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武林网。