Design of decimation-free directional filter bank and its application in medical image enhancement
Feng Yang · Signal Processing · 2009
The paper presents a new directional analysis tool namely decimation-free directional fiher banks and their operators, as well as applies the operators to medical image enhancement.It integrates multilevel filter banks into single level filter bank and trans-forms all directional filters in frequency domain into spatial operators with the size of w×w.Each subhand image with the same size as the input image can be obtained by convolving input image with each operator.We can get enhanced image according to the statistical character of all subband images.Artifacts due to aliasing and folding during downsampling are avoided in decimation-free directional filter bank due to absence of decimators.No interpolation prior to image synthesis is required,so artifacts produced due to interpolation can be avoided.Results proved that using directional information can reduce image blurring.The method outperforms other classical methods in terms of visual quality,especially in texture images.