Digitally whole-field analysis of isoclinic parameter in photoelasticity by four-step color phase-shifting technique

Pinit, Pichet; Umezaki, Eisaku

doi:10.1016/j.optlaseng.2006.12.005

Cited by 78 publications

(38 citation statements)

References 26 publications

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“…Thus the PSM in white light has been used by several researchers [11][12][13] in order to determine the isoclinic parameter, minimizing the interaction between isochromatics and isoclines and avoiding the use of light sources of several wavelengths [14]. Some authors [15] have shown that the spectral content of the light source influences the retardation and the isoclinic parameter, determined using a monochrome camera.…”

Section: Introductionmentioning

confidence: 99%

Review of RGB photoelasticity

Ajovalasit

Petrucci

Scafidi

2015

Optics and Lasers in Engineering

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Section: Introductionmentioning

confidence: 99%

Review of RGB photoelasticity

Ajovalasit

Petrucci

Scafidi

2015

Optics and Lasers in Engineering

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“…The values of  i and  i are calculated by the new equation. In the analysis of the error, only the zones within the photos that were unambiguous and contained no inconsistencies were considered [18][19][20]. Fig.…”

Section: Testing and Analysis Of Errormentioning

confidence: 99%

Separation of Isochromatics and Isoclinics Phasemaps for the Photoelastic Technique with use Phase Shifting and a Large Number of High Precision Images

Magalhães¹,

Neto²,

Júnior³

et al. 2013

Metrology and Measurement Systems

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Digital photoelasticity is an important optical metrology follow-up for stress and strain analysis using full-field digital photographic images. Advances in digital image processing, data acquisition, procedures for pattern recognition and storage capacity enable the use of the computer-aided technique in automation and facilitate improvement of the digital photoelastic technique. The objective of this research is to find new equations for a novel phase-shifting method in digital photoelasticity. Some innovations are proposed. In terms of phaseshifting, only the analyzer is rotated, and the other equations are deduced by applying a new numerical technique instead of the usual algebraic techniques. This approach can be used to calculate a larger sequence of images. Each image represents a pattern and a measurement of the stresses present in the object. A decrease in the mean errors was obtained by increasing the number of observations. A reduction in the difference between the theoretical and experimental values of stresses was obtained by increasing the number of images in the equations for calculating phase. Every photographic image has errors and random noise, but the uncertainties due to these effects can be reduced with a larger number of observations. The proposed method with many images and high accuracy is a good alternative to the photoelastic techniques.

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“…Two well known phase shifting algorithms [6,7] are considered for the calculation of the isoclinic parameter -the Wang-Patterson algorithm and the Pinit-Umezaki algorithm which are formulated by circular and plane polariscope respectively and with their isoclinic calculations listed as Eq. (1) …”

Section: Isoclinic Formulationmentioning

confidence: 99%

“…(1) and (2), respectively) simultaneously existing in the numerator and denominator of the above equations and that could cause undefined region when their values approach zero. Pinit and Umezeki [7] suggested a multi-wavelength compensation method which will be adopted in the following isoclinic calculation to circumvent the undefined problems mentioned above. Fig.…”

Section: Isoclinic Formulationmentioning

confidence: 99%

“…Thus, any isoclinic phase ambiguity would result in the phase inconsistencies of isochromatic calculation and cause problems and difficulties of its retrieval. Many methods [1][2][3] have been proposed to unwrap these kinds of isochromatic fringes with phase ambiguities. Lots of treatments are needed to circumvent the aforementioned ambiguity problems to do the retrieval.…”

Section: Introductionmentioning

confidence: 99%

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Isoclinic Ambiguity Unwrapping of Circular Ring under Diametric Compression

Huang

2010

EPJ Web of Conferences

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Abstract. Isoclinic and isochromatic parameters in photoelastic analysis are formulated by arc tangent function of several phase shifting frames but for isochromatic calculation it is, in addition, in terms of isoclinic data also. Thus, any isoclinic phase ambiguity would also result in the phase inconsistencies of isochromatic calculation and cause unwrapping problems and difficulties. Many methods had been proposed to treat these kinds of isochromatic fringes but lots of treatments were needed for the correct retrieval. In this work, the isoclinic ambiguity problem is investigated and solved directly by a novel regional phase unwrapping technique. Once the isoclinic phase ambiguity problems are solved, a correct isoclinic result can be obtained. Then, substituting this result into the isochromatic formation yields an ambiguity free isochromatic phase map, which can be easily restored by any phase unwrapping algorithm. A stress frozen sample -circular ring under diametric compression verifies its effectiveness. Usually happened is that this kind of sample is with ambiguous isoclinic data which would cause phase ambiguities of the isochromatic formulation if not treated well first.

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Digitally whole-field analysis of isoclinic parameter in photoelasticity by four-step color phase-shifting technique

Cited by 78 publications

References 26 publications

Review of RGB photoelasticity

Review of RGB photoelasticity

Separation of Isochromatics and Isoclinics Phasemaps for the Photoelastic Technique with use Phase Shifting and a Large Number of High Precision Images

Isoclinic Ambiguity Unwrapping of Circular Ring under Diametric Compression

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