使用 Tesseract 的 Android OCR 应用程序

Question

I was following the tutorial mentioned at this this site:

http://gaut.am/making-an-ocr-android-app-using-tesseract/

First I imported Tess-Two from github: https://github.com/rmtheis/tess-two

And linked it to my project https://github.com/GautamGupta/Simple-Android-OCR

The app compiles and runs fine. But after clicking an image when I hit save it crashes.

Here is the source main activity:

public class SimpleAndroidOCRActivity extends Activity {
  public static final String PACKAGE_NAME = "com.datumdroid.android.ocr.simple";
  public static final String DATA_PATH = Environment
                    .getExternalStorageDirectory().toString() + "/SimpleAndroidOCR/";

  // You should have the trained data file in assets folder
  // You can get them at:
  // http://code.google.com/p/tesseract-ocr/downloads/list
  public static final String lang = "eng";

  private static final String TAG = "SimpleAndroidOCR.java";

  protected Button _button;
  // protected ImageView _image;
  protected EditText _field;
  protected String _path;
  protected boolean _taken;

  protected static final String PHOTO_TAKEN = "photo_taken";

  @Override
  public void onCreate(Bundle savedInstanceState) {

    String[] paths = new String[] { DATA_PATH, DATA_PATH + "tessdata/" };

    for (String path : paths) {
      File dir = new File(path);
      if (!dir.exists()) {
        if (!dir.mkdirs()) {
          Log.v(TAG, "ERROR: Creation of directory " + path + " on sdcard failed");
          return;
        } else {
          Log.v(TAG, "Created directory " + path + " on sdcard");
        }
      }
    }

    // lang.traineddata file with the app (in assets folder)
    // You can get them at:
    // http://code.google.com/p/tesseract-ocr/downloads/list
    // This area needs work and optimization
    if (!(new File(DATA_PATH + "tessdata/" + lang + ".traineddata")).exists()) {
      try {
        AssetManager assetManager = getAssets();
        InputStream in = assetManager.open("tessdata/" + lang + ".traineddata");
        //GZIPInputStream gin = new GZIPInputStream(in);
        OutputStream out = new FileOutputStream(DATA_PATH
                                            + "tessdata/" + lang + ".traineddata");

        // Transfer bytes from in to out
        byte[] buf = new byte[1024];
        int len;
        //while ((lenf = gin.read(buff)) > 0) {
        while ((len = in.read(buf)) > 0) {
          out.write(buf, 0, len);
        }
        in.close();
        //gin.close();
        out.close();

        Log.v(TAG, "Copied " + lang + " traineddata");
      } catch (IOException e) {
        Log.e(TAG, "Was unable to copy " + lang + " traineddata " + e.toString());
      }
    }

    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    // _image = (ImageView) findViewById(R.id.image);
    _field = (EditText) findViewById(R.id.field);
    _button = (Button) findViewById(R.id.button);
    _button.setOnClickListener(new ButtonClickHandler());

    _path = DATA_PATH + "/ocr.jpg";
  }

  public class ButtonClickHandler implements View.OnClickListener {
    public void onClick(View view) {
      Log.v(TAG, "Starting Camera app");
        startCameraActivity();
      }
    }

  // Simple android photo capture:
  // http://labs.makemachine.net/2010/03/simple-android-photo-capture/

  protected void startCameraActivity() {
    File file = new File(_path);
    Uri outputFileUri = Uri.fromFile(file);

    final Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    intent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);

    startActivityForResult(intent, 0);
  }

  @Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    Log.i(TAG, "resultCode: " + resultCode);

    if (resultCode == -1) {
      onPhotