如何将图像划分为重叠块

Question

我需要使用matlab将一张512*512的图像划分为41*41的重叠。换句话说，我想先取一个以q为中心的41*41块，然后移动一个像素，再取一个以q+1为中心的41*41块，以此类推。我不能使用Blockproc，因为它给出了一个不重叠的块。

thanks to help me

Answer 1

你可以使用BLOCKPROC。这有点不明显。

设置块大小为[11]，然后使用'Border'参数指定每个像素周围的块大小:

>> a
a =
     8     1     6
     3     5     7
     4     9     2
>> blockproc(a, [1 1], @(bs)disp(bs.data),'BorderSize', [1 1 ])
     0     0     0
     0     8     1
     0     3     5
     0     0     0
     1     6     0
     5     7     0
     0     3     5
     0     4     9
     0     0     0
     5     7     0
     9     2     0
     0     0     0
     0     0     0
     8     1     6
     3     5     7
     0     8     1
     0     3     5
     0     4     9
     8     1     6
     3     5     7
     4     9     2
     3     5     7
     4     9     2
     0     0     0
     1     6     0
     5     7     0
     9     2     0

Answer 2

用

循环

block_size = 41;
row_startpos = 1;
col_startpos = 1;
Img = imread('your_image.jpg');
>Loop Begins here
a = Img(row_startpos:block_size,col_startpos:block_size);
row_startpos = row_startpos+row_overlap;
col_startpos = col_startpos+col_overlap;
>Loop Ends here

添加边框检查条件等

Answer 3

获得重叠块的最简单方法是使用带有'滑动'选项的im2col()。

%Read images one at a time , get overlapping patches of size sz,sz and concatenate it to      columns of a matrix.
% LOOP HERE
f=imread([inp_dir files(k).name]);
   % extract patches of image
   P=[P im2col(f,[sz sz],'sliding')];
% END LOOP HERE

Answer 4

首先声明一个变量(Var)来存储blocksize为41*41的图像块。然后使用两个for循环提取图像的块。代码如下:

I = imread('cameraman.tif');
[row,col] = size(I);
window = 41;
Var = zeros(1:window,1:window);
 for i = 21:row-window
     for j= 21:col-window
         Var = I(i-20:i+20,j-20:j+20);
     end;
 end;`