is their a problem with the blurring filter in the given code?? the image as a result is divided into 4 blocks which are out of order....... how can i blur it properly?
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i m trying to blur an image and then deblur it using a wiener filter that i created. but the blurred image shows unexpected results. it appears the image is getting divided into blocks which are then arranged out o order. what's the issue.?
i am trying to create a wiener filer to blur the image. i use a low pass LSI filter and then add gaussian noise to the blurred image. i assume the expected noise to be white and hence has a flat spectral density.
but before i can create by wiener filter to deblur it, the blurring filter(h) gives unexpected results. i am highlighting in bold letters the portion i assume is creating the problem. will the code not workfor those images for which number of rows is not eual to number of columns? in any case, its not working i guess when rows = columns either......please help me in correcting the error. in my code:
h=low pass filter
Snn=noise power
Suu = signal power
Code:
% function wien2(name,xdim,No,Snn)
%
% name = 'input image' (as in 'lenna.256')
% xdim = x dimension of input image (usually 256 or 512)
% No = Variance of Noise
% Snn = Power Spectral Density of Noise (Assumed White)
%
% This function takes an input image, runs it through a LSI filter h,
% and adds Gaussian noise to it. The MSE between the degraded and
% original image is then calculated. Weiner Filtering is then performed
% (using known h) and the degraded image is restored using
% the filter. The MSE between the restored and original image is then
% calculated and returned. Snn is set to a constant (assumes white noise)
%
No = 80;
% Load and Plot image
pict = imread('C:\Documents and Settings\All Users\Documents\My Pictures\Matlab pics\planet.png');
pict=rgb2gray(pict)
;
[xdim xdim]=size(pict)
;
clf
subplot(221)
imagesc(pict);
colormap(gray);
txt = ' before degradation';
title(txt)
axis square
axis off
*% Create LSI degradation model, need it to be phaseless
hi = 3.5^(-2);
h = zeros(256);
xl = 4;
xh = xdim - xl + 2;
h(1:xl,1:xl) = hi;
h(xh:xdim,1:xl) = hi;
h(1:xl,xh:xdim) = hi;
h(xh:xdim,xh:xdim) = hi;
% Create Gaussian noise, mean = 0, variance comes from input (No)
noise = sqrt(No)*randn(xdim,xdim);
% Run image through LSI Filter and then add noise
dpict = imfilter(pict,h);
dpict =double(dpict)+noise;
% Plot degraded image
subplot(222)
imagesc(dpict);
colormap(gray);
txt = [' with additive Gaussian Noise (mean=0, var=' , num2str(No), ')'];
title(txt)
axis square
axis off
1 件のコメント
Sebastian Holmqvist
2012 年 7 月 18 日
This is exhausting to read. Please reformulate your question and format your code with the Code button.
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