The phase unwrapping algorithm based on sorting by reliability is used to process the digital hologram interferogram, which is easy to be affected by low reliability pixels, resulting in the distortion of the three-dimensional surface. In view of the above problems, the algorithm based on sorting by reliability is improved, and the appropriate threshold is defined, so the unwrapping path is optimized. The simulation results show that the optimized unwrapping algorithm can effectively unwrap the three-dimensional surface morphology of the target, and the results are smooth and without distortion.
Digital Holographic Microscopy (DHM) is the latest holographic technique, increasing the resolution by inserting a microscopic lens. In this paper, the non - contact measurement method of the dynamic ultrasonic wavefield on the surface is studied. Aiming at the characteristics of the continuous dynamic ultrasonic wavefield, a pulsed laser based DHM system is designed in this paper. The system consists of a pulsed nano-second laser, a CCD camera with short shutter time, high sensitivity and high SNR, a microscopic lens, a novel optical subsystem, and a synchronous control system. The performance of the designed DHM system is tested on the standard resolution test target and ultrasonic transducer. The results of the experiment show that the transient three - dimensional topography of the dynamic ultrasonic wavefield is measured at different moments and effectively.
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