The deformation measurement mode was tested in Massachusetts Ear and Eye Infirmary (MEEI) in Boston. The temporal bone was from the left ear of a 65 year old male without history of otologic disease. The incus, the extended facial recess, the roof of the epitympanum, the Eustachian tube and the jugular bulb were all drilled away to expose the medial side of the TM. In Figure 6, the OH illuminated the medial side of TM with the back surface of TM perpendicular to the beam. The sound and microphone coupler was placed in the lateral side of TM through the wall of ear canal. A glass sheet was used to seal the ear canal in order to isolate the SPS. The TM was painted with ZnO to increase the contrast and mounted with the dental cement onto a hollow metal tube. Figure 7 shows the deformation of the medial side of TM at phase 180 at the sound excitation of 1 KHz. The location of the umbo is shown in the first image. It is clear to see there are two peaks generated and the scale of the deformation is around 1 micrometer. 4. CONCLUSIONS AND FUTURE WORK In this study, we are developing the dual-wavelength lensless digital holography system to measure both the shape and acoustically induced deformation of TMs. The typical feathers: (1) it is a collimated con-axial system, and (2) 3D displacements are calculated base on the single axis deformation and shape measurement. However, further research need to be completed in the future, such as the validation, repeatability and error estimation of the system, and simplifying and packaging the system. 5. ACKNOWLEDGMENT This work is supported by National Institutes of Health (NIH), Massachusetts Ear and Eye Infirmary (MEEI) and Worcester Polytechnic Institute (WPI). Thanks for the help from J. M. Flores-Moreno, Ellery Harrington, Ivo Dobrev, Michael Zervas, Peter Hefti and other group members in Center for Holographic Studies and Laser micro-mechaTronics (CHSLT). 6. REFERENCE [1] Hernandez-Montes, Maria del Socorro et al. “Optoelectronic holographic otoscope for measurement of nanodisplacements in tympanic membranes.” Journal of Biomedical Optics 14.3 (2009): 034023-9. [2] C. Furlong and R. J. Pryputniewicz, "Electro-optic holography method for determination of surface shape and deformation," in Laser interferometry IX: Techniques and Analysis, M. Kujawinska, G. M Brown, and M. Takeda, Eds., Proc. SPIE 3478, 86–97 (1998). [3] I. Yamaguchi, T. Ida, M. Yokota, and K. Yamashita, “Surface shape measurement by phase shifting digital holography with a wavelength shift,” Appl. Opt. 45, 7610-7616 (2006). [4] W. Osten, "Application of optical shape measurement for the nondestructive evaluation of complex objects," Opt. Eng. 39(1), 232–243 (2000) . 206
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