D Shape-based Digital Holographic Technology Research

Digital holographic technology is the combining product of computer technology and traditional optical holography, quite different from traditional optical holography. Digital holographic technology uses digital process to record and reconstruct hologram, which simplifies the process of recording and reconstruction of traditional optical holography, digital holographic technology can more easily get amplitude information as well as phase information, and the phase information is an important parameter for the reconstructing 3-D objects.This paper mainly studies 3-D topography recovery and panoramic reconstruction of objects based on digital holographic technology. Depending on the different sizes of object morphology recovery and resolution, recovery technology can be divided into the recovery of microscopic 3-D object and microscopic recovery of 3-D object. This paper adopts dual-wavelength optical phase unwrapping techniques to reconstruct micro-objects, using phase unwrapping algorithm restore macro-objects, and combining four-step phase shifting method, phase unwrapping algorithm and image mosaicing technique to realize panoramic reconstruction of object.This paper systematic studies technique based on dual-wavelength optics of phase unwrapping objects for morphology recovery. Detailed introduction of digital holographic imaging, double wavelengths topography measurement, and compared with single wavelength digital holographic technology, the results show that dual-wavelength optical phase unwrapping technology has advantages of a wider measurement range and algorithm simpler and so on. Experiments prove that, in micro-object morphology, dual wavelength optical phase unwrapping technology has higher accuracy of recovery and practicability.This paper studies in depth the basic principle of the mask and Fourier transform phase unwrapping algorithm, which improves traditional Fourier transform phase unwrapping algorithm, bringing the mask algorithm to process phase boundary and noise. Experimental results show that the comparison of mask and Fourier transform phase unwrapping algorithm and other phase unwrapping algorithm, the algorithm based on the mask and Fourier transform phase unwrapping algorithm can lead to the improvement of signal-to-noise ratio and computing speed.This paper combines digital holography, four-step phase shifting method, phase unwrapping algorithm and image mosaicing technique to realize panoramic reconstruction. Through computer simulation and experiments, this paper realizes panoramic reconstruction of 3-D object, reconstruction of 360-degree information of tested object. Experimental results verify feasibility and practicability of the four-step phase shifting digital holographic technology in the panorama reconstruction of 3-D object.