How can I change the pixel origin in 640x480 pixel value?

Its look likes the new origin located in 320x240 pixel center of 640x480 pixel. I want to run the real time video and want make the new origin need in the center of that 640x480.

[Guillaume]

You'll have to give a lot more context to your question to get an answer. Possibly, this is something to do with the image acquisition toolbox.

Basic images are just matrices. They don't have a concept of origin.