均值滤波
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2022-05-21 13:48:41
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噪声原理
1.高斯噪声是指它的概率密度函数服从高斯分布(即正态分布)的一类噪声。
2.椒盐噪声,椒盐噪声又称脉冲噪声,它随机改变一些像素值,是由图像传感器,传输信道,解码处理等产生的黑白相间的亮暗点噪声。椒盐噪声往往由图像切割引起。
滤波原理
均值滤波是一种线性滤波器,将一个窗口区域中的像素计算平均值,然后将窗口中计算得到的均值设置为锚点上的像素值。均值滤波用卷积实现,得到的像素值需除以窗口尺寸大小。此次实验中的卷积模板如下:
滤波结果
原图:
滤波结果:
每个滤波结果对应于该图正上方所加噪声
代码
%Write by 长安 Rjex
clc ,clear all;
I = imread('myImage.jpg');
A = rgb2gray(I);
J = imnoise(A,'gaussian',0,0.02); %加高斯噪声
J1 = imnoise(A,'gaussian',0,0.04);
J2 = imnoise(A,'gaussian',0,0.06);
J3 = imnoise(A,'salt & pepper',0.2); %加椒盐噪声
J4 = imnoise(A,'salt & pepper',0.4);
J5 = imnoise(A,'salt & pepper',0.6);
C = double(J);
C1 = double(J1);
C2 = double(J2);
C3 = double(J3);
C4 = double(J4);
C5 = double(J5);
N = 3; %确定均值滤波模板
flag = (N-1)/2;
for i = flag+1:size(J,1)-flag
for j = flag+1:size(J,2)-flag
C(i,j)=sum(sum(J(i-flag:i+flag,j-flag:j+flag)/(N*N)));
end
end
C = uint8(C);
N1 = 3; %确定均值滤波模板
flag = (N1-1)/2;
for i = flag+1:size(J1,1)-flag
for j = flag+1:size(J1,2)-flag
C1(i,j)=sum(sum(J1(i-flag:i+flag,j-flag:j+flag)/(N1*N1)));
end
end
C1 = uint8(C1);
N2 = 3; %确定均值滤波模板
flag = (N2-1)/2;
for i = flag+1:size(J2,1)-flag
for j = flag+1:size(J2,2)-flag
C2(i,j)=sum(sum(J2(i-flag:i+flag,j-flag:j+flag)/(N2*N2)));
end
end
C2 = uint8(C2);
N3 = 3; %确定均值滤波模板
flag = (N3-1)/2;
for i = flag+1:size(J3,1)-flag
for j = flag+1:size(J3,2)-flag
C3(i,j)=sum(sum(J3(i-flag:i+flag,j-flag:j+flag)/(N3*N3)));
end
end
C3 = uint8(C3);
N4 = 3; %确定均值滤波模板
flag = (N4-1)/2;
for i = flag+1:size(J4,1)-flag
for j = flag+1:size(J4,2)-flag
C4(i,j)=sum(sum(J4(i-flag:i+flag,j-flag:j+flag)/(N4*N4)));
end
end
C4 = uint8(C4);
N5 = 3; %确定均值滤波模板
flag = (N5-1)/2;
for i = flag+1:size(J5,1)-flag
for j = flag+1:size(J5,2)-flag
C5(i,j)=sum(sum(J5(i-flag:i+flag,j-flag:j+flag)/(N5*N5)));
end
end
C5 = uint8(C5);
figure(1);
imshow(A),title('原图像');
figure(2);
subplot(2,3,1),imshow(J),title('a.加高斯噪声(0,0.02)');
subplot(2,3,4),imshow(C),title('b.均值滤波3*3');
subplot(2,3,2),imshow(J1),title('c.加高斯噪声(0,0.04)');
subplot(2,3,5),imshow(C1),title('d.均值滤波3*3');
subplot(2,3,3),imshow(J2),title('e.加高斯噪声(0,0.06)');
subplot(2,3,6),imshow(C2),title('f.均值滤波3*3'); figure(3);
subplot(2,3,1),imshow(J3),title('a.加椒盐噪声(0.02)');
subplot(2,3,4),imshow(C3),title('b.均值滤波3*3');
subplot(2,3,2),imshow(J4),title('c.加椒盐噪声(0.04)');
subplot(2,3,5),imshow(C4),title('d.均值滤波3*3');
subplot(2,3,3),imshow(J5),title('e.加椒盐噪声(0.06)');
subplot(2,3,6),imshow(C5),title('f.均值滤波3*3');
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