how can i get a bounding box for the detected blob in a video

hi, am intrested in knowing how to get a bounding box for the detected blob in a video my code involves background subraction & i use simple functions

clc

clear all

close all

m=0; n=0;

readerobj = mmreader('dt2.wmv');% dt2 is my sample fixed cam video

vidframes = read(readerobj);

thresh = 15;

bg = read(readerobj,1);

bg_bw = double(rgb2gray(bg));

fr_size = size(vidframes);

width = fr_size(2);

height = fr_size(1);

fg = zeros(height, width);

numFrames=get(readerobj,'NumberofFrames');

for k = 1 : numFrames

mov(k).cdata = vidframes(:,:,:,k);

mov(k).colormap = [];

end

movie(mov, 1, readerobj.FrameRate)

a=1; x=[0 0]; p=0; c=0; for i = 2:2:numFrames

    fr = read(readerobj,i); 
    fr_bw = rgb2gray(fr);       

    fr_diff = abs(double(fr_bw) - double(bg_bw));  

    for j=1:width                 
         for k=1:height

             if ((fr_diff(k,j) > thresh))
                 fg(k,j) = 255; %fr_bw(k,j)
             else
                 fg(k,j) = 0;
             end

             if (fr_bw(k,j) > bg_bw(k,j))          
               bg_bw(k,j) = bg_bw(k,j) + 1;           
             elseif (fr_bw(k,j) < bg_bw(k,j))
               bg_bw(k,j) = bg_bw(k,j) - 1;     
             end

         end    
    end

       %median filter to remove noise
    L=medfilt2(fg,[5,5]);            
    %removing small parts less than threshold area
    final=bwareaopen(L,4000);               

    %filling the holes
    ifill=imfill(final,'holes');          
    %to know the number of connected objects
    [Ilabel num]=bwlabel(ifill);          
    if (num>=1)
    %region properties of the image
    Iprops=regionprops(Ilabel);            
    %extracting the bounding box properties
    Ibox=[Iprops.BoundingBox]; 
????

after this i want a code which would continuously draw a bounding box arounf the blob?

[Image Analyst]

Read this and please fix: http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup

Answer 1

[Image Analyst]

Try starting with something like this:

delete hRect; % Delete prior boxes.
for blobIndex = 1 : num
  thisBB = Iprops(blobIndex).BoundingBox;
  hRect(blobIndex) = rectangle('Position', thisBB);
end

You will have to initialize hRect the first time (to anything at all) so the delete doesn't bomb.

[Cedric]

Hi Image Analyst,

Thank you for the WB in this thread (I answered there).

[Image Analyst]

You're welcome Cedric. I saw that, even though I didn't reply. I'm trying to remember to vote for your posts to get your privileges up.

[Cedric]

I just saw that I got a push from you, thank you!