Speckle Noise Reduction in Ultrasound Images Using Wavelets: A Review
نویسنده
چکیده
Biomedical images are generally corrupted by speckle noise and Gaussian noise. Speckle noise is multiplicative type whereas other noises like Gaussian noise are additive type. It is difficult to remove multiplicative noise from images. We have presented various techniques for removing speckle noise from images and image enhancement by thresholding using various spatial domain filters and Wavelet analysis on the corrupted images have been discussed. Latest domain in the field of Image denoising and compression is using wavelet analysis. Multiresolutional image analysis using wavelets is the latest modification in the field of image enhancement and denoising. Wavelet analysis represents the next logical step: a windowing technique with variable-sized regions. Wavelet analysis allows the use of long time intervals where we want more precise low-frequency information, and shorter regions where we want high-frequency information. Speckle Noise is the high frequency content in the ultrasound images and can be easily removed using wavelet based thresholding technique. This paper presents study of various techniques for removal of speckle noise from images, used in biomedical applications, such as Spatial and frequency domain filter and a modified algorithm for speckle noise reduction using wavelet based multiresolutional analysis and thresholding function has been proposed incorporating different wavelets such as Haar, Coiflets and
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