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i dont get an output for this using a GUI and a toggle button. Whats wrong?

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clc;
source= videoinput('winvideo');
set(source, 'ReturnedColorSpace', 'RGB');
set(source, 'FramesPerTrigger', 1);
set(source, 'TriggerRepeat', inf);
triggerconfig(source, 'manual');
if get(handles.startstop,'Value')
start(source);
thresh = 15/255;
pause(2);
trigger(source);
bg = getdata(source,1,'double');
bg=bg(:,:,:,1);
bg_bw = rgb2gray(bg);
set(handles.startstop,'String','Stop');
set(handles.startstop,'Value',1);
handles.source = source;
guidata(gcbo, handles);
drawnow();
fr_size = size(bg);
width = fr_size(2);
height = fr_size(1);
f = zeros(height, width);
else
set(handles.startstop,'String','Start');
set(handles.startstop,'Value',0);
source = handles.source;
stop(source);
handles.source = [];
guidata(gcbo, handles)
end
while(get(handles.startstop,'Value'));
trigger(source);
fr = getdata(source,3,'double');
fr1=fr(:,:,:,1);
fr_bw1 = rgb2gray(fr1);
trigger(source);
fr2=fr(:,:,:,2);
fr_bw2 = rgb2gray(fr2);
trigger(source);
fr3=fr(:,:,:,3); % read in frame-i+1
fr_bw3 = rgb2gray(fr3); % convert frame-i+1 to grayscale
fr_diff1 = abs((fr_bw1) - (fr_bw2)); % First frame Difference cast operands as double to avoid negative overflow
fr_diff2 = abs((fr_bw2) - (fr_bw3)); % Second frame difference cast operands as double to avoid negative overflow
for j=1:width % if fr_diff > thresh pixel in foreground
for k=1:height
if ((fr_diff1(k,j) > thresh) && (fr_diff2(k,j) > thresh))
f(k,j) = 255;
else
f(k,j) = 0;
end
end
end
subplot(1,2,1); imshow(fr1); title('REAL TIME VIDEO');
subplot(1,2,2); imshow(uint8(f)); title('DETECTED MOVING OBJECT'); bg_bw=fr_bw1;
end

Answers (1)

Jan
Jan on 31 Jan 2013
Please explain the occurring problem with any detail: Do you get an infinite loop, an error message, is the code too slow or does the figure disappear before you can see it?
The debugger can help you to find out, what happens: Set a breakpoint in the code and step through the program line by line.
Btw., you can omit the double FOR loop:
f = 255 * ((fr_diff1 > thresh) & (fr_diff2 > thresh));
  6 Comments
Sanjeev
Sanjeev on 31 Jan 2013
here is the simplified version of my code
clc;
source = videoinput('winvideo');
set(source, 'ReturnedColorSpace', 'RGB');
set(source, 'FramesPerTrigger', 3);
set(source, 'TriggerRepeat', 50);
triggerconfig(source, 'manual');
start(source);
thresh = 15/255;
trigger(source);
bg = getdata(source,1,'double');
bg=bg(:,:,:,1);
bg_bw = rgb2gray(bg); % convert background to greyscale
% ----------------------- set frame size variables -----------------------
fr_size = size(bg);
width = fr_size(2);
height = fr_size(1);
f = zeros(height, width);
for i=1:50
trigger(source);
fr = getdata(source,3,'double');
fr1=fr(:,:,:,1);
fr_bw1 = rgb2gray(fr1);
trigger(source);
fr2=fr(:,:,:,2);
fr_bw2 = rgb2gray(fr2);
trigger(source);
fr3=fr(:,:,:,3); % read in frame-i+1
fr_bw3 = rgb2gray(fr3); % convert frame-i+1 to grayscale
fr_diff1 = abs((fr_bw1) - (fr_bw2)); % First frame Difference cast operands as double to avoid negative overflow
fr_diff2 = abs((fr_bw2) - (fr_bw3)); % Second frame difference
cast operands as double to avoid negative overflow
f = 255 * ((fr_diff1 > thresh) & (fr_diff2 > thresh));
figure(1),subplot(2,1,1),imshow(fr1)
subplot(2,1,2),imshow(uint8(f))
end
stop(source); delete(source); clear (source);
Image Analyst
Image Analyst on 31 Jan 2013
Don't double space all your code after you paste it in. That is not necessary to get it to show up with one line of code per statement. Simply make sure there is a blank line before it, then highlight it all and click {}Code.

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