How to crop out the object from the image and then store the objects in the image?

I able to detect centroid of each objects in the image, and I require to crop out each objects from the image THEN to store it in different variable.How to crop the objects and store it in different variable?? I need coding... thanks

Answer 1

[Anton Semechko]

Assuming you have Image Processing Toolbox you can try the code below. You can also easily modify it to suit your needs.

% Get the image
im=imread('http://i43.tinypic.com/2w1tlwh.jpg');
im=rgb2gray(im); % convert to gray scale
im=im>graythresh(im)*255; % covert to binary
siz=size(im); % image dimensions

% Label the disconnected foreground regions (using 8 conned neighbourhood)
L=bwlabel(im,8);

% Get the bounding box around each object
bb=regionprops(L,'BoundingBox');

% Crop the individual objects and store them in a cell
n=max(L(:)); % number of objects
ObjCell=cell(n,1);
for i=1:n

      % Get the bb of the i-th object and offest by 2 pixels in all
      % directions
      bb_i=ceil(bb(i).BoundingBox);
      idx_x=[bb_i(1)-2 bb_i(1)+bb_i(3)+2];
      idx_y=[bb_i(2)-2 bb_i(2)+bb_i(4)+2];
      if idx_x(1)<1, idx_x(1)=1; end
      if idx_y(1)<1, idx_y(1)=1; end
      if idx_x(2)>siz(2), idx_x(2)=siz(2); end
      if idx_y(2)>siz(1), idx_y(2)=siz(1); end

      % Crop the object and write to ObjCell
      im=L==i;
      ObjCell{i}=im(idx_y(1):idx_y(2),idx_x(1):idx_x(2));

end

% Visualize the individual objects
figure
for i=1:n
    subplot(1,n,i)
    imshow(ObjCell{i})
end
clear im L bb n i bb_i idx_x idx_y siz

[lingru celine]

@Anton Semechko

thank you...this code very useful for me :)

i get the image as below shown:

<<http://i40.tinypic.com/bivx1x.jpg>>;

By the way, i want to know how to do the image matching for this image ?? My project is about to detect the this bus number, so now i need to do the matching... (ps: Take the other object inside the image match with the number"70") may i know how to do it ?? thank you

i need the coding ..

[lingru celine]

what's the meaning of " if idx_x(1)<1, idx_x(1)=1; end

if idx_y(1)<1, idx_y(1)=1; end

if idx_x(2)>siz(2), idx_x(2)=siz(2); end

if idx_y(2)>siz(1), idx_y(2)=siz(1); end" ?

[Anton Semechko]

To detect object with know appearance and geometry, you can try template matching. There are a bunch of examples of this on FEX. Here is one of them: http://www.mathworks.com/matlabcentral/fileexchange/20061-template-matching

[lingru celine]

thanks. i go that website and the matching output is what i want,but there don't have any template match coding for me to refer..i really need this, can i have the coding for matching? thanks

[lingru celine]

@Anton Semechko

I could not understand,what's the meaning of

" if idx_x(1)<1, idx_x(1)=1; end

if idx_y(1)<1, idx_y(1)=1; end

if idx_x(2)>siz(2), idx_x(2)=siz(2); end

if idx_y(2)>siz(1), idx_y(2)=siz(1); end" ?

can explain for me ?

[Anurag]

The code works just fine. But I am concerned about the noise around the man. Why there are so many dots around it. Help me remove it please.

Answer 2

[Image Analyst]

I do cropping of objects to separate variables (images) in my BlobsDemo image segmentation tutuorial http://www.mathworks.com/matlabcentral/fileexchange/25157-blobsdemo

[lingru celine]

thanks ,, quite useful for me