android中ocr解决方案（tesseract） - 快车库

android应用中ocr的解决方案大致有两种，而采用最多的还是tesseract.小弟就在这里将我最近两天解决思路写下来，如有缺陷，欢迎拍砖：
　　有两种解决方案，一种是采用tesseract cloud-service,这钟是把图片信息发送到云端，然后获得图片分析数据；第二种就是不用联网，本地化分析图片上信息。我就说说第二种,第一种我会在最后给大家一个链接（文章很不错）。
　　搜先就是下载Tesseract native android library.这里有两个链接，你选哪个链接都可以：
　　a.svn checkout http://tesseract-android-tools.googlecode.com/svn/trunk/ tesseract-android-tools。(如果不能checkout到，废话别说就到官方上下:http://code.google.com/p/tesseract-android-tools/)
　　b.可能上面一个下载后编译有些人会遇到一些问题，比如找不到jgep库，编译不成功。所以有了这个项目：git clone git://github.com/rmtheis/tess-two.git （这个包里面内容太多，不过也省得下那么多库了）
　　这里先说采用第一个源下载：下载成功后，打开README文件，做下修改（如下）：
git clone git://android.git.kernel.org/platform/external/jpeg.git libjpeg
修改为：
git clone https://android.googlesource.com/platform/external/jpeg libjpeg
n
　　
　　对于第二个源下载，由于里面没有README文件，操作命令如下：
cd <project-directory>/tess-two
export TESSERACT_PATH=${PWD}/external/tesseract-3.01
export LEPTONICA_PATH=${PWD}/external/leptonica-1.68
export LIBJPEG_PATH=${PWD}/external/libjpeg
ndk-build
android update project --path .
ant release

　　最终两个都得到你想要的libs里面的so文件和src里面的对so文件的封装类。这个就是我们开发所用到的东东啦。
　　然后新建工程，代码如下：
public class MainActivity extends Activity {

private static final String TAG = "MainActivity ...";

private static final String TESSBASE_PATH = "/mnt/sdcard/tesseract/";
private static final String DEFAULT_LANGUAGE = "eng";
private static final String IMAGE_PATH = "/mnt/sdcard/test1.jpg";
private static final String EXPECTED_FILE = TESSBASE_PATH + "tessdata/" + DEFAULT_LANGUAGE

".traineddata";

TessBaseAPI service;
@Override

void onCreate(Bundle savedInstanceState) {

   super.onCreate(savedInstanceState);
   setContentView(R.layout.main);
   testOcr();

}

void testOcr(){

   mHandler.post(new Runnable() {
      
       @Override
       public void run() {
           Log.d(TAG, "begin>>>>>>>");
           ocr();
           //test();
       }
   });

}

void test(){

   // First, make sure the eng.traineddata file exists.
   /*assertTrue("Make sure that you've copied " + DEFAULT_LANGUAGE + ".traineddata to "

- EXPECTED_FILE, new File(EXPECTED_FILE).exists());*/

TessBaseAPI baseApi = new TessBaseAPI();

  baseApi.init(TESSBASE_PATH, DEFAULT_LANGUAGE);

Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.test);

  //digits is a .jpg image I found in one of the issues here.
  ImageView img = (ImageView) findViewById(R.id.image);
  img.setImageBitmap(bmp);//I can see the ImageView. So we know that it should work if I sent it to the setImage()
  baseApi.setImage(bmp);
  Log.v("Kishore","Kishore:Working");//This statement is never reached. Futhermore, on putting some more Log.v commands in the setImage function, I found out that the native function nativeSetImagePix is never accessed. I have attached the Logcat output below to show that it is not accessed.
 
  String outputText = baseApi.getUTF8Text();
  Log.v("Kishore","Kishore:"+outputText);
  baseApi.end();
  bmp.recycle();

}

void ocr() {

   
   BitmapFactory.Options options = new BitmapFactory.Options();
   options.inSampleSize = 2;
   Bitmap bitmap = BitmapFactory.decodeFile(IMAGE_PATH, options);

   try {
       ExifInterface exif = new ExifInterface(IMAGE_PATH);
       int exifOrientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);

       Log.v(TAG, "Orient: " + exifOrientation);

       int rotate = 0;
       switch (exifOrientation) {
           case ExifInterface.ORIENTATION_ROTATE_90:
               rotate = 90;
               break;
           case ExifInterface.ORIENTATION_ROTATE_180:
               rotate = 180;
               break;
           case ExifInterface.ORIENTATION_ROTATE_270:
               rotate = 270;
               break;
       }

       Log.v(TAG, "Rotation: " + rotate);

       if (rotate != 0) {

           // Getting width & height of the given image.
           int w = bitmap.getWidth();
           int h = bitmap.getHeight();

           // Setting pre rotate
           Matrix mtx = new Matrix();
           mtx.preRotate(rotate);

           // Rotating Bitmap
           bitmap = Bitmap.createBitmap(bitmap, 0, 0, w, h, mtx, false);
           // tesseract req. ARGB_8888
           bitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true);
       }

   } catch (IOException e) {
       Log.e(TAG, "Rotate or coversion failed: " + e.toString());
   }

   ImageView iv = (ImageView) findViewById(R.id.image);
   iv.setImageBitmap(bitmap);
   iv.setVisibility(View.VISIBLE);

   Log.v(TAG, "Before baseApi");

   TessBaseAPI baseApi = new TessBaseAPI();
   baseApi.setDebug(true);
   baseApi.init(TESSBASE_PATH, DEFAULT_LANGUAGE);
   baseApi.setImage(bitmap);
   String recognizedText = baseApi.getUTF8Text();
   baseApi.end();

   Log.v(TAG, "OCR Result: " + recognizedText);

   // clean up and show
   if (DEFAULT_LANGUAGE.equalsIgnoreCase("eng")) {
       recognizedText = recognizedText.replaceAll("[^a-zA-Z0-9]+", " ");
   }
   if (recognizedText.length() != 0) {
       ((TextView) findViewById(R.id.field)).setText(recognizedText.trim());
   }

}

Handler mHandler = new Handler(){

   public void handleMessage(android.os.Message msg) {
      
   };

};
}

　　当你很欢喜的运行程序的时候，发现事情没有你想象的那么简单。这个文件必须要用到一个语言包。不然你怎么匹配呢？想想也是：
adb shell mkdir /mnt/sdcard/tesseract
adb shell mkdir /mnt/sdcard/tesseract/tessdata
adb push eng.traineddata /mnt/sdcard/tesseract/tessdata/eng.traineddata
adb shell ls -l /mnt/sdcard/tesseract/tessdata
ls -l bin/tesseract-android-tools-test.apk
adb install -r -s bin/tesseract-android-tools-test.apk
adb shell am instrument -w -e class com.googlecode.tesseract.android.test.TessBaseAPITest