由于本周工作的需要，我利用Java重构了之前自己C++实现的图像识别算法。因为自己之前只在慕课网上面看过一些Java基础入门教程，如下所示：
Java入门第一季Java入门第二季Java入门第三季所以，这五天利用Java重构图像识别算法，并进行Android开发的过程是痛苦的。我把自己实现的过程记录下来，以便遇到相关项目的小伙伴可以节省时间:)
安卓开发工具采用Android Studio 2.2.2，下载地址.
OpenCV采用steveliles基于OpenCV3.1.0编译的opencv-android1.
Tesseract-OCR 我利用了rmtheis封装好的tess-two2.
参考Android Studio上进行OpenCV 3.1开发 – JohnHany的博客，设置Android SDK。
Sync的过程可能会比较慢，需要下载tess-two和OpenCV-Android的aar文件，依据网速不同，需要等待10分钟左右。
在Android视图下，右击tesscv->java->com.jt.www.tesscv文件夹，选择New->Java Class，在弹出的Create New Class对话框的Name后面输入tesscv，点击OK。
tesscv.java package com.jt.www.tesscv; import android.graphics.Bitmap; import android.os.Environment; import android.util.Log; import com.googlecode.tesseract.android.TessBaseAPI; import org.opencv.android.Utils; import org.opencv.core.CvException; import org.opencv.core.CvType; import org.opencv.core.Mat; import org.opencv.imgproc.Imgproc; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; /** * Created by Administrator on 2016/12/2. */ public class tesscv { private final static String TAG = "TessCV"; private Bitmap m_phone; // The path of phone image private TessBaseAPI m_tessApi; // Tesseract API reference private String m_datapath; // The path to folder containing language data file private final static String m_lang = "eng"; // The default language of tesseract private InputStream m_instream; public tesscv(Bitmap phone, InputStream instream) { m_phone = phone; m_instream = instream; /// initial tesseract-ocr m_datapath = Environment.getExternalStorageDirectory().toString() + "/MyLibApp/tesscv/tesseract"; // make sure training data has been copied checkFile(new File(m_datapath + "/tessdata")); m_tessApi = new TessBaseAPI(); m_tessApi.init(m_datapath, m_lang); // 设置psm模式 //m_tessApi.setPageSegMode(TessBaseAPI.PageSegMode.PSM_SINGLE_BLOCK); // 设置白名单 //m_tessApi.setVariable(TessBaseAPI.VAR_CHAR_WHITELIST, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"); //m_tessApi.setVariable(TessBaseAPI.VAR_CHAR_WHITELIST, "0123456789"); } private void saveTmpImage(String name, Mat image) { Mat img = image.clone(); if (img.channels() ==3 ) { Imgproc.cvtColor(img, img, Imgproc.COLOR_BGR2RGBA); } Bitmap bmp = null; try { bmp = Bitmap.createBitmap(img.cols(), img.rows(), Bitmap.Config.ARGB_8888); Utils.matToBitmap(img, bmp); } catch (CvException e) { Log.d("mat2bitmap", e.getMessage()); } File mediaStorageDir = new File(Environment.getExternalStorageDirectory(), "MyLibApp/tesscv"); if (!mediaStorageDir.exists()) { if (!mediaStorageDir.mkdirs()) { Log.d("saveTmpImage", "failed to create directory"); return; } } //String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date()); //File dest = new File(mediaStorageDir.getPath() + File.separator + name + timeStamp + ".png"); File dest = new File(mediaStorageDir.getPath() + File.separator + name + ".png"); FileOutputStream out = null; try { out = new FileOutputStream(dest); bmp.compress(Bitmap.CompressFormat.PNG, 100, out); // bmp is your Bitmap instance // PNG is a lossless format, the compression factor (100) is ignored } catch (Exception e) { e.printStackTrace(); } finally { if (out != null) { try { out.close(); } catch (IOException e) { e.printStackTrace(); } } } } public String getOcrOfBitmap() { if (m_phone == null) { return ""; } Mat imgBgra = new Mat(m_phone.getHeight(), m_phone.getWidth(), CvType.CV_8UC4); Utils.bitmapToMat(m_phone, imgBgra); Mat imgBgr = new Mat(); Imgproc.cvtColor(imgBgra, imgBgr, Imgproc.COLOR_RGBA2BGR); Mat img = imgBgr; saveTmpImage("srcInputBitmap", img); if (img.empty()) { return ""; } if (img.channels()==3) { Imgproc.cvtColor(img, img, Imgproc.COLOR_BGR2GRAY); } return getResOfTesseractReg(img); } private String getResOfTesseractReg(Mat img) { String res; if (img.empty()) { return ""; } byte[] bytes = new byte[(int)(img.total()*img.channels())]; img.get(0, 0, bytes); m_tessApi.setImage(bytes, img.cols(), img.rows(), 1, img.cols()); res = m_tessApi.getUTF8Text(); return res; } private void checkFile(File dir) { //directory does not exist, but we can successfully create it if (!dir.exists() && dir.mkdirs()){ copyFiles(); } //The directory exists, but there is no data file in it if(dir.exists()) { String datafilepath = dir.toString() + "/eng.traineddata"; File