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clc;

clear all;

I=imread(‘eight.tif’);

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% %用中值滤波，多维滤波，使用中心为-4,-8的拉普

% %拉斯滤波器，高斯低通滤波，拉普拉斯滤波器进行滤波处理

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

figure;%figure1

subplot(2,2,1);

imshow(I);

title(‘原始图像’);

J=imnoise(I,’salt & pepper’,0.04);%加椒盐噪声

title(‘加椒盐噪声’);

subplot(2,2,2);

imshow(J);

K=medfilt2(J,[4,4])%进行中值滤波;

subplot(2,2,3);

imshow(K);

title(‘进行中值滤波’);

h=ones(3,3)/9;%多维滤波

w=h;

g=imfilter(I,w,’conv’,’replicate’)

subplot(2,2,4);

imshow(g);

title(‘多维滤波’);

%使用中心为-4,-8的拉普拉斯滤波器,

w4=[1 1 1;

1 -4 1;

1 1 1];

w8=[1 1 1;

1 -8 1;

1 1 1];

f=im2double(I);

g4=f-imfilter(f,w4,’replicate’);

g8=f-imfilter(f,w8,’replicate’);

imshow(f);

figure;%figure2

subplot(1,2,1);

imshow(g4);

title(‘中心为-4的拉普拉斯滤波’);

subplot(1,2,2);

imshow(g8);

title(‘中心为-8的拉普拉斯滤波’);

h3=fspecial(‘gaussian’,[3,3],0.5);%高斯低通滤波

figure;%figure3

B4=filter2(h3,I);

subplot(1,2,1);

imshow(B4,[ ]);

title(‘高斯低通滤波’);

h4=fspecial(‘laplacian’,0);%使用拉普拉斯滤波器

B5=filter2(h4,I);

subplot(1,2,2);

imshow(B5,[ ]);

title(‘拉普拉斯滤波器’);

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% %从空域的角度进行亮度变换

% %把灰度等级是10-100的变化到10-255

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

figure;%figure4

subplot(2,2,1);

imshow(I);

title(‘原始图像’);

J2=imadjust(I,[],[],0.5);% 增强低灰度级

subplot(2,2,2);

imshow(J2);

title(‘增强低灰度级’);

J3=imadjust(I,[ ],[ ],2);%增强高灰度级

subplot(2,2,3);

imshow(J3);

title(‘增强高灰度级’);

a1=100/255;%把灰度等级是10-100的变化到10-255

a2=255/255;

a3=10/255;

J2=imadjust(I,[a3,a1],[a3,a2],[]);

subplot(2,2,4);

imshow(J2);

title(‘把灰度等级是10-100的变化到10-255’);

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% %从频域的角度进行亮度变换

% %fft2

% %由于能量主要集中在低频部分

% %所以对低频进行处理可以得到理想的效果

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

I=imread(‘eight.tif’);

up=0.5;%设置处理频率上限

down=0.09%%设置处理频率下限

figure;%figure5

subplot(421);

imshow(I);

title(‘原始图像’);

f=double(I);

subplot(4,2,3);

imshow(log(abs(f)),[]);

title(‘unit8转化为double’);

g=fft2(f);

g=fftshift(g);

subplot(4,2,5);

imshow(log(abs(g)),[]);

title(‘FFT2变化后的图像’);

[M,N]=size(g);% 转换数据矩阵

y1=max(max(abs(g)));%求出最大频率

y2=min(min(abs(g)));%%求出最小频率

y3=(y1-y2)*up+y2;%设置滤波上限

y4=(y1-y2)*down+y2;%%设置滤波下限

for i=1:M

for j=1:N

if (abs(g(i,j))