How do you calculate the "offset" and "scales" on cityflow?

[SasinPhimsiri]

Can you describe step by step on cityflow_s01 and cityflow_s02? Thank you :)

[regob]

Hi @SasinPhimsiri,

Those cameras have overlaps, so I took one reference camera (which will be scale 1), and I picked a vehicle in the beginning of the video and one at the end, and checked the elapsed time in seconds. Now if we do the same on other cameras, and:

• the time elapsed on the reference camera is $t_1$
• same event took $t_2$ on the second camera
• then the scale of camera 2 is $t_2 / t_1$

I calculated the offsets similarly, by picking the appearance of the same vehicle in the beginning of the video (say $t_1$ on the reference. and at $t_2$ on the other camera), then the offset is $t_1 - t_2$.

If the cameras don't have overlaps, it's more difficult I guess. Probably one can do it by picking a few vehicles and checking the differences in their transition times. (which is needed anyway for configuring the transition windows)