JavaCV实现人脸检测功能

/* 
 * Copyright (C) 2010,2011,2012 Samuel Audet 
 * 
 * FacePreview - A fusion of OpenCV's facedetect and Android's CameraPreview samples, 
 *        with JavaCV + JavaCPP as the glue in between. 
 * 
 * This file was based on CameraPreview.java that came with the Samples for 
 * Android SDK API 8, revision 1 and contained the following copyright notice: 
 * 
 * Copyright (C) 2007 The Android Open Source Project 
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0 
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License. 
 * 
 * 
 * IMPORTANT - Make sure the AndroidManifest.xml file looks like this: 
 * 
 * <&＃63;xml version="1.0" encoding="utf-8"&＃63;> 
 *  
 *    
 *    
 *    
 *    
 *      
 *        
 *          
 *          
 *        
 *      
 *    
 *  
 */ 
 
package com.googlecode.javacv.facepreview; 
 
import android.app.Activity; 
import android.app.AlertDialog; 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.ImageFormat; 
import android.graphics.Paint; 
import android.hardware.Camera; 
import android.hardware.Camera.Size; 
import android.os.Bundle; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 
import android.view.View; 
import android.view.Window; 
import android.view.WindowManager; 
import android.widget.FrameLayout; 
import java.io.File; 
import java.io.IOException; 
import java.nio.ByteBuffer; 
import java.util.List; 
import com.googlecode.javacpp.Loader; 
import com.googlecode.javacv.cpp.opencv_objdetect; 
 
import static com.googlecode.javacv.cpp.opencv_core.*; 
import static com.googlecode.javacv.cpp.opencv_imgproc.*; 
import static com.googlecode.javacv.cpp.opencv_objdetect.*; 
import static com.googlecode.javacv.cpp.opencv_highgui.*; 
 
// ---------------------------------------------------------------------- 
 
public class FacePreview extends Activity { 
  private FrameLayout layout; 
  private FaceView faceView; 
  private Preview mPreview; 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    // Hide the window title. 
    requestWindowFeature(Window.FEATURE_NO_TITLE); 
 
    super.onCreate(savedInstanceState); 
 
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN); 
 
    // Create our Preview view and set it as the content of our activity. 
    try { 
      layout = new FrameLayout(this); 
      faceView = new FaceView(this); 
      mPreview = new Preview(this, faceView); 
      layout.addView(mPreview); 
      layout.addView(faceView); 
      setContentView(layout); 
    } catch (IOException e) { 
      e.printStackTrace(); 
      new AlertDialog.Builder(this).setMessage(e.getMessage()).create().show(); 
    } 
  } 
} 
 
// ---------------------------------------------------------------------- 
 
class FaceView extends View implements Camera.PreviewCallback { 
  public static final int SUBSAMPLING_FACTOR = 4; 
 
  private IplImage grayImage; 
  private CvHaarClassifierCascade classifier; 
  private CvMemStorage storage; 
  private CvSeq faces; 
 
  public FaceView(FacePreview context) throws IOException { 
    super(context); 
 
    // Load the classifier file from Java resources. 
    File classifierFile = Loader.extractResource(getClass(), 
      "/com/googlecode/javacv/facepreview/haarcascade_frontalface_alt2.xml", 
      context.getCacheDir(), "classifier", ".xml"); 
    if (classifierFile == null || classifierFile.length() <= 0) { 
      throw new IOException("Could not extract the classifier file from Java resource."); 
    } 
 
    // Preload the opencv_objdetect module to work around a known bug. 
    Loader.load(opencv_objdetect.class); 
    classifier = new CvHaarClassifierCascade(cvLoad(classifierFile.getAbsolutePath())); 
    classifierFile.delete(); 
    if (classifier.isNull()) { 
      throw new IOException("Could not load the classifier file."); 
    } 
    storage = CvMemStorage.create(); 
  } 
 
  public void onPreviewFrame(final byte[] data, final Camera camera) { 
    try { 
      Camera.Size size = camera.getParameters().getPreviewSize(); 
      processImage(data, size.width, size.height); 
      camera.addCallbackBuffer(data); 
    } catch (RuntimeException e) { 
      // The camera has probably just been released, ignore. 
    } 
  } 
 
  protected void processImage(byte[] data, int width, int height) { 
    // First, downsample our image and convert it into a grayscale IplImage 
    int f = SUBSAMPLING_FACTOR; 
    if (grayImage == null || grayImage.width() != width/f || grayImage.height() != height/f) { 
      grayImage = IplImage.create(width/f, height/f, IPL_DEPTH_8U, 1); 
    } 
    int imageWidth = grayImage.width(); 
    int imageHeight = grayImage.height(); 
    int dataStride = f*width; 
    int imageStride = grayImage.widthStep(); 
    ByteBuffer imageBuffer = grayImage.getByteBuffer(); 
    for (int y = 0; y  sizes, int w, int h) { 
    final double ASPECT_TOLERANCE = 0.05; 
    double targetRatio = (double) w / h; 
    if (sizes == null) return null; 
 
    Size optimalSize = null; 
    double minDiff = Double.MAX_VALUE; 
 
    int targetHeight = h; 
 
    // Try to find an size match aspect ratio and size 
    for (Size size : sizes) { 
      double ratio = (double) size.width / size.height; 
      if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue; 
      if (Math.abs(size.height - targetHeight)  sizes = parameters.getSupportedPreviewSizes(); 
    Size optimalSize = getOptimalPreviewSize(sizes, w, h); 
    parameters.setPreviewSize(optimalSize.width, optimalSize.height); 
 
    mCamera.setParameters(parameters); 
    if (previewCallback != null) { 
      mCamera.setPreviewCallbackWithBuffer(previewCallback); 
      Camera.Size size = parameters.getPreviewSize(); 
      byte[] data = new byte[size.width*size.height* 
          ImageFormat.getBitsPerPixel(parameters.getPreviewFormat())/8]; 
      mCamera.addCallbackBuffer(data); 
    } 
    mCamera.startPreview(); 
  } 
 
}