WIENER_FILTER_CVIP

wiener_filter_cvip() - performs the Wiener restoration filtering.

SYNTAX
DESCRIPTION
REFERENCE
Example
CREDITS

SYNTAX

  Y = wiener_filter_cvip(d,h,cutoff,limitGain,noiseImage,originalImage)

Input Parameters Include :

d - The degraded image. A single or multiband image.

h - The degradation function. It can be single band.

cutoff - Cutoff frequency for filtering.

limitGain - Sets the maximum gain using the DC value as a baseline. limitGain=1 --> DC value is the maximum gain. limitGain>1 --> DC_value*limitGain is the maximum gain.

noiseImage - The noise image.It can be single band.

originalImage - The original image. A single or multiband image. The number of bands should match with the input 'd'.

Output Parameter Include:

Y - The output image after restoration filtering.

DESCRIPTION

This function performs the wiener filter restoration operation on an input degraded image to restore it to its original state. The wiener filter response increses as the signal-to-noise ratio of the image increases. As, the signal-to-noise ratio of the image starts to decrease, the wiener filter response also starts to decrease eventually reaching zero. Thus, the filter attenuates all the noise present in the image and boosts only the image signal. The function applies the filter by multiplying it to the Fourier transform of the degraded image and obtains the restored image by taking the inverse transform of the resultant image from the filtering operation.

REFERENCE

1. Scott E Umbaugh. DIGITAL IMAGE PROCESSING AND ANALYSIS: Applications with MATLAB and CVIPtools, 3rd Edition.

Example

% Read Image

 originalImage = imread('butterfly.tif');

% degraded image

 d = imread('Butterfly.gaussian.tif');

% noise image

 noiseImage = imread('Butterfly.gaussian.tif');

% Cuttoff frequency

 cutoff =32;

% limit gain

 limitGain = 10;

% degradation function.

 h = [ 2.50 4.500 2.250 :4.500 9.001 4.500 : 2.250 4.500 2.250];

% call function

 Y = wiener_filter_cvip(d,h,cutoff,limitGain,noiseImage,originalImage);

% Display input image

 figure;imshow(originalImage);title('Input Image');

 figure;imshow(d);title('Input Degraded Image');

 figure;imshow(noiseImage);title('Input noise Image');

% Display output image

 figure;imshow(remap_cvip(Y));title('Output Image');

ans =

    0.0027


ans =

    0.0028


ans =

    0.0047

WIENER_FILTER_CVIP

Contents

SYNTAX

DESCRIPTION

REFERENCE

Example

CREDITS