实例介绍
【实例简介】
在安卓系统内实现车牌号自动识别
【实例截图】
【核心代码】
package com.aiseminar.platerecognizer.ui;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.ImageFormat;
import android.graphics.Rect;
import android.graphics.YuvImage;
import android.hardware.Camera;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.aiseminar.EasyPR.PlateRecognizer;
import com.aiseminar.platerecognizer.R;
import com.aiseminar.platerecognizer.base.BaseActivity;
import com.aiseminar.util.BitmapUtil;
import com.aiseminar.util.DateUtil;
import com.aiseminar.util.FileUtil;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Date;
import butterknife.Bind;
import butterknife.ButterKnife;
import butterknife.OnClick;
public class CameraActivity extends BaseActivity implements SurfaceHolder.Callback {
@Bind(R.id.svCamera)
SurfaceView mSvCamera;
@Bind(R.id.ivPlateRect)
ImageView mIvPlateRect;
@Bind(R.id.ivCapturePhoto)
ImageView mIvCapturePhoto;
@Bind(R.id.tvPlateResult)
TextView mTvPlateResult;
private static final String TAG = CameraActivity.class.getSimpleName();
private int cameraPosition = 0; // 0表示后置，1表示前置
private SurfaceHolder mSvHolder;
private Camera mCamera;
private Camera.CameraInfo mCameraInfo;
private MediaPlayer mShootMP;
private PlateRecognizer mPlateRecognizer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
ButterKnife.bind(this);
mPlateRecognizer = new PlateRecognizer(this);
initData();
}
@Override
public void onStart() {
super.onStart();
if (this.checkCameraHardware(this) && (mCamera == null)) {
// 打开camera
mCamera = getCamera();
// 设置camera方向
mCameraInfo = getCameraInfo(Camera.CameraInfo.CAMERA_FACING_BACK);
if (null != mCameraInfo) {
adjustCameraOrientation();
}
if (mSvHolder != null) {
setStartPreview(mCamera, mSvHolder);
}
}
}
@Override
public void onPause() {
super.onPause();
/**
* 记得释放camera，方便其他应用调用
*/
releaseCamera();
}
@Override
public void onDestroy() {
super.onDestroy();
}
/**
* 初始化相关data
*/
private void initData() {
// 获得句柄
mSvHolder = mSvCamera.getHolder(); // 获得句柄
// 添加回调
mSvHolder.addCallback(this);
}
private Camera getCamera() {
Camera camera = null;
try {
camera = Camera.open();
} catch (Exception e) {
// Camera is not available (in use or does not exist)
camera = null;
Log.e(TAG, "Camera is not available (in use or does not exist)");
}
return camera;
}
private Camera.CameraInfo getCameraInfo(int facing) {
int numberOfCameras = Camera.getNumberOfCameras();
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
for (int i = 0; i < numberOfCameras; i ) {
Camera.getCameraInfo(i, cameraInfo);
if (cameraInfo.facing == facing) {
return cameraInfo;
}
}
return null;
}
private void adjustCameraOrientation() { // 调整摄像头方向
if (null == mCameraInfo || null == mCamera) {
return;
}
int orientation = this.getWindowManager().getDefaultDisplay().getOrientation();
int degrees = 0;
switch (orientation) {
case Surface.ROTATION_0:
degrees = 0;
break;
case Surface.ROTATION_90:
degrees = 90;
break;
case Surface.ROTATION_180:
degrees = 180;
break;
case Surface.ROTATION_270:
degrees = 270;
break;
}
int result;
if (mCameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
result = (mCameraInfo.orientation degrees) % 360;
result = (360 - result) % 360; // compensate the mirror
} else {
// back-facing
result = (mCameraInfo.orientation - degrees 360) % 360;
}
mCamera.setDisplayOrientation(result);
}
/**
* 释放mCamera
*/
private void releaseCamera() {
if (mCamera != null) {
mCamera.setPreviewCallback(null);
mCamera.stopPreview();// 停掉原来摄像头的预览
mCamera.release();
mCamera = null;
}
}
@OnClick({R.id.ivCapturePhoto})
public void onClick(View view) {
switch (view.getId()) {
case 999: // R.id.id_switch_camera_btn:
// 切换前后摄像头
int cameraCount = 0;
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
cameraCount = Camera.getNumberOfCameras();// 得到摄像头的个数
for (int i = 0; i < cameraCount; i ) {
Camera.getCameraInfo(i, cameraInfo);// 得到每一个摄像头的信息
if (cameraPosition == 1) {
// 现在是后置，变更为前置
if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
/**
* 记得释放camera，方便其他应用调用
*/
releaseCamera();
// 打开当前选中的摄像头
mCamera = Camera.open(i);
// 通过surfaceview显示取景画面
setStartPreview(mCamera,mSvHolder);
cameraPosition = 0;
break;
}
} else {
// 现在是前置， 变更为后置
if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK) {
/**
* 记得释放camera，方便其他应用调用
*/
releaseCamera();
mCamera = Camera.open(i);
setStartPreview(mCamera,mSvHolder);
cameraPosition = 1;
break;
}
}
}
break;
case R.id.ivCapturePhoto:
// 拍照,设置相关参数
// Camera.Parameters params = mCamera.getParameters();
// params.setPictureFormat(ImageFormat.JPEG);
// DisplayMetrics metric = new DisplayMetrics();
// getWindowManager().getDefaultDisplay().getMetrics(metric);
// int width = metric.widthPixels; // 屏幕宽度（像素）
// int height = metric.heightPixels; // 屏幕高度（像素）
// params.setPreviewSize(width, height);
// // 自动对焦
// params.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
// mCamera.setParameters(params);
try {
mCamera.takePicture(shutterCallback, null, jpgPictureCallback);
} catch (Exception e) {
Log.d(TAG, e.getMessage());
}
break;
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
