how to update image preview every frame?

Hi,

I am trying to use the Image Acquisition Toolbox to view a video stream as it comes in. I want to process the image as it comes in, however. Setting the 'UpdatePreviewWindowFcn' works, but it only applies the processing to a few frames. The processing isn't too complicates, all I want to do is display the transpose of he image, and a plot of the integrated brightness along the x-axis and y-axis in 2 different subplots. Something like:

finaldata=event.Data;

finaldata=transpose(finaldata(:,:,1));

% Display image data(only first color level)

set(himage, 'CData', finaldata)

int_fr=sum((finaldata(:,:)));

int_fr2=sum(finaldata(:,:),2);

subplot(2,2,2)

plot(int_fr);

subplot(2,2,4)

plot(int_fr2);

(this is what I put in the preview function)

Is there any way to make sure this function is called every time I display a frame? Note: The image acquisition doesn't need to be too fast, so if I could just not display the frames for which this isn't being called, that would work too.

Thanks for any help, -d

Answer 1

[bethel o]

I have not used the Image aquisition toolbox before. But can you not just put thus in the so called preview function just to test before doing anything complex.

finaldata=event.Data;
imshow(finalData(:,:,1),[])% require image processing toolbox, or you can just
%use image(), but your image aquisition toolbox shouls have somthing that can 
%display image
drawnow

Answer 2

[bethel o]

what about the function 'drawnow'? See link

http://www.mathworks.co.uk/help/techdoc/ref/drawnow.html

[Dylan]

Hmmm... doesn't seem to have any effect if I place it inside the 'UpdatePreviewWindowFcn'. Is that what you had in mind?