Point Grey Camera RAW capturer

Does anyone know how to capture RAW image from point grey camera (Grasshopper3) on “Video Device In Op”?

I want to change demosaic algorithm. In SpinView app, there are Color-Processing Methods. It seems
Touchdesinger use Nearest Neighbour(Fast) in “Video Device In OP”. Now I want to use Weighted Directional Filter.
My understanding, I need to write demosaic shader code by my self but before that I want to get RAW image from point gray camera.

If there is SDK that I can change, it would be very helpful.