setStartPreview(mCamera, mSvHolder);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mSvHolder.getSurface() == null) {
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e) {
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
setStartPreview(mCamera, mSvHolder);
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// 当surfaceview关闭时，关闭预览并释放资源
/**
* 记得释放camera，方便其他应用调用
*/
releaseCamera();
holder = null;
mSvCamera = null;
}
/**
* TakePicture回调
*/
Camera.ShutterCallback shutterCallback = new Camera.ShutterCallback() {
public void onShutter() {
shootSound();
mCamera.setOneShotPreviewCallback(previewCallback);
}
};
Camera.PictureCallback rawPictureCallback = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
camera.startPreview();
}
};
Camera.PictureCallback jpgPictureCallback = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
camera.startPreview();
File pictureFile = FileUtil.getOutputMediaFile(FileUtil.FILE_TYPE_IMAGE);
if (pictureFile == null) {
Log.d(TAG, "Error creating media file, check storage permissions: ");
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
// 照片转方向
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
Bitmap normalBitmap = BitmapUtil.createRotateBitmap(bitmap);
// fos.write(data);
normalBitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
fos.close();
// 更新图库
// 把文件插入到系统图库
// try {
// MediaStore.Images.Media.insertImage(CameraActivity.this.getContentResolver(),
// pictureFile.getAbsolutePath(), pictureFile.getName(), "Photo taked by RoadParking.");
// } catch (FileNotFoundException e) {
// e.printStackTrace();
// }
// 最后通知图库更新
CameraActivity.this.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" pictureFile.getAbsolutePath())));
Toast.makeText(CameraActivity.this, "图像已保存。", Toast.LENGTH_SHORT).show();
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " e.getMessage());
}
}
};
/** Check if this device has a camera */
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
/**
* activity返回式返回拍照图片路径
* @param mediaFile
*/
private void returnResult(File mediaFile) {
// Intent intent = new Intent();
// intent.setData(Uri.fromFile(mediaFile));
// this.setResult(RESULT_OK, intent);
this.finish();
}
/**
* 设置camera显示取景画面,并预览
* @param camera
*/
private void setStartPreview(Camera camera,SurfaceHolder holder){
try {
camera.setPreviewDisplay(holder);
camera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error starting camera preview: " e.getMessage());
}
}
/**
* 播放系统拍照声音
*/
private void shootSound() {
AudioManager meng = (AudioManager) this.getSystemService(Context.AUDIO_SERVICE);
int volume = meng.getStreamVolume( AudioManager.STREAM_NOTIFICATION);
if (volume != 0) {
if (mShootMP == null)
mShootMP = MediaPlayer.create(this, Uri.parse("file:///system/media/audio/ui/camera_click.ogg"));
if (mShootMP != null)
mShootMP.start();
}
}
/**
* 获取Preview界面的截图，并存储
*/
Camera.PreviewCallback previewCallback = new Camera.PreviewCallback() {
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
// 获取Preview图片转为bitmap并旋转
Camera.Size size = mCamera.getParameters().getPreviewSize(); //获取预览大小
final int w = size.width; //宽度
final int h = size.height;
final YuvImage image = new YuvImage(data, ImageFormat.NV21, w, h, null);
// 转Bitmap
ByteArrayOutputStream os = new ByteArrayOutputStream(data.length);
if(! image.compressToJpeg(new Rect(0, 0, w, h), 100, os)) {
return;
}
byte[] tmp = os.toByteArray();
Bitmap bitmap = BitmapFactory.decodeByteArray(tmp, 0, tmp.length);
Bitmap rotatedBitmap = BitmapUtil.createRotateBitmap(bitmap);
cropBitmapAndRecognize(rotatedBitmap);
}
};
public void cropBitmapAndRecognize(Bitmap originalBitmap) {
// 裁剪出关注区域
DisplayMetrics metric = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metric);
int width = metric.widthPixels; // 屏幕宽度（像素）
int height = metric.heightPixels; // 屏幕高度（像素）
Bitmap sizeBitmap = Bitmap.createScaledBitmap(originalBitmap, width, height, true);
int rectWidth = (int)(mIvPlateRect.getWidth() * 1.5);
int rectHight = (int)(mIvPlateRect.getHeight() * 1.5);
int[] location = new int[2];
mIvPlateRect.getLocationOnScreen(location);
location[0] -= mIvPlateRect.getWidth() * 0.5 / 2;
location[1] -= mIvPlateRect.getHeight() * 0.5 / 2;
Bitmap normalBitmap = Bitmap.createBitmap(sizeBitmap, location[0], location[1], rectWidth, rectHight);
// 保存图片并进行车牌识别
File pictureFile = FileUtil.getOutputMediaFile(FileUtil.FILE_TYPE_PLATE);
if (pictureFile == null) {
Log.d(TAG, "Error creating media file, check storage permissions: ");
return;
}
try {
mTvPlateResult.setText("正在识别...");
FileOutputStream fos = new FileOutputStream(pictureFile);
normalBitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
fos.close();
// 最后通知图库更新
CameraActivity.this.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" pictureFile.getAbsolutePath())));
// 进行车牌识别
String plate = mPlateRecognizer.recognize(pictureFile.getAbsolutePath());
if (null != plate && ! plate.equalsIgnoreCase("0")) {
mTvPlateResult.setText(plate);
} else {
mTvPlateResult.setText("请调整角度");
}
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " e.getMessage());
}
}
}
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