Comparative study of the efficiency of noise-proof algorithms in improving the contrast of speckle interferograms registered by the time-average method

A noise-proof algorithm for post-processing of video files recorded without isolation from vibration in the optical scheme of a digital speckle interferometer with a continuous laser and a diffuse-scattering element placed in front of the object is proposed. The results of the proposed algorithm are compared with the results of the known method for processing of a video stream in real time which is based on the sequential determination of residual images with their subsequent accumulation. The possibility of the contrast improvement by 19 – 48% compared to the basic method for the resulting speckle interferograms obtained by post-processing is shown. The developed algorithm was verified during a study of natural vibration modes of the vibrating blade of a gas turbine engine.