canot convert image to movie frame using 'im2frame'

here the code :

//

vObj = vision.VideoFileReader(car_video.avi);

while ~isDone(vObj)
     v = step(vObj);

       if (v > threshold)
            a=a+1;
            imshow (v);
            f(a) = im2frame(v);
       end

end
movie(f,10);

//

and i get error message like this 'Error using im2frame Can only make movie frames from image matrices of type double or uint8'

Answer 1

[Geoff Hayes]

Fitroh - according to the documentation at vision.VideoFileReader and step, the output of the step function is a frame, so the im2frame function should be unnecessary. Verify the class type of v by putting a breakpoint at the line

 f(a) = im2frame(v);

and then run the program. When the debugger pauses at this line, type the following in the Command Window

 class(v)

Based on the output of this call, if the class type is struct then it is (probably) a frame with the fields cdata and colormap. If that is the case, then you can replace your above line with just

 f(a) = v;

Try the above and see what happens!

Answer 2

[Image Analyst]

What is f? Is it a struct? It must be to use get frame() output. See attached demo.