Detecting multiple images in a single image

Question

I need help to identify the border and compare the images with the original image. I need guidance on How can I achieve this through processing or matlab or anything for beginne

Answer 1

You can use correlation method to position the multiple images:

file1='http://i.stack.imgur.com/1KyJA.jpg';
file2='http://i.stack.imgur.com/zyHuj.jpg';
It = imread(file1);
Ii = imread(file2);
It=rgb2gray(It);
Ii=rgb2gray(Ii);
It=double(It);  % template
Ii=double(Ii);  % image

Ii_mean = conv2(Ii,ones(size(It))./numel(It),'same');
It_mean = mean(It(:));
corr_1 = conv2(Ii,rot90(It-It_mean,2),'same')./numel(It);
corr_2 = Ii_mean.*sum(It(:)-It_mean);
conv_std = sqrt(conv2(Ii.^2,ones(size(It))./numel(It),'same')-Ii_mean.^2);
It_std = std(It(:));
S = (corr_1-corr_2)./(conv_std.*It_std);

imagesc(abs(S))

The result will give you the positions with maximum values:

Get the coordinates of maxima, and position your template centroid at the same position, check the difference between your template and the matching image.

I am not sure what do you mean by "identify the border", but you can always extract the edges with canny detector:

bw=edge(It);
bw=imfill(bw,'holes');
figure,imshow(bw)