Trajectory tracking from a detector output .txt file

A trajectory file is produced from a detector file which which contains trajectories.

The files written out by the detection process are used as input for the tracker to infer trajectories of each object. The tracker needs to deal with different scenarios, including merging silhouettes of people. Also, it has to cope with imperfect detections. The trajectories constructed contain sequences of position coordinates of a particular object together with times at which the coordinates were sampled:
{(x1,y1, time1), (x2,y2, time2), ..., (xN,yN, timeN)}