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- What are the tracking parameters and what are there units?
Question The documentation doesnt have a hint as to what they are or how to best manipulate them. I'm trying different numbers atm. I would like a few good streaks that link across lots of images.
inside TRACK.PAR
I'm assuming the dv's are changes in position you want the software to track, with 0.8 tracking close pixel changes, and 80 allowing the particle to move farther away. Dangle - I'm not sure, but 60 gave me the picture and when I go to 100deg I get only a handfull of links. Dacc - im not sure, but maybe its changes in acceleration between points? below 1 i get only a few points.
dvxmin
dvxmax
dvymin
dvymax
dvzmin
dvzmax
dangle
dacc
Answer
From Dominik Bauer (detailed documentation on www.openptv.net) report:
OpenPTV uses a spatio-temporal tracking algorithm which is described in (Maas 1993) and (Willneff 2003). As input, this algorithm needs eight parameters. These include the minimum and maximum displacement in each coordinate direction, the angle a particle in direction along its trajectory and a magnitude acceleration. Since these parameters constitute the general boundary conditions of the particle velocities, it is important to have an approximate idea what velocities to expect.
dv* are in pixels/frame IIRC,
dangle in gradians (400 gradians in a circle)
dacc in pixels/frame^2