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灞曞紑鍏ㄩ儴For the double-pulse laser irradiation method to obtain the transient filter denoising of digital speckle image data processing method of research to achieve in a very short time interval on the accuracy of the instantaneous displacement field solution.
Speckle fringe images of particles there is a strong random noise, to extract the centerline of the image speckle fringe great bias, therefore removing the impact of particles of random noise and enhance speckle ESPI fringe images of data image processing key. Due to two double-pulse transient coherent speckle brightness differences between images, resulting in poor signal to noise ratio interference pattern, there is strong background noise, so for the double-pulse transient speckle interference pattern de-noising filter is critical Although the speckle image denoising filtering has become very many ways, but each method there are deficiencies, has become a plague transient electronic speckle measurement bottleneck problem.
Wavelet Transform and FFT window filtering method can be striped in different resolutions according to the density and distribution of the noise characteristics of de-noising, but also has the role of edge enhancement, Tsinghua University, two-dimensional discrete orthogonal wavelet transform has been successfully used for digital related filtering process, while the window FFT filtering method is an emerging method, yet more practical application.
The project to build double-pulse transient by experiment speckle test system, collecting the transient speckle interference pattern, and two-dimensional discrete orthogonal wavelet transform method and the emerging window of FFT filtering method is introced into the process of filtering method in two between the results a comparative analysis with traditional median filtering method for comparison of results of the orthogonal wavelet transform and FFT window filtering method validation and evaluation, access to evaluation findings.
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灞曞紑鍏ㄩ儴Scattered speckle of transient figure image wave filtering gaining specifically for pair of pulse lasers irradiate way accuracy goes and chirping to carry out the data handling method carrying out the field studying , realizing within extremely short period to microtime displacement finds the solution. Distribute the noise there being existing the intense pellet random in speckle streak image middle , bring very big deviation, to very big deviation the centre line extracting the scattered speckle streak image's, therefore, dislodging pellet random noise effect , strengthening the scattered speckle streak image is the key that the ESPI data image handles. The two pulse transient distributes a speckle since between pertinent two images the existence brightness difference, leads to interference design signal-to-noise ratio difference, existence very strong background noise, wave filtering intervening design therefore specifically for the two pulse transient distributes a speckle go and chirp extraordinary key, besieges the bottleneck problem winding scattered speckle of transient electron measurement though the wave filtering place of go and chirping to there be existing deficiency in very diversified method , but every kind of method taking form at present already distributing the speckle image, already has become. Minor wave alternation and window FFT wave filtering method are equal but the density and noise being based on a streak under the resolution ratio in diversity distribution characteristic goes to chirp, have the enhanced effect of border at the same time, the minor already with two-dimensional straggling orthogonality wave shifts success in Tsinghua University being used for pertinent figure wave filtering process middle , FFT wave filtering method belongs to but Xin Xing method in the window , has not gained more actual application. The project puts up capital by the experiment building scattered speckle of two pulse transient pilot system , collect the scattered speckle of transient intervening design, small wave alternation method and Xin Xing with two-dimensional straggling orthogonality together window FFT method leads into wave filtering process , the comparison being in progress between two kinds wave filtering method result analyses , method go along small wave alternation and window FFT wave filtering to orthogonality verifies and estimates that and comparing with the tradition middle value wave filtering method result go along,gain the conclusion estimating that.