datafile = new File(datafilepath); if (!datafile.exists()) { copyFiles(); } } } private void copyFiles() { try { if (m_instream == null) { //TODO String resInPath = "/tessdata/eng.traineddata"; //Log.d(TAG, "copyFiles: resInPath " + resInPath); m_instream = new FileInputStream(resInPath); } //location we want the file to be a String resOutPath = m_datapath + "/tessdata/eng.traineddata"; //open byte streams for writing OutputStream outstream = new FileOutputStream(resOutPath); //copy the file to the location specified by filepath byte[] buffer = new byte[1024]; int read; while ((read = m_instream.read(buffer)) != -1) { outstream.write(buffer, 0, read); } outstream.flush(); outstream.close(); m_instream.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } }依次修改Android视图下，app文件内的AndroidManifest.xml、activity_main.xml和MainActivity.java三个文件。
app->manifests->AndroidManifest.xml <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.jt.www.mylibapp"> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest> app->res->layout->activity_main.xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity" android:weightSum="1"> <Button android:id="@+id/photo_album" android:text="PhotoAlbum" android:layout_height="50dp" android:layout_width="match_parent" /> <ImageView android:id="@+id/imageID" android:layout_width="match_parent" android:layout_height="360dip" /> <TextView android:id="@+id/OCRTextView" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="OCR Text will appear here..." android:textSize="18dip" android:layout_centerVertical="true" android:layout_centerHorizontal="true" android:textColor="#a3a3a3" /> <!--android:background="#dedede"--> </LinearLayout> app->java->com.jt.www.mylibapp->MainActivity.java package com.jt.www.mylibapp; import android.content.Intent; import android.content.res.AssetManager; import android.graphics.Bitmap; import android.net.Uri; import android.os.Bundle; import android.provider.MediaStore; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.Button; import android.widget.ImageView; import android.widget.TextView; import com.jt.www.tesscv.tesscv; import java.io.IOException; import java.io.InputStream; import org.opencv.android.OpenCVLoader; public class MainActivity extends AppCompatActivity { public static final String IMAGE_UNSPECIFIED = "image/*"; public static final int PHOTOALBUM = 1; // 相册 Button photo_album = null; // 相册 ImageView imageView = null; // 截取图像 TextView textView = null; // OCR 识别结果 Bitmap m_phone; // Bitmap图像 String m_ocrOfBitmap; // Bitmap图像OCR识别结果 InputStream m_instream; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); imageView = (ImageView) findViewById(R.id.imageID); photo_album = (Button) findViewById(R.id.photo_album); textView = (TextView) findViewById(R.id.OCRTextView); photo_album.setOnClickListener(new View.OnClickListener(){ @Override public void onClick(View v) { Intent intent = new Intent(Intent.ACTION_PICK, null); intent.setDataAndType(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, IMAGE_UNSPECIFIED); startActivityForResult(intent, PHOTOALBUM); } }); //get access to AssetManager AssetManager assetManager = getAssets(); //open byte streams for reading/writing try { m_instream = assetManager.open("tessdata/eng.traineddata"); } catch (IOException e) { e.printStackTrace(); } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (resultCode == 0 || data == null) { return; } // 相册 if (requestCode == PHOTOALBUM) { Uri image = data.getData(); try { m_phone = MediaStore.Images.Media.getBitmap(getContentResolver(), image); } catch (IOException e) { e.printStackTrace(); } } // 处理结果 imageView.setImageBitmap(m_phone); if (OpenCVLoader.initDebug()) { // do some opencv stuff tesscv jmi = new tesscv(m_phone, m_instream); m_ocrOfBitmap = jmi.getOcrOfBitmap(); } textView.setText(m_ocrOfBitmap); super.onActivityResult(requestCode, resultCode, data); } }小米5标准版，测试截图如下所示：
按照上图打开tesscv-release.aar文件所在目录，将tesscv-release.aar重命名为tesscv-1.0.0.aar
参考上述工程中添加tesseract-ocr语言库eng.traineddata方法。
Simple OCR Android App Using Tesseract Tutorial
How to manually include external aar package using new Gradle Android Build System - Stack Overflow
拍照+相册选取+剪裁图片，不过百行代码搞定 - JavAndroid - 博客频道 - .NET
