David Tarkowski

i am using matlab version 7.5 ,i got this error when i run your code, is ter anything thing i ned to type to run it?
??? Error using ==> imaqmotion at 55
IMAQMOTION is unable to run properly.
Input argument "obj" is undefined

Thank you for this great demo! It worked just out-of-the-box! However, stepping through your code I've noticed some things which could be optimized:

1. Checking for the input arguments (line 30f) will fail if you try to pass an invalid videoinput object, e.g. one being deleted by delete(obj) but which is still in your workspace. In my opinion it would be better to rewrite the error-condition as follows:

elseif ( (nargin == 1) && (~isa(obj, 'imaqdevice') || ~isvalid(obj)) )
% error handling
end

2. It worked better for me to use imshow instead of imscale function updating the image axes (line 311) since imshow seems to preserve the aspect ratio.

3. It might be a good idea to convert YCbCr color space to RGB before displaying it in line 311. This way the red line indicating the selected video line will remain red (without conversion its green) and the image will look naturally. I just put

data = ycbcr2rgb(data);

into the switch-statement beginning in line 276 into the 'ycbcr' case. Alternatively you can put this conversion into the switch-statement beginning in the line 239 or even reduce this two switch-statements into one since they both switching the same parameter. I didn't try this, but it should work.

However these are just small things without great impact on the functionality. So I'd like to thank you again for this clean and well documented demo!

can some one help me debug this error..

Warning: File 'log.txt' not found.
> In motion_detection>togglebutton1_Callback at 96
  In gui_mainfcn at 75
  In motion_detection at 42
Warning: File 'film.avi' not found.
> In motion_detection>togglebutton1_Callback at 97
  In gui_mainfcn at 75
  In motion_detection at 42
Warning: File 'var.mat' not found.
> In motion_detection>togglebutton1_Callback at 98
  In gui_mainfcn at 75
  In motion_detection at 42

radio =

     1

??? Error using ==> videoinput.videoinput
There are no devices installed for the specified ADAPTORNAME. See IMAQHWINFO.

Error in ==> sad_algorithm at 17
vobj=videoinput('winvideo',2) %initializes a video object to connect to camera

Error in ==> motion_detection>togglebutton1_Callback at 101
    sad_algorithm

Error in ==> gui_mainfcn at 75
        feval(varargin{:});

Error in ==> motion_detection at 42
    gui_mainfcn(gui_State, varargin{:});

??? Error while evaluating uicontrol Callback.