JavaCV实现人脸检测功能

本文实例为大家分享了JavaCV实现人脸检测功能的具体代码，供大家参考，具体内容如下

/*
 * 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:
 *
 * <?xml version="1.0" encoding="utf-8"?>
 * <manifest xmlns:android="http://schemas.android.com/apk/res/android"
 *   package="com.googlecode.javacv.facepreview"
 *   android:versionCode="1"
 *   android:versionName="1.0" >
 *   <uses-sdk android:minSdkVersion="4" />
 *   <uses-permission android:name="android.permission.CAMERA" />
 *   <uses-feature android:name="android.hardware.camera" />
 *   <application android:label="@string/app_name">
 *     <activity
 *       android:name="FacePreview"
 *       android:label="@string/app_name"
 *       android:screenOrientation="landscape">
 *       <intent-filter>
 *         <action android:name="android.intent.action.MAIN" />
 *         <category android:name="android.intent.category.LAUNCHER" />
 *       </intent-filter>
 *     </activity>
 *   </application>
 * </manifest>
 */ 

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 < imageHeight; y++) {
      int dataLine = y*dataStride;
      int imageLine = y*imageStride;
      for (int x = 0; x < imageWidth; x++) {
        imageBuffer.put(imageLine + x, data[dataLine + f*x]);
      }
    }
    IplImage grayImageT = IplImage.create(height/f, width/f, IPL_DEPTH_8U, 1);
    //cvSaveImage("/storage/emulated/0/Pictures/grayImage.jpg",grayImage);
    cvTranspose(grayImage,grayImageT);
    //cvSaveImage("/storage/emulated/0/Pictures/grayImageT.jpg",grayImageT);
    cvFlip(grayImageT,grayImageT,0);
    //cvSaveImage("/storage/emulated/0/Pictures/grayImageT_X.jpg",grayImageT);
    cvFlip(grayImageT,grayImageT,1);
    //cvSaveImage("/storage/emulated/0/Pictures/grayImageT_Y.jpg",grayImageT); 

    cvClearMemStorage(storage);
    faces = cvHaarDetectObjects(grayImageT, classifier, storage, 1.1, 3, CV_HAAR_DO_CANNY_PRUNING);
    postInvalidate();
  } 

  @Override
  protected void onDraw(Canvas canvas) {
    Paint paint = new Paint();
    paint.setColor(Color.RED);
    paint.setTextSize(20); 

    String s = "FacePreview - This side up.";
    float textWidth = paint.measureText(s);
    canvas.drawText(s, (getWidth()-textWidth)/2, 20, paint); 

    if (faces != null) {
      paint.setStrokeWidth(2);
      paint.setStyle(Paint.Style.STROKE);
      float scaleX = (float)getWidth()/grayImage.width();
      float scaleY = (float)getHeight()/grayImage.height();
      int total = faces.total();
      for (int i = 0; i < total; i++) {
        CvRect r = new CvRect(cvGetSeqElem(faces, i));
        int x = r.x(), y = r.y(), w = r.width(), h = r.height();
        canvas.drawRect(x*scaleX, y*scaleY, (x+w)*scaleX, (y+h)*scaleY, paint);
      }
    }
    else{
      canvas.drawText("meiyoujiancedao", (getWidth()-textWidth)/2, 20, paint);
    }
  }
} 

// ---------------------------------------------------------------------- 

class Preview extends SurfaceView implements SurfaceHolder.Callback {
  SurfaceHolder mHolder;
  Camera mCamera;
  Camera.PreviewCallback previewCallback; 

  Preview(Context context, Camera.PreviewCallback previewCallback) {
    super(context);
    this.previewCallback = previewCallback; 

    // Install a SurfaceHolder.Callback so we get notified when the
    // underlying surface is created and destroyed.
    mHolder = getHolder();
    mHolder.addCallback(this);
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
  } 

  public void surfaceCreated(SurfaceHolder holder) {
    // The Surface has been created, acquire the camera and tell it where
    // to draw.
    mCamera = Camera.open(Camera.CameraInfo.CAMERA_FACING_FRONT);
    try {
      mCamera.setPreviewDisplay(holder);
    } catch (IOException exception) {
      mCamera.release();
      mCamera = null;
      // TODO: add more exception handling logic here
    }
  } 

  public void surfaceDestroyed(SurfaceHolder holder) {
    // Surface will be destroyed when we return, so stop the preview.
    // Because the CameraDevice object is not a shared resource, it's very
    // important to release it when the activity is paused.
    mCamera.stopPreview();
    mCamera.release();
    mCamera = null;
  } 

  private Size getOptimalPreviewSize(List<Size> 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) < minDiff) {
        optimalSize = size;
        minDiff = Math.abs(size.height - targetHeight);
      }
    } 

    // Cannot find the one match the aspect ratio, ignore the requirement
    if (optimalSize == null) {
      minDiff = Double.MAX_VALUE;
      for (Size size : sizes) {
        if (Math.abs(size.height - targetHeight) < minDiff) {
          optimalSize = size;
          minDiff = Math.abs(size.height - targetHeight);
        }
      }
    }
    return optimalSize;
  } 

  public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
    // Now that the size is known, set up the camera parameters and begin
    // the preview.
    Camera.Parameters parameters = mCamera.getParameters(); 

    List<Size> 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();
  } 

} 

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。

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