MATLAB: Drawing a bounding box around foreground objects

Question

Hello Everyone.

I have applied a backgrund subtraction algorithm called frame differencing it is working very well I can easily detect the moving objects from the video now I want to draw the rectanlge or bounding boc around the detected objects.I have used the connected component labelling here like that below provided by Image Analyst.But I could not draw the bounding box..Any help is appreciated.

figure(3);imshow(fg1);

drawnow;

hold on;

labeledImage = bwconncomp(fg1,8);

measurements = regionprops(labeledImage,'BoundingBox','Centroid');

if length(measurements) == 0

% No blobs found.

fprintf('Done!\n');

continue; % Skip to the next frame.

end

totalNumberOfBlobs = length(measurements);

for blobNumber = 1:totalNumberOfBlobs

bb = measurements(blobNumber).BoundingBox;

bco = measurements(blobNumber).Centroid;

rectangle('Position',bb,'EdgeColor','r','LineWidth',2)

plot(bco(1),bco(2),'-m+')

myCaption = sprintf('(x=%.1f, y=%.1f)', bco(1), bco(2));

text(bco(1)+15,bco(2), myCaption,…

'FontName','Arial','FontWeight','normal',…

'FontSize',12,'Color','blue');

set(gca,'xdir','normal')

set(gca,'ydir','reverse')

axis on;

end

drawnow; % Force display to update.

fprintf('Done!\n');

end

end

hold off

toc

uiwait(msgbox('Execution Ended'));

Answer 1

You probably need a "hold on" between these two lines:

rectangle('Position',bb,'EdgeColor','r','LineWidth',2)
plot(bco(1),bco(2),'-m+')

Like this:

rectangle('Position',bb,'EdgeColor','r','LineWidth',2)
hold on;
plot(bco(1),bco(2),'-m+')