Applications of digital image correlation to biological tissues

Abstract

Optical methods are becoming commonplace in investigations of the physical and mechanical behavior of biological tissues. Digital image correlation (DIC) is a versatile optical method that shows tremendous promise for applications involving biological tissues and biomaterials. We present the fundamentals of DIC with an emphasis on the application to biological materials. An approach for surface preparation is described that facilitates its application to hydrated substrates. Three examples are presented that highlight the use of DIC for biomedical research. The first example describes the use of DIC to study the mechanical behavior of arterial tissues up to 40% elongation. The second example describes an evaluation of the mechanical properties of bovine hoof horn in the dehydrated and fully hydrated states. Uniaxial tension experiments are performed to determine the elastic modulus (E) and Poisson's ratio (nu) of both the arterial and dermal tissues. Spatial variations in the mechanical properties are evident from the full-field characterization of both tissues. Finally, an application of DIC to study the evolution of loosening in cemented total hip replacements is described. The noncontact analysis enables measurement of the relative displacement between the bone/bone cement and bone cement/prosthesis interfaces. Based on the elementary optical arrangement, the simple surface preparation, and the ability to acquire displacement/strain measurements over a large range of deformation, DIC should serve as a valuable tool for biomedical research. Further developments will enable the use of DIC for in vivo applications.

Quality assessment of speckle patterns for digital image correlation

“…Several attempts were made to obtain an evenly distributed pattern of black paint drops. The same procedure is used in different studies in the case of actual experiments [14][15][16][17][18][19]. Three different images with a randomly chosen size of 250 × 500 pixels are extracted from this speckle pattern.…”

Optical coherence elastography – OCT at work in tissue biomechanics [Invited]

“…Such methods have also been developed for volumes, so-called digital volume correlation, which was first developed for X-ray computed tomography [168]. (As an aside, "speckle" in image correlation is sometimes not the coherent speckle we observe in OCT, but often describes the effect of imaging artificial texture applied to a sample surface [167,169].) Digital volume correlation methods have recently been applied to OCT [149,166], enabling measurement of the full strain tensor.…”

Experimental and numerical research of mechanical behaviour of titanium alloy hip implant

“…The method is also suitable for analysis of irregular object geometries made of various materials, as is often the case in biomedical applications. [2,19,20].…”