Is possible to tap on object and detect it?

Hi everyone,
I'm building a simple scene (2017.3b) where I detect (with Vuforia) an ImageTarget showing a basic object.
Is it possible to detect if I tap the object on the screen?
If I show two objects, is possible to understand which one I tapped?

Thanks

 

You should be able to detect when you tap an object on the screen by using a raycast.

 

Yes, I should ...
but the raycast is conditioned on the Input.touchCount and it is always 0.

// Update is called once per frame
void Update () {

int i = 0;
while (i < Input.touchCount) {
if (Input.GetTouch(i).phase == TouchPhase.Began) {
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
....