Comparison of different approaches to suppress speckles in ultrasonic tomograms
Three methods were applied to ultrasonic tomograms: modified Wiener filtering, adaptive median filtering and averaging of images with speckles diversified by lateral shift of the scanhead. Of these, Wiener filtering seems to have the potential to enhance specular targets while partly suppressing the speckles without changing the overall image appearance strongly. The adaptive median is capable of suppressing the speckles in the greatest extent without smearing the edges but the final appearance of the images is rather unusual. The averaging gives interesting results as it does not distort the image (it is even capable of additional sharpening of structures smeared by insufficient lateral resolution) but the implementation of this approach is rather impractical.
KeywordsGall Bladder Distorted Image Wiener Filter Speckle Noise Adaptive Median
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