Load Dataset from path cause camera unstable

Hello,

First of all, I apologize for my bad English.

I have made an AR app, want it load dataset from persistentDataPath. It looks good at first. dataset has been load, imagetargets has create. But if attach something to imagetargets, it will be enable,but nothing can display before camera, because ARcamera is flying around scene, and imagetargets not follow it.

Here is my code, someone can help me? Thanks!

//Load function

public void LoadRecog()     {

DataSetHandle.LoadDataSetFromPath(Application.persistentDataPath+@"/Vuforia/basketball.xml");                 DataSetHandle.ConfigVideoTrackable("2", VideoPlane);  

}

//DataSetHandle.cs

public static void LoadDataSetFromPath(string absolutePath)     {         ObjectTracker objectTracker = TrackerManager.Instance.GetTracker<ObjectTracker>();         if (!DataSet.Exists(absolutePath, VuforiaUnity.StorageType.STORAGE_ABSOLUTE))         {             Debug.Log("load dataset Exists null");             return;         }         else         {             objectTracker.Stop();             dataSet = objectTracker.CreateDataSet();             if (dataSet.Load(absolutePath, VuforiaUnity.StorageType.STORAGE_ABSOLUTE))             {                 objectTracker.ActivateDataSet(dataSet);             }             objectTracker.Start();         }     }