数字图像处理-数字图像基础

• 用matlab程序实现同时对比度实验。

clear
m=256;
n=256;
ground_gray1=180;
X1=ones(m,n)*ground_gray1;
ground_gray2=120;
X2=ones(m,n)*ground_gray2;
before_gray=150;
m0=100;
n0=100;
step=50;
X1(m0:m0+step,n0:n0+step)=before_gray;
subplot(1,2,1);
imshow(uint8(X1));
title('before150,ground180');
X2(m0:m0+step,n0:n0+step)=before_gray;
subplot(1,2,2);
imshow(uint8(X2));
title('before150,ground120');

• 用matlab程序实验空间分辨率变化效果

clear
X1=imread('lena.jpg');
subplot(1,3,1);
imshow(uint8(X1));
title('180*180');
[m,n]=size(X1);
hold on;

X2=X1(1:2:m,1:2:n);
subplot(1,3,2);
imshow(uint8(X2));
title('90*90');
hold on;

X3=X1(1:3:m,1:3:n);
subplot(1,3,3);
imshow(uint8(X3));
title('60*60');
hole on;

• 用matlab程序实验幅度分辨率变化效果

clear
X=imread('lena.jpg');
[m,n]=size(X);
figure
subplot(1,3,1);
imshow(uint8(X));
title('180级');

for i=1:m
    for j=1:n
        X2(i,j)=2*(ceil(X(i,j)/2)); %仅保留2的倍数的灰度值
    end
end

subplot(1,3,2);
imshow(uint8(X2));
title('90级');


for i=1:m
    for j=1:n
        X3(i,j)=3*(ceil(X(i,j)/3)); %仅保留3的倍数的灰度值
    end
end

subplot(1,3,3);
imshow(uint8(X3));
title('60级');