Matlab图像处理任务.docx

Matlab图像处理任务目录Matlab图像处理任务1实验目的1实验内容1实验实现代码2主函数2zigzag变换2反zigzag变换3实验结果3实验结果分析5实验目的在matlab平台上，编码实现图像数据的读取、离散余弦变换、频域数据的控制和操作、重构图像等任务。实验内容用matlab软件编程实现下述任务：用imread函数读取一幅灰度图像I，对图像I进行分块，块的大小为8。利用dct2函数对每一个图像块进行离散余弦变换，然后对变换后的系数矩阵进行zig-zag扫描，得到一个大小为8*8的一位数组，对数组的后n个数置0，然后将新的数组进行反zig-zag变换，得到新的系数矩阵，最后利用idct2函数进行反离散余弦变换，得到新的图像块。对所有的图像块完成上述操作之后，得到新的重建图像。最后，用imwrite函数保存得到的新图像，或是用imshow函数画出该图像后保存。实验实现代码主函数Main.m:A = imread(G:LearningMultiMediaimageBoat.bmp,bmp); disp(A); m,n = size(A); B = zeros(m,n); s = 8; a = 1; k = 1; for i = 1:32 b = 1; for j = 1:32 tt = a, a + s - 1, b, b + s - 1; disp(tt); t1 = A(a:a+s-1,b:b+s-1); t2 = dct2(t1); t1 = zigzag(t2); t1(60:64),1) = 0; t2 = atzigzag(t1); t1 = idct2(t2)./255; B(a:a+s-1,b:b+s-1) = t1; b = b+s; end a = a+s; end imwrite(B,change.bmp,bmp); subplot(1,2,1),imshow(A) subplot(1,2,2),imshow(B)zigzag变换function back = zigzag(example)back = zeros(64,1);seq = 0,1,8,16,9,2,3,10, . 17,24,32,25,18,11,4,5, . 12,19,26,33,40,48,41,34, . 27,20,13,6,7,14,21,28, . 35,42,49,56,57,50,43,36, . 29,22,15,23,30,37,44,51, . 58,59,52,45,38,31,39,46, . 53,60,61,54,47,55,62,63; seq = seq + 1; a = zeros(64,1); for count = 1:8 a(count - 1)*8 + 1:count*8) = example(:,count); end for count = 1:64 back(seq(count) = a(count); end反zigzag变换 function back = atzigzag(example) back = zeros(8,8); seq = 0,1,8,16,9,2,3,10, . 17,24,32,25,18,11,4,5, . 12,19,26,33,40,48,41,34, . 27,20,13,6,7,14,21,28, . 35,42,49,56,57,50,43,36, . 29,22,15,23,30,37,44,51, . 58,59,52,45,38,31,39,46, . 53,60,61,54,47,55,62,63; seq = seq + 1; middle = zeros(64,1); for count = 1:64 middle(count) = example(seq(count); end for count = 1:8 back(:,count) = middle(count - 1)*8 + 1:count*8); end实验结果（采取了控制置零的个数来比较实验效果）n = 10n = 20n = 30 n = 40 n = 50 n = 60实验结果分析随着置零数目的提高，经过zig-zag变换和反zig-zag变换系列操作之后的图像的清晰度会有所提高。置零个数越多，图像压缩处理的程度就越大，但