A Review: Optical Methods That Evaluate Displacement
In the literature of methods utilized to recover displacement information encoded in images as gray levels, scalar fields, converting them into vectorial fields there are available alternative methods. This paper will focus in three methods, the most widely used method the image correlation method (DIC), the HARP method that has evolved from the field of bio-engineering and a more recent method that we can call optical signal analysis method (OSA) that has its foundation on the application on the theory of Optical Signal Analysis. Basic aspects of these three methods are presented in this Part I of the paper. To simplify a very complex subject, 2D versions of these method are discussed.
In Part I, the basic premises and developments of three different approaches to the experimental analysis of full field kinematics of the continuum are presented. This second part is devoted to an evaluation of certain performance characteristics of these methods by looking to the actual results obtained from their application to specific cases. A disk under diametrical compression is a specimen that presents some typical features that provide grounds for comparison of spatial resolution and accuracy because it has a known theoretical solution and can be modelled by a well-defined FE approach. Furthermore, numerous studies of this specimen exist due to its application to the Brazilian test to determine the fracture load of concrete. In the case of the HARP method there are solutions in the literature of heart studies that are available for comparison purposes. A fair comparison of different methods is a formidable task. The high complexity of each of the different methods, the number of variables in play in each of the steps of a given approach, algorithms details, selection of scales makes it very difficult to provide definitive answers. The observation extracted from the results of this Part II of the paper can be considered as a first step in a required more comprehensive study. No matter the pointed difficulties, the obtained result provides a glimpse to basic aspects of spatial resolution, noise content coming from random errors and biased errors.
KeywordsDisplacement information Optical signal analysis Digital image correlation Harmonic phase method
- 1.Bedrosian, E.: A Product Theorem for Hilbert Transforms. Memorandum RM-3439-PM. The Rand Corporation, Santa Monica, CA (1962)Google Scholar
- 7.Sutton, M.A., Orteu, J.J., Schreier, H.: Image Correlation for Shape, Motion and Deformation Measurements: Basic Concepts, Theory and Applications. Springer, New York (2009)Google Scholar
- 8.Sutton, M.A., Reu, P.L. (eds.): International Digital Imaging Correlation Society, Conference Proceedings of the Society for Experimental Mechanics Series, 2016. New York, Springer (2017)Google Scholar
- 10.McVeigh, E.: MRI of myocardial function: motion tracking techniques. Magn. Reson. Med. 14(2), 137–150 (1997)Google Scholar