MOTION TRACKING – PROBLEM 1

Since absorbing myself into the world of Maya I have increasingly felt the urge to return to video in the hope of incorporating live action and 3D. I had originally stated in my proposal that this would come at a later stage in the course but I’m feeling now that compositing will play a greater role in my work on simulation. The software I’m using to composite is Shake which is a node based 2D vfx program; Apple’s version of After Effects. However I came across a problem quite early on that put me back a couple of frustrating weeks.

I’ve been filming with a Canon HG10 CMOS video camera for a couple of months with the intention of importing the footage into a motion tracking program called PFtrack. However over the past couple of weeks it has been impossible for me to get a decent track out of this program. I tried alternative methods such as manually tracking in the Live section of Maya that has given similar results. The other day I came across a blog detailing certain problems that CMOS cameras have when matchmoving. It appears the senors on these cameras use a different form of image making to record through the use of a rolling shutter. Any handheld or panning movement of the camera creates a distortion that literally stretches, bends and wobbles the video footage. This is generally unnoticeable in playback but when tracking points in PFtrack, the software pinpoints individual pixels to calibrate the movement of the camera which if distorted cause huge problems when exported to Maya. Here is a useful website that explains the difference between CCD and CMOS cameras;

http://dvxuser.com/jason/CMOS-CCD/

For now it seems I can only composite effectively if the camera is positioned on a tripod. This is not a problem for the time being however I would like to use handheld video in the future.

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