I'm trying to use the google vision api facetracker sample ( https://github.com/googlesamples/android-vision/tree/master/visionSamples/FaceTracker ) to detect and track faces without showing the preview (at least detect, tracking is not necessary).
The main problem is that if I delete the "preview" I don't receive the callback in "onNewItem(int faceId, Face item)" (function in FaceTrackerActivity in the github link provided).
I've been lookin through SO and I didn't find anything similar to this question, also it's not necessary that I use "google vision api", if you know another system that can achieve this objective it's perfect.
Thanks for reading.