how to apply 8x8 window to image of size 720x1280?

Hi, I have an image of size 720x1280. I need to apply the sliding window and block processing (neighborhood)operations to the image. the 8x8 window should be applied. Can you suggest anything

Answer 1

[Image Analyst]

See my attached demo. In one of them I compute standard deviations of the blocks. Adapt it to change the block sizes to whatever you want.

[ramya]

Thank you sir! I am sending you code related to this. I am getting the last output as scrambled. Kindly suggest something where the mistake is?

clc;  % Clear command window.
clear;  % Delete all variables.
close all;  % Close all figure windows except those created by imtool.

a=VideoReader('test.mp4');
b = read(a,1);
c=rgb2gray(b);
nframe=a.NumberOfFrames
tic
for i=115:116
  d =read(a,i-1);
  e=rgb2gray(d);
  figure
  imshow(e);
  pause(0.2)
  g =read(a,i);
  h=rgb2gray(g);
  figure
  imshow(h);
  rows = 8;
  columns = 8;
  [H,W,~] = size(c);
  szH = [repmat(fix(H/rows),1,rows)];
  szW = [repmat(fix(W/columns),1,columns)];
  
  C = mat2cell(e, szH, szW)';
  D =mat2cell(h, szH, szW)';
  figure, imshow(e)
  figure
  
  imshow(h);
  figure
  
  G=cell2mat(C);
  H=cell2mat(D);
  
  for i=1:rows*columns
    subplot(rows,columns,i), imshow( C{i} )
    
  end
  figure
  for i=1:rows*columns
    
    subplot(rows,columns,i), imshow( D{i} )
  end
  w=std(double(G));
  
  figure
  plot(w);
  b=std(double(H));
  
  figure
  plot(b);
  level = graythresh(G)
  
  level1 = graythresh(H)
  if level>level1
    T=im2bw(G)
    
    figure
    imshow(T);
  else
    
    P=im2bw(H);
    figure
    imshow(P);
    
  end
  
end

msgbox ('Done');

[Image Analyst]

You forgot to attach test1.mp4. Zip it up if you have to.

[ramya]

here is the video i am using for code.please suggest where i am going wrong in this?.

[Image Analyst]

preeti, I'm getting the last image as this:

Explain how that is scrambled, and what you expect it to look like. Keep in mind that I can't build a turnkey self-driving car application for you. So be short, and specific.

[ramya]

ohkay sir i will explain what exactly i want my last output to look like.i will explain this with help of the attached file.plz see to that.... my 3rd and 4th image are first two images then i have converted these 2 images into window size of 8 shown in 5th and 6th ,plotted standard deviation ,found graythresh. .based on graythresh level whichever is greater i have to plot one from 2 images i have taken.i am getting 9th image as my output where as i should get exactly like 2nd image..blocks have changed position.hope i have explained properly.

Answer 2

[Jos (10584)]

help blockproc

(if you have the Image Processing Toolbox)

[ramya]

thank u,but i have used mat2cell i have got the results.but i am not able to find standard deviation between two frames.suggest some code related to this?