I want to change the reference axis of an object relative to the camera of another object

I am making an application to cardboard , the problem is that I want to rotate an object in relation to the movement of the head of the person, both up and down. I made using the physics worked out using your finger , going good , but when it is for the cardboard does not work, the rotation does not go as expected. The object is camera the child being of cardboard , so it will always stay in front of the camera , further rotate it , you must change the reference axes , for the camera and the object must be the same to be done that How do I change the reference axis of the object to be the same as the cardboard camera?

Here is the piece of code that works with your finger:

   if(Input.touchCount>lastTouchcount)
     {
         LastState = Input.GetMouseButton(0);
         LastPos = Input.mousePosition;
     }
   lastTouchcount = Input.touchCount;
   if(Input.GetMouseButton(0)==true
    #if UNITY_IOS || UINITY_ANDROID
         && Input.touchCount==1
      #endif
     )
     {
         Vector3 v = Input.mousePosition-LastPos;
         float tmp=v.x;
         v.x=v.y;
         v.y=-tmp;
         GetComponent<Rigidbody>().AddTorque(v);
     }

     LastState = Input.GetMouseButton(0);
     LastPos = Input.mousePosition;

Here is the code for the cardboard where the rotation does not go as expected:

    if (EyeConfig.Instance.Render == EyeConfig.RenderType.CardBoard) 
     {
         var head = FindObjectOfType<CardboardHead> ();

         Vector3 delta = lastPosCam - head.transform.rotation.eulerAngles;

         float temp = delta.x;
         delta.x = delta.y;
         delta.y = temp;

         GetComponent<Rigidbody>().AddTorque(delta * 2000);
         lastPosCam = head.transform.rotation.eulerAngles;
     }