I've read its possible to use the built in android face detector to find the position of faces in a bitmap. Does anyone know of any examples of doing this using the camera as an input?
Its possible with the Face Detection APIs in ICS. Refer the camera section on this page: http://developer.android.com/sdk/android-4.0.html
You must register a
FaceDetectionListener and then call
camera.startFaceDetection(). Please read the link above for more details.
I wrote some sample code. It isn't perfect since its Work In Progress but the face detection bit works just fine: