How can I count one matrix in big another matrix ?

Hi guys I'm trying to writing program to classified many images (hand writing alphabet for arabic font like 'ا' ) so i decided to convert them into binary images then I used one function to get Skeleton of the font. after that I figured out I can count the edge of alphabet with this algorithm for example We have

A=[ 0 0 0 0 0 ;
    0 0 1 0 0 ;
    0 0 1 0 0 ;
    0 0 1 0 0 ;
    0 0 0 0 0 ]

I have to find out how many

B=[ 0 0 0; 
    0 1 0;
    0 1 0 ]

And

C=[ 0 1 0;
    0 1 0;
    0 0 0 ]

available in A matrix ?

output must return 2 for this example, so the edges are 2

Are there any functions in matlab to do this ?

Thank You for your helping ...

Answer 1

[Matt Fig]

There may be something in the IPT that does this, or you can try this FEX file out:

FINDSUBMAT

A=[0 0 0 0 0;0 0 1 0 0;0 0 1 0 0;0 0 1 0 0;0 0 0 0 0];
B=[0 0 0;0 1 0;0 1 0];
C=[0 1 0;0 1 0;0 0 0];
findsubmat(A,B)  % Returns index of location of B in A.
length(findsubmat(A,C)) % Returns num of Cs in A.

[Sean de Wolski]

I think this is kind of what bwhitmiss does. Though I would probably just use conv2 and some logical conditions:

sum(conv2(A,B,'same')==sum(B(:)))

[Walter Roberson]

Hamid writes "thank's bro it worked ..."

Answer 2

[Image Analyst]

Sean's solution will do what you asked, but you might want to look into normxcorr2() which would do a better job of finding the whole character. In fact it might even do a better job if you don't convert to binary. Okay, you're probably wondering how you can use this strange new function. Well, I have a demo for that (like dozens of other things). Here it is:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
imtool close all;  % Close all imtool figures.
clear;  % Erase all existing variables.
workspace;  % Make sure the workspace panel is showing.
format longg;
format compact;
fontSize = 20;

% Check that user has the Image Processing Toolbox installed.
hasIPT = license('test', 'image_toolbox');
if ~hasIPT
  % User does not have the toolbox installed.
  message = sprintf('Sorry, but you do not seem to have the Image Processing Toolbox.\nDo you want to try to continue anyway?');
  reply = questdlg(message, 'Toolbox missing', 'Yes', 'No', 'Yes');
  if strcmpi(reply, 'No')
    % User said No, so exit.
    return;
  end
end

% Read in a standard MATLAB color demo image.
folder = fullfile(matlabroot, '\toolbox\images\imdemos');
baseFileName = 'peppers.png';
% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);
if ~exist(fullFileName, 'file')
  % Didn't find it there.  Check the search path for it.
  fullFileName = baseFileName; % No path this time.
  if ~exist(fullFileName, 'file')
    % Still didn't find it.  Alert user.
    errorMessage = sprintf('Error: %s does not exist.', fullFileName);
    uiwait(warndlg(errorMessage));
    return;
  end
end
rgbImage = imread(fullFileName);
% Get the dimensions of the image.  numberOfColorBands should be = 3.
[rows columns numberOfColorBands] = size(rgbImage);
% Display the original color image.
subplot(2, 2, 1);
imshow(rgbImage, []);
axis on;
title('Original Color Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);

smallSubImage = imcrop(rgbImage, [192 82 60 52]);
subplot(2, 2, 2);
imshow(smallSubImage, []);
axis on;
title('Template Image to Search For', 'FontSize', fontSize);

% Search the red channel for a match.
correlationOutput = normxcorr2(smallSubImage(:,:,1), rgbImage(:,:,1));
subplot(2, 2, 3);
imshow(correlationOutput, []);
title('Correlation Output', 'FontSize', fontSize);

[maxCorrValue, maxIndex] = max(abs(correlationOutput(:)));
[ypeak, xpeak] = ind2sub(size(correlationOutput),maxIndex(1));
corr_offset = [(xpeak-size(smallSubImage,2)) (ypeak-size(smallSubImage,1))];

subplot(2, 2, 4);
imshow(rgbImage);
hold on;
rectangle('position',[corr_offset(1) corr_offset(2) 50 50],...
          'edgecolor','g','linewidth',2);
title('Template Image Found in Original Image', 'FontSize', fontSize);