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Face Detection M-D v1
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.Gms.Vision.Faces;
using Android.Gms.Vision;
using VisionSample;
namespace FaceRec
{
[Activity(Label = "FaceRec", MainLauncher = true, Icon = "@drawable/icon")]
public class MainActivity : Activity
{
const string TAG = "FaceTracker";
CameraSource mCameraSource;
CameraSourcePreview mPreview;
GraphicOverlay mGraphicOverlay;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
SetContentView(Resource.Layout.Main);
mPreview = FindViewById<CameraSourcePreview>(Resource.Id.preview);
mGraphicOverlay = FindViewById<GraphicOverlay>(Resource.Id.faceOverlay);
var detector = new FaceDetector.Builder(Application.Context).Build();
detector.SetProcessor(
new MultiProcessor.Builder(new GraphicFaceTrackerFactory(mGraphicOverlay)).Build());
if (!detector.IsOperational)
{
// Note: The first time that an app using face API is installed on a device, GMS will
// download a native library to the device in order to do detection. Usually this
// completes before the app is run for the first time. But if that download has not yet
// completed, then the above call will not detect any faces.
//
// isOperational() can be used to check if the required native library is currently
// available. The detector will automatically become operational once the library
// download completes on device.
Android.Util.Log.Warn(TAG, "Face detector dependencies are not yet available.");
}
mCameraSource = new CameraSource.Builder(Application.Context, detector)
.SetRequestedPreviewSize(640, 480)
.SetFacing(CameraFacing.Back)
.SetRequestedFps(30.0f)
.Build();
}
protected override void OnResume()
{
base.OnResume();
StartCameraSource();
}
protected override void OnPause()
{
base.OnPause();
mPreview.Stop();
}
protected override void OnDestroy()
{
mCameraSource.Release();
base.OnDestroy();
}
//==============================================================================================
// Camera Source Preview
//==============================================================================================
/**
* Starts or restarts the camera source, if it exists. If the camera source doesn't exist yet
* (e.g., because onResume was called before the camera source was created), this will be called
* again when the camera source is created.
*/
void StartCameraSource()
{
try
{
mPreview.Start(mCameraSource, mGraphicOverlay);
}
catch (Exception e)
{
Android.Util.Log.Error(TAG, "Unable to start camera source.", e);
mCameraSource.Release();
mCameraSource = null;
}
}
//==============================================================================================
// Graphic Face Tracker
//==============================================================================================
/**
* Factory for creating a face tracker to be associated with a new face. The multiprocessor
* uses this factory to create face trackers as needed -- one for each individual.
*/
class GraphicFaceTrackerFactory : Java.Lang.Object, MultiProcessor.IFactory
{
public GraphicFaceTrackerFactory(GraphicOverlay overlay) : base()
{
Overlay = overlay;
}
public GraphicOverlay Overlay { get; private set; }
public Android.Gms.Vision.Tracker Create(Java.Lang.Object item)
{
return new GraphicFaceTracker(Overlay);
}
}
/**
* Face tracker for each detected individual. This maintains a face graphic within the app's
* associated face overlay.
*/
class GraphicFaceTracker : Tracker
{
GraphicOverlay mOverlay;
FaceGraphic mFaceGraphic;
public GraphicFaceTracker(GraphicOverlay overlay)
{
mOverlay = overlay;
mFaceGraphic = new FaceGraphic(overlay);
}
/**
* Start tracking the detected face instance within the face overlay.
*/
public override void OnNewItem(int idValue, Java.Lang.Object item)
{
mFaceGraphic.Id = idValue;
}
/**
* Update the position/characteristics of the face within the overlay.
*/
public override void OnUpdate(Detector.Detections detections, Java.Lang.Object item)
{
mOverlay.Add(mFaceGraphic);
mFaceGraphic.UpdateFace(item.JavaCast<Face>());
}
/**
* Hide the graphic when the corresponding face was not detected. This can happen for
* intermediate frames temporarily (e.g., if the face was momentarily blocked from
* view).
*/
public override void OnMissing(Detector.Detections detections)
{
mOverlay.Remove(mFaceGraphic);
}
/**
* Called when the face is assumed to be gone for good. Remove the graphic annotation from
* the overlay.
*/
public override void OnDone()
{
mOverlay.Remove(mFaceGraphic);
}
}
}
}
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