Publication de 4 numéros par an
ISSN Imprimer: 1065-3090
ISSN En ligne: 1940-4336
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NOISE REDUCTION METHOD IN FLOW VISUALIZATION USING DSPI
RÉSUMÉ
The recent development of digital speckle pattern interferometry (DSPI) makes it a powerful tool inflow visualization and diagnostics, but random speckle noise on a speckle interferogram makes it difficult to analyze by conventional techniques. For this reason, digital filters must be applied to reduce speckle noise. In this article, a new image-processing method of digital speckle interferograms is presented, which can reduce speckle noise effectively. This method is based on FFT and low-pass filter in the frequency domain. According to the feature of spectrum of speckle interferograms, useful information can be reserved as well as the high frequency noise removed. A low-pass filter is presented and, as a typical case, a speckle interferogram of a spirit-lamp flame is processed by this method. The result is preferable and the signal-to-noise ratio of the speckle interferogram is improved greatly, which indicates this method is practical and valuable in the visualization of thermal flow using DSPI.