Image Noise Removing in DPIV Based on Wavelet Transform
小波变换应用于图象去噪

DPIV (Digital Particle-Imaging Velocimetry) has been attached importance to and applied wisely interiorly and overseas. But at present, its m ost difficult problem is the precision. Because the tracer particle images of DP IV are sampled by CCD and image digitizer, the noise (mainly the noise of partic le image size, the size of interrogation window, local velocity gradients, the n umber of particles within the sampling window and quantization effects) that is imported inevitably in the process of experiment falls the precision of DPIV exp eriment. This paper presents the image (simulative and practical image) noise re moving in DPIV based on wavelet transform whose characteristic is the multiresol ution. This method is compared with image noise removing by Wiener and median fi lter. The result shows that image noise removing in DPIV based on wavelet transf orm improves the precision of DPIV experiment, and it is the most precise to reb uild the velocity field based on cross-correlation after image noise removing i n DPIV using wavelet transform.