android中ocr解決方案（tesseract）

android應用中ocr的解決方案大體有兩種，而採用最多的仍是tesseract.小弟就在這裏將我最近兩天解決思路寫下來，若有缺陷，歡迎拍磚：
　　有兩種解決方案，一種是採用tesseract cloud-service,這鐘是把圖片信息發送到雲端，而後得到圖片分析數據；第二種就是不用聯網，本地化分析圖片上信息。我就說說第二種,第一種我會在最後給你們一個連接（文章很不錯）。
　　搜先就是下載Tesseract native android library.這裏有兩個連接，你選哪一個連接均可以：
　　a.svn checkout http://tesseract-android-tools.googlecode.com/svn/trunk/ tesseract-android-tools。(若是不能checkout到，廢話別說就到官方上下:http://code.google.com/p/tesseract-android-tools/)
　　b.可能上面一個下載後編譯有些人會遇到一些問題，好比找不到jgep庫，編譯不成功。因此有了這個項目：git clone git://github.com/rmtheis/tess-two.git  （這個包裏面內容太多，不過也免得下那麼多庫了）
　　這裏先說採用第一個源下載：下載成功後，打開README文件，作下修改（以下）：
git clone git://android.git.kernel.org/platform/external/jpeg.git libjpeg
修改成：
git clone https://android.googlesource.com/platform/external/jpeg libjpeg
n
　　
　　對於第二個源下載，因爲裏面沒有README文件，操做命令以下：
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

　　最終兩個都獲得你想要的libs裏面的so文件和src裏面的對so文件的封裝類。這個就是咱們開發所用到的東東啦。
　　而後新建工程，代碼以下：
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";
   
    private TessBaseAPI service;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        testOcr();
       
    }
   
    public void testOcr(){
        mHandler.post(new Runnable() {
           
            @Override
            public void run() {
                Log.d(TAG, "begin>>>>>>>");
                ocr();
                //test();
            }
        });

    }
    public 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());*/
        final TessBaseAPI baseApi = new TessBaseAPI();
        baseApi.init(TESSBASE_PATH, DEFAULT_LANGUAGE);
        final 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();
    }
   
    protected 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());
        }
    }
    private Handler mHandler = new Handler(){
        public void handleMessage(android.os.Message msg) {
           
        };
    };
}

　　當你很歡喜的運行程序的時候，發現事情沒有你想象的那麼簡單。這個文件必需要用到一個語言包。否則你怎麼匹配呢？想一想也是：
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

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https://github.com/rmtheis/tess-two