CT Image Denoising Using Double Density Dual Tree Complex Wavelet with Modified Thresholding

Due to low radiation dose and software fault, CT images are noisy. How to extraction of meaningful information from noisy CT images are challenging works. In this work, we present a new denoising algorithm for CT image using double density dual tree complex wavelet transform (DDCWT). Firstly, we use DDCWT decompose noisy CT image into high frequency and low frequency components. In the next, a modified threshold is used for DDCWT coefficient. Finally, the denoised image is obtained by reconstructing high frequency and low frequency components through inverse decomposition of DDCWT. Experimental results demonstrate that the improved DDCWT can maintain more rich details and have a higher practical value.

[1]  Ivan W. Selesnick,et al.  Symmetric nearly orthogonal and orthogonal nearly symmetric wavelets , 2004 .

[2]  Nick G. Kingsbury,et al.  The dual-tree complex wavelet transform: A new efficient tool for image restoration and enhancement , 1998, 9th European Signal Processing Conference (EUSIPCO 1998).

[3]  I. Johnstone,et al.  Adapting to Unknown Smoothness via Wavelet Shrinkage , 1995 .

[4]  Ivan W. Selesnick,et al.  Symmetric nearly shift-invariant tight frame wavelets , 2005, IEEE Transactions on Signal Processing.

[5]  Martin Vetterli,et al.  Adaptive wavelet thresholding for image denoising and compression , 2000, IEEE Trans. Image Process..

[6]  Mark J. Shensa,et al.  The discrete wavelet transform: wedding the a trous and Mallat algorithms , 1992, IEEE Trans. Signal Process..

[7]  Nick G. Kingsbury,et al.  Shift invariant properties of the dual-tree complex wavelet transform , 1999, 1999 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings. ICASSP99 (Cat. No.99CH36258).

[8]  David L. Donoho,et al.  De-noising by soft-thresholding , 1995, IEEE Trans. Inf. Theory.

[9]  N. Kingsbury.  Complex Wavelets for Shift Invariant Analysis and Filtering of Signals , 2001 .

[10]  Richard Baraniuk,et al.  The Dual-tree Complex Wavelet Transform , 2007 .

[11]  Wai-Kai Chen,et al.  Linear Networks and Systems , 1983 .

[12]  Nick G. Kingsbury,et al.  A dual-tree complex wavelet transform with improved orthogonality and symmetry properties , 2000, Proceedings 2000 International Conference on Image Processing (Cat. No.00CH37101).

[13]  I. Selesnick,et al.  Symmetric wavelet tight frames with two generators , 2004 .

[14]  Ivan W. Selesnick,et al.  Overcomplete Discrete Wavelet Transforms With Rational Dilation Factors , 2009, IEEE Transactions on Signal Processing.