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OWT SURE-LET SOFTWARE FOR MATLAB
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Florian Luisier, Thierry Blu and Michael Unser
Biomedical Imaging group 
Swiss Federal Institute of Technology Lausanne (EPFL), Switzerland.
March 2007

This software implements the algorithm described in: 

[1] F. Luisier, T. Blu, M. Unser, "A New SURE Approach to Image
Denoising: Interscale Orthonormal Wavelet Thresholding," 
IEEE Transactions on Image Processing, vol. 16, no. 3, pp. 593-606, 
March 2007.

A. TEST PROGRAM

DENOISING_DEMO: Denoising demonstration based on the SURE-LET principle applied to interscale orthonormal wavelet thresholding. 
To run this script, just type 'denoising_demo' in your Matlab Command Window.
Note that the core of this demo is the denoising step that is performed by the command: 

	output = OWT_SURELET_denoise(input,wtype,sigma);

B. FFT-BASED WAVELET TRANSFORM FUNCTIONS

FFT_WAVEFILTERS: Computes the frequency responses of the wavelet 
analysis and synthesis filters (lowpass and highpass) for various types 
of filters.

FFT_GDC_FILTER: Computes the frequency response of the Group Delay
Compensation (GDC) filter associated to a particular orthonormal wavelet filter.

FFT_WAVEDEC: Performs a FFT-based computation of the wavelet 
transform of a 2D signal of size [Nx,Ny] to a given depth [Jx,Jy]. At least one dimension of the signal must be even.

FFT_WAVEREC: Performs a FFT-based computation of the inverse 
wavelet transform.

C. DENOISING FUNCTIONS

OWT_SURELET_DENOISE: Removes addtitive Gaussian white noise using the inter-scale SURE-LET principle in the framework of an orthonormal wavelet transform (OWT) only. The wavelet transform is included in the process.

FCN_MIN_SURE: Removes addtitive Gaussian white noise inside a given wavelet subband by minimizing the SURE, as described in [1].

D. OTHER AUXILIARY ROUTINES

AUX_GAUSSIAN_SMOOTHING: Applies a normalized 2D Gaussian kernel on a 2D signal.

AUX_DYADIC_MAX_SCALES: Computes the maximum number of dyadic scales.

AUX_NUM_OF_ITERS: Computes the most suitable number of iterations to be performed in the OWT SURE-LET algorithm.

The folder also contains some standard test images.

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Please, report any bugs, comments or suggestions to:
florian.luisier@epfl.ch 
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