Image Enhancement Statistical Filters (i) Mean and Median Filters (ii) Max-min and Min-max Filters

clc;clear all;close all;

% =========================================

%               Mean Filter

% =========================================

f = imread('saturn.tif');

subplot(2,2,1);

imshow(f);

title('Original Image');

m = mean2(double(f));

g = imfilter(f,m);

k = imabsdiff(f,g);

subplot(2,2,2);

imshow(g);

title('Mean Filtered Image');

subplot(2,2,3);

imshow(k);

title('Absolute Difference of f ang g');

% =========================================

%               Median filter

% =========================================

figure;

f = imread('saturn.tif');

g = imnoise(f,'salt & pepper',0.06);

subplot(1,2,1);

imshow(g);

title('Input Image');

%K = filter2(fspecial('average',3),g)/255;

M = medfilt2(g,[3 3]);

%figure, imshow(K)

subplot(1,2,2);

imshow(M);

title('Median filtered image');

% =========================================

%               Minimax filter

% =========================================

figure;

f = imread('saturn.tif');

subplot(1,2,1);

imshow(f);

title('Original Image');

n = 5;                  % Filter order

freq = [0 0.4 0.5 1];   % Frequency band edges

a = [1  1  0  0];       % Desired amplitudes

b = remez(n,freq,a);

L = imfilter(f,b);

subplot(1,2,2);

imshow(L);

title('Mini-max Filtered Image');

Mean

Median

Min-Max