Object tracking not reliable

[Lgfv32]

I'm using vision assistant express and it manages to track it in it but once I run my entire vi sometimes the bounding box tracks it on the side of the object or sometimes it tracks other thing that are not the object I want to track. My question is how can I make it more efficient so the bounding box stays in the object and doesn't loses it and tracks right 

[Hatef.fouladi]

there is many item that are important in this problem
but first you have to introduce the method that you use for tracking