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《数字图像处理原理与实践（MATLAB版）》一书之代码Part5

2024-08-08 09:15:21   220人阅读

《数字图像处理原理与实践（MATLAB版）》一书之代码Part5

本文系《数字图像处理原理与实践（MATLAB版）》一书之代码系列的Part5，辑录该书第225至第280页之代码（此处应部分读者之需求调整了代码发布的顺序——详细说明请见下面的文章链接），供有需要读者下载研究使用。代码执行结果请参见原书配图，建议下载代码前阅读下文：

关于《数字图像处理原理与实践（MATLAB版）》一书代码发布的说明

http://blog.csdn.net/baimafujinji/article/details/40987807

P245

I = imread(‘lena.png‘);
fcoef=fft2(double(I));            %FFT变换
tmp1 =log(1+abs(fcoef));
spectrum = fftshift(fcoef);        %调整中心
tmp2 = log(1+abs(spectrum));
ifcoef = ifft2(fcoef);            %逆变换

figure                            %显示处理结果
subplot(2,2,1), imshow(I), title(‘source image‘);
subplot(2,2,2), imshow(tmp1,[]), title(‘FFT image‘);
subplot(2,2,3), imshow(tmp2,[]), title(‘shift FFT image‘);
subplot(2,2,4), imshow(ifcoef,[]), title(‘IFFT image‘);

P251

J= double(imread(‘lena.bmp‘));
K = dct2(J);
figure, imshow(K,[0 255])

P252-1

J= double(imread(‘lena.bmp‘));
K = dct2(J);
figure, imshow(K,[0 255]);
K_i = idct2(K);
figure, imshow(K_i,[0 255])

P252-2

J= double(imread(‘lena.bmp‘));
A = J(1:8,1:8);
D = dctmtx(8);
dct_1 = D*A;
dct_2 = D‘*dct_1;

P252-3

J= double(imread(‘lena.bmp‘));
A = J(1:8,1:8);
D = dctmtx(8);
dct_1 = D*A*D‘;
dct_2 = dct2(A);

P253

I = imread(‘cameraman.tif‘);
I = im2double(I);
T = dctmtx(8);
dct = @(block_struct) T * block_struct.data * T‘;
B = blockproc(I,[8 8],dct);
mask = [1   1   1   1   0   0   0   0
        1   1   1   0   0   0   0   0
        1   1   0   0   0   0   0   0
        1   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0];
B2 = blockproc(B,[8 8],@(block_struct) mask .* block_struct.data);
invdct = @(block_struct) T‘ * block_struct.data * T;
I2 = blockproc(B2,[8 8],invdct);
imshow(I), figure, imshow(I2)

P262

a = [0 0 1 1 0 0 1 1];
b = fwht(a);

P263

I = imread(‘baboon.bmp‘);
I1 = double(I);
T = hadamard(8);
myFun1 = @(block_struct)T*block_struct.data*T/64;
H = blockproc(I1, [8 8], myFun1);
H(abs(H)<3.5)=0;
myFun2 = @(block_struct)T*block_struct.data*T;
I2 = blockproc(H, [8 8], myFun2);
subplot(121), imshow(I1,[]), title(‘original image‘);
subplot(122), imshow(I2,[]), title(‘zipped image‘);

P264

I = imread(‘baboon.bmp‘);
I1 = double(I);
[m n] =size(I);
sizi = 8;
num = 16;
%分块进行离散沃尔什变换
T = hadamard(sizi);
myFun1 = @(block_struct)T*block_struct.data*T/(sizi.^2);
hdcoe = blockproc(I1, [sizi, sizi], myFun1);
%重新排列系数
coe = im2col(hdcoe,  [sizi, sizi], ‘distinct‘);
coe_t = abs(coe);
[Y, ind] = sort(coe_t);
%舍去绝对值较小的系数
[m_c, n_c] = size(coe);
for i = 1:n_c
coe(ind(1:num, i), i)=0;
end
%重建图像
re_hdcoe = col2im(coe, [sizi, sizi], [m, n], ‘distinct‘);
myFun2 = @(block_struct)T*block_struct.data*T;
re_s = blockproc(re_hdcoe, [sizi, sizi], myFun2);
subplot(121), imshow(I1,[]), title(‘original image‘);
subplot(122), imshow(re_s,[]), title(‘compressed image‘);

P268

dim1 = [1 1 1 2 2 2 3 3 3];
dim2 = [1 2 3 1 2 3 1 2 3];
dim3 = [63 75 78 50 56 65 70 71 80];

sum( (dim1-mean(dim1)) .* (dim2-mean(dim2)) ) / ( 9-1 ) % 0
sum( (dim1-mean(dim1)) .* (dim3-mean(dim3)) ) / ( 9-1 ) % 0.625
sum( (dim2-mean(dim2)) .* (dim3-mean(dim3)) ) / (9-1 ) % 5

std(dim1)^2  %  0.75
std(dim2)^2  %  0.75
std(dim3)^2  %  100.7778

P274

X = [2 2; 2 3; 3 4; 4 3; 5 4; 5 5];
[COEFF,SCORE,latent,tsquare] = princomp(X);

P275-1

X0=X-repmat(mean(X),6,1);
SCORE_1 = X0*COEFF;

P275-2

X = [2 2; 2 3; 3 4; 4 3; 5 4; 5 5];
V = cov(X);
[COEFF,latent] = pcacov(V)

P277

I = imread(‘baboon.bmp‘);
x = double(I)/255;
[m,n]=size(x);
y =[];
%拆解图像
for i = 1:m/8;
    for j = 1:n/8;
        ii = (i-1)*8+1;
        jj = (j-1)*8+1;
        y_app = reshape(x(ii:ii+7,jj:jj+7),1,64);
        y=[y;y_app];
    end
end

%KL变换
[COEFF,SCORE,latent] = princomp(y);
kl = y * COEFF;

kl1 = kl;
kl2 = kl;
kl3 = kl;

%置零压缩过程
kl1(:, 33:64)=0;
kl2(:, 17:64)=0;
kl3(:, 9:64)=0;

%KL逆变换
kl_i = kl*COEFF‘;
kl1_i = kl1*COEFF‘;
kl2_i = kl2*COEFF‘;
kl3_i = kl3*COEFF‘;

image = ones(256,256);
image1 = ones(256,256);
image2 = ones(256,256);
image3 = ones(256,256);

k=1;
%重组图像
for i = 1:m/8;
    for j = 1:n/8;

        y = reshape(kl_i(k, 1:64),8,8);
        y1 = reshape(kl1_i(k, 1:64),8,8);
        y2 = reshape(kl2_i(k, 1:64),8,8);
        y3 = reshape(kl3_i(k, 1:64),8,8);

        ii = (i-1)*8+1;
        jj = (j-1)*8+1;

        image(ii:ii+7,jj:jj+7) = y;
        image1(ii:ii+7,jj:jj+7) = y1;
        image2(ii:ii+7,jj:jj+7) = y2;
        image3(ii:ii+7,jj:jj+7) = y3;

        k=k+1;
    end
end

（代码发布未完，请待后续...）

《数字图像处理原理与实践（MATLAB版）》一书之代码Part5


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