Video processing using VCAPG2 MATLAB

Question

Hi; any suggestion about of how can I use the VCAPG2.dll in background or segmentation processing?, thanks for your help.

I'm using the follow code (from an example by de author), for processing in real time, I was trying to convert in binary image, I hope you can help me.

clear all;  
cardnum=vcapg2; % you will get available video capture devices number usually 1  
close all;figure(1);set(1,'doublebuffer','on');  
% capture mode  
for i=1:100  
aa=vcapg2;% grabbing camera image.  
subplot(2,1,1);imshow(aa);subplot(2,1,2);imshow(diff(double(aa(:,:,1)),[]));  
drawnow;% this is important to view realtime.  
end  
clear all; % remove