Yes it is possible, but it is not natively supported. Therefore, the way through ImageCapture will not work here. Nevertheless, no one prevents you to use a library like opencv to access the webcam. With a MathLink wrapper you can write a routine to catch frames from the cam and transfer them as Image to Mathematica.
When opencv is initialized and has opened your cam, the pure catching routine is in the simplest case very short:
void catchFrame(void){
if(!frame){
MLPutSymbol(stdlink,"$Failed");
return;
}
long dims[3],size,mu;
int *bm;
dims[0]=frame->height;
dims[1]=frame->width;
dims[2]=frame->nChannels;
size=dims[0]*dims[1];
mu=size*dims[2];
bm=new int[mu];
for(long i=0; i<size; i++) {
bm[3*i]=(unsigned char)frame->imageData[3*i+2];
bm[3*i+1]=(unsigned char)frame->imageData[3*i+1];
bm[3*i+2]=(unsigned char)frame->imageData[3*i];
}
MLPutFunction(stdlink,"Image",2);
MLPutIntegerArray(stdlink,bm,dims,NULL,3);
MLPutString(stdlink,"Byte");
delete[] bm;
}
I admit that this approach is not as simple as calling ImageCapture, but if you are willing to install opencv and cweb I could send you an implementation. It was once written by Jens-Peer Kuska and I only made it work for Mathematica 8.0 and its Image-framework.
Update
I made a pure C version (without CWeb) and added a detailed how-to-use comment. You can download the file from here and with a bit of luck you can use images from your webcam in a few minutes.
