使用Camera类调用摄像头获取每一帧数据

在这里先记录一下,有时间再整理

package com.yfmao.fras;


import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Date;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Point;
import android.graphics.Rect;
import android.graphics.YuvImage;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

import com.yfmao.mylibrary.faceid.FaceID;
import com.yfmao.mylibrary.jni.OneDetection;

import org.opencv.core.Mat;
import org.opencv.imgproc.Imgproc;

import static org.opencv.android.Utils.bitmapToMat;

public class camera_frame extends Activity implements SurfaceHolder.Callback,
        Camera.PreviewCallback {

    private SurfaceView mSurfaceview = null; // SurfaceView对象：(视图组件)视频显示
    private SurfaceHolder mSurfaceHolder = null; // SurfaceHolder对象：(抽象接口)SurfaceView支持类
    private Camera mCamera = null; // Camera对象，相机预览
    private Point mCameraSize;


    private int total_detect = 0;
    private float total_time = 0;
    private float ave_time = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera_frame);
        mSurfaceview = (SurfaceView) findViewById(R.id.surfaceView);
        mSurfaceHolder = mSurfaceview.getHolder(); // 绑定SurfaceView，取得SurfaceHolder对象
        mSurfaceHolder.addCallback(this); // SurfaceHolder加入回调接口
        mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);// 設置顯示器類型，setType必须设置
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        if (mCamera == null) {
            return;
        }
        mCamera.stopPreview();
        mCamera.setPreviewCallback(this);
        mCamera.startPreview();
    }

    @Override
    protected void onResume() {
        super.onResume();
        mCamera = Camera.open();
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (mCamera != null) {
            mCamera.release();
            mCamera = null;
        }
    }

    @Override
    protected void onStop(){
        super.onStop();
        mCamera.release();
        mCamera = null;
    }

    @Override
    protected void onDestroy(){
        super.onDestroy();
        mCamera.release();
        mCamera = null;
    }

    //释放Camera
    public void releaseCamera() {
        if (mCamera != null) {
            mCamera.setPreviewCallback(null);
            mCamera.stopPreview();// 停掉摄像头的预览
            mCamera.release();
            mCamera = null;
        }
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            if (mCamera != null) {
                mCamera.setPreviewDisplay(mSurfaceHolder);
                mCamera.startPreview();
                mCamera.autoFocus(null);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

    }



    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        releaseCamera();
    }

    @Override
    public void onPreviewFrame(byte[] data, Camera camera) {
        Camera.Parameters parameters = camera.getParameters();
        Size size = parameters.getPreviewSize();
        YuvImage image = new YuvImage(data, parameters.getPreviewFormat(), size.width, size.height,null);

        ByteArrayOutputStream out_image = new ByteArrayOutputStream();
        image.compressToJpeg(new Rect(0, 0, size.width, size.height), 100, out_image);
        byte[] bytes = out_image.toByteArray();
        Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);


        Mat rgba= new Mat();
        bitmapToMat(bitmap,rgba);

        Imgproc.cvtColor(rgba, rgba, Imgproc.COLOR_RGBA2BGR);

        Date a1 = new Date();
        OneDetection[] face_dets = FaceID.DetectFace(rgba.getNativeObjAddr());
        int maxidx = FaceID.GetMaxId();
        Date b1 = new Date();
        long interval1 = (b1.getTime() - a1.getTime());
        System.out.println("检测耗时：" + "    "+interval1+"ms");//会打印出相差3秒




        if(maxidx == 0) {
            String name[]=new String[1];
            float score[]=new float[1];
            int face_id[]= new int[1];


            Date a2 = new Date();
            int recog_result = FaceID.thenRecognize(face_dets[maxidx].getFaceBoxIdx(), face_id, name, score);
            Date b2 = new Date();
            long interval2 = (b2.getTime() - a2.getTime());
            System.out.println("识别时间　　："+interval2+"ms");//会打印出相差3秒

            long total = interval1 + interval2;
            System.out.println("检测+识别时间："+total+"ms");//会打印出相差3秒

            total_detect += 1;
            total_time += total;
            ave_time = total_time / total_detect;
            System.out.println("平均检测+识别时间：  " + ave_time + " ms");
        }

    }
}

其中, onPreviewFrame是对每一帧图像的具体处理.