In digital holography holograms are recorded by a CCD camera and images are reconstructed by a computer. Resolution of CCD is much lower than photographic materials to limit object size and image quality. This issue has been overcome by phaseshifting digital holography that derives the complex amplitude of object wave is directly derived by the phase shifting technique in inline setup which reduces the spatial frequency of the interference patterns on the CCD. This technique enables to record and reconstruct larger objects than in the conventional technique using off-axis setup. After image formation is explained, applications to interferometry are discussed. Since phase distribution at the object surface is directly derived in reconstruction, we only have to carry out phase-unwrapping to obtain distribution of surface height or displacement. For surface contouring we calculate the difference of the reconstructed phases before and after small tilt of the object illuminating beam. We attained an accuracy of 30μm using a wavelength of 633nm. Object size is limited by the ratio of wavelength to pixel pitch in the case of free space setup. We eliminated this limit by introducing a lens to image an object on to a CCD and could measure objects with the size of more than 10 centimeters.

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Various implants are employed to provide osteosynthesis of the trochanteric fracture of femur. However, pain due to the stress concentration in the bone and new fracture are caused, when the implant does not physically suit the patient. Therefore, detailed analysis of femoral deformation before and after implantation is important in clinical medicine and implant design. The purpose of this study is to evaluate the mechanical properties between fixation implant devices of different designs by holographic interferometry. The technique is a contactless whole-field method that is ideally suited to analyzing the deformation characteristics of complex structures such as the femur. A mechanically analogous composite femur, made from a glass fiber epoxy composite, was used to reduce variability between specimens. In this paper, the deformation of IMHS and Gamma AP in which the design differs in intramedullary nailing system was investigated. Still, the result of finite element analysis and experiment agreed qualitatively well on the deformation of the intact femur.

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A method for determining stress intensity factor automatically from displacement fields obtained by digital image correlation is proposed. In order to perform automatic and accurate evaluation, not only stress intensity factor but crack tip location and higher order terms in the series expansion of displacement fields are determined simultaneously in the present study. The nonlinear least-square approach based on Newton-Raphson method is applied to obtain all unknowns. The effectiveness of the method is demonstrated by applying the proposed method to mode I crack problem in a strip plate with a semi-infinite crack. Since stress intensity factor can be evaluated easily, simply and automatically by the technique with digital image correlation, it is expected that the proposed method can be applied to various fracture problems.

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