trackers will lose their targets eventually, right now, it is impossible to reinitialize them with a fresh bbox.

there is a hidden isInit flag in the Tracker class, which is only reset once, in the constructor of the resp. implementation class, so repeated calls to init() won't have any effect currently.

thus each time a tracker loses the target, a new instance has to be created, somewhat undesirable, expensive.

@kurnianggoro , maybe you have an explanation, why this is so ?
(it seems deliberate, but i can't find any reason why)

shouldn't a miss in the update() function reset this ?