Real Time PC communication

I'm developing some new image processing techniques that I'd like to apply in "real time".
For that I'd like a way to capture (preferably in Matlab) the images when the HDI5000 "print" botton is pressed.

The receiving PC has the following connections:
USB 2.0
VGA serial port
LAN
WLAN

I would very greatly appreciate any help or tips on this subject.

Best  regards,
David Afonso & José Seabra - Research at ICVL and IST, Portugal