun, “Verfahren und Vorrichtung zur Bestimmung der Isochromatenwerte in der Spannungsoptik”, German patent DE-195 03 851 A1 (10 August 1995). 4. G. M. Brown and J. L. Sullivan, “The computer aided holo-photoelastic method: theory and experiment”, in Proceedings of SEM conference on Hologram Interferometry and Speckle Metrology, Baltimore, 5–8 November 1990 (Society for Experimental Mechanics, Bethel, Conn., 1990), pp. 102–109. 5. C. Buckberry and D. Towers, “Automatic analysis of isochromatic and isoclinic fringes in photoelasticity using phase-measuring techniques”, Meas. Sci. Technol. 6, 1227–1235 (1995). 6. R. Wernicke, K. P. Gründer, J. Munschau, and W. Winde, “A computer-aided photoelastic measuring system”, in Fringe ’93, Proceedings of the 2nd International Workshop on Automatic of Fringe Patterns, W. Jüptner and W. Osten, eds. (Akademie Verlag, Berlin, 1993), pp. 276–281. 7. A. Asundi, “Phase shifting in photoelasticity”, Exp. Tech. 17, 19–23 (1993). 8. E. A. Patterson and Z. F. Wang, “Towards full field automated photoelastic analysis of complex components”, Strain 27, 49–53 (1991). 9. A. V. S. S. R. Sarma, S. A. Pillai, G. Subramanian, and T. K. Varadan, “Computerized image processing for whole-field determination of isoclinics and isochromatics”, Exp. Mech. 32, 24–29 (1992). 10. Y. Otani, T. Shimada, T. Yoshizawa, and N. Umeda, “Two-dimensional birefringence measurement using the phase shifting technique”, Opt. Eng. 33, 1604–1609 (1994). 11. Frames-DT 2.1 Reference Guide (Steinbichler Optotechnik GmbH, Neubeuern, Germany, 1995). 12. D. Ghiglia, G. A. Mastin, and L. A. Romero, “Cellular-automata method for phase unwrapping”, J. Opt. Soc. Am. A 4, 267–279 (1987). 13. J. E. Greivenkamp and J. H. Bruning, “Phase-shifting interferometers”, in Optical Shop Testing, 2nd ed., D. Malacara, ed. (Wiley, New York, 1992), pp. 522ff. NO © 1997 Optical Society of America.We thank Hans Steinbichler of Steinbichler-Optotechnik GmbH and all the people there for their encouragement and technical assistance during the development of this study. Also, we thank Eusebio Bernabeu, director of the Optics Department of Universidad Complutense, for his help and continuous support. This research has been partly supported by a post-doctoral grant from the Ministerio de Educación y Ciencia of Spain. NO Ministerio de Educación y Ciencia of Spain DS Docta Complutense RD 7 may 2024