Mathematical Morphology Guided Automatic Unwrapping Isoclinic Phase Map in White Light Photoelasticity Liu, Xiaomeng; Dai, Shuguang;
By comparing the results calculated by atan() and atan2() functions, the correctly estimated region of isoclinic phase map is determined using morphological techniques. The isoclinic phase map is automatically unwrapped in the true phase range -π/2 to π/2. Demonstrations of the method on a disc and a ring under diametral compression are performed. Test results compare well with the theoretical results. Furthermore, the influences of principal stress direction and the range of isoclinic phase upon stress separation are discussed.
K. Ramesh, Digital Photoelasticity Advanced Techniques and Applications (Springer-Verlag Berlin Heidelberg, Germany, 2000), Chapter 1.
D. Brewster, "On the communication of the structure of doubly refracting crystals to glass, muriate of soda, flour spar and other substances by mechanical compression and application," Philosophical Transactions of the Royal Society, 156-178 (1816).
X. Liu and S. Dai, “Cubic polynomial curve-guided method for isochromatic determination in three-fringe photoelasticity,” Chinese Optics Letters 13, 101202 (2015).
G. M. Brown and J. L. Sullivan, “The computer aided holophotoelastic method,” Experimental Mechanics 30, 135-144 (1990).
G. Petrucci, “Full-field automatic evaluation of an isoclinic parameter in white light,” Experimental Mechanics 37, 420-426 (1997).
Z. Lei, D. Yun, and W. Yu, “Whole-field determination of isoclinic parameter by five-step colour phase-shifting and its error analysis,” Optics and Lasers in Engineering 40, 189-200 (2003).
M. Ramji, V. Y. Gadre, and K. Ramesh, “Comparative study of evaluation of primary isoclinic data by various spatial domain methods in digital photoelasticity,” Journal of Strain Analysis in Engineering Design 45, 333-348 (2006).
K. Ramesh, M. P. Hariprasad, and V. Ramakrishnan, “Robust multidirectional smoothing of isoclinic parameter in digital photoelasticity,” Opt. Eng. 54, 081205-1~081205-9 (2015).
A. Ajovalasit, G. Petrucci, and M. Scafidi, “Phase shifting photoelasticity in white light,” Optics and Lasers in Engineering 45, 596-611 (2007).
K. Ramesh, T. Kasimayan, and B. N. Simon, “Digital photoelasticity - A comprehensive review,” Journal of Strain Analysis in Engineering Design 46, 245-266 (2011).
M. Ramji, E. Nithila, K. Devvrath, and K. Ramesh, “Assessment of autonomous phase unwrapping of isochromatic phase maps in digital photoelasticity,” Sādhanā 33, 27-44 (2008).
P. Siegmann, D. Backman, and E. A. Patterson, “A robust approach to demodulating and unwrapping phase-stepped photoelastic data,” Experimental Mechanics 45, 278-289 (2005).
P. Pinit and E. Umezaki, “Digitally whole-field analysis of isoclinic parameter in photoelasticity by four-step color phase-shifting technique,” Optics and Lasers in Engineering 45, 795-807 (2007).
M. Ramji and K. Ramesh, “Whole field evaluation of stress components in digital photoelasticity-Issues, implementation and application,” Optical and Lasers in Engineering 46, 257-271 (2008).
M. Ramji and K. Ramesh, “Adaptive quality guided phase unwrapping algorithm for whole-field digital photoelastic parameter estimation,” Strain 46, 184-194 (2010).
T. Kasimayan and K. Ramesh, “Adaptive smoothing for isoclinic parameter evaluation in digital photoelasticity,” Strain 47, 371-375 (2011).
W. K. Pratt, Digital Image Processing (John Wiley and Sons, Inc., New York, USA, 2001), Chapter 14.