public static bool isFoundTracker;

    // Position the camera relative to a Trackable.
    private void PositionCamera(TrackableBehaviour trackableBehaviour,
                                  Camera arCamera,
                                  QCARManagerImpl.PoseData camToTargetPose)
    {
        if(isFoundTracker)
        {
            arCamera.transform.localPosition = trackableBehaviour.transform.rotation *
                                                            Quaternion.AngleAxis(90, Vector3.left) *
                                                            Quaternion.Inverse(camToTargetPose.orientation) *
                                                            (-camToTargetPose.position) +
                                                            trackableBehaviour.transform.position;

            arCamera.transform.rotation = trackableBehaviour.transform.rotation *
                                                          Quaternion.AngleAxis(90, Vector3.left) *
                                                          Quaternion.Inverse(camToTargetPose.orientation);
            isFoundTracker = false;
            Debug.Log("== SET POSE");
        }
        else
        {
            arCamera.transform.localPosition = Vector3.Lerp(arCamera.transform.localPosition,
                                                            trackableBehaviour.transform.rotation *
                                                            Quaternion.AngleAxis(90, Vector3.left) *
                                                            Quaternion.Inverse(camToTargetPose.orientation) *
                                                            (-camToTargetPose.position) +
                                                            trackableBehaviour.transform.position, QCARBehaviour.LerpCoef);

            arCamera.transform.rotation = Quaternion.Lerp( arCamera.transform.rotation,
                                                          trackableBehaviour.transform.rotation *
                                                          Quaternion.AngleAxis(90, Vector3.left) *
                                                          Quaternion.Inverse(camToTargetPose.orientation), QCARBehaviour.LerpCoef);
        }


    }