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Digital holography is a new imaging technique, which is developed on the base of optical holography, Digital
processing, and Computer techniques. It is using CCD instead of the conventional silver to record hologram, and then
reproducing the 3D contour of the object by the way of computer simulation. Compared with the traditional optical
holographic, the whole process is of simple measuring, lower production cost, faster the imaging speed, and with the
advantages of non-contact real-time measurement. At present, it can be used in the fields of the morphology detection of
tiny objects, micro deformation analysis, and biological cells shape measurement. It is one of the research hot spot at
home and abroad.
This paper introduced the basic principles and relevant theories about the optical holography and Digital holography, and
researched the basic questions which influence the reproduce images in the process of recording and reconstructing of
the digital holographic microcopy. In order to get a clear digital hologram, by analyzing the optical system structure, we
discussed the recording distance and of the hologram. On the base of the theoretical studies, we established a
measurement and analyzed the experimental conditions, then adjusted them to the system. To achieve a precise
measurement of tiny object in three-dimension, we measured MEMS micro device for example, and obtained the
reproduction three-dimensional contour, realized the three dimensional profile measurement of tiny object. According to
the experiment results consider: analysis the reference factors between the zero-order term and a pair of twin-images by
the choice of the object light and the reference light and the distance of the recording and reconstructing and the
characteristics of reconstruction light on the measurement, the measurement errors were analyzed. The research result
shows that the device owns certain reliability.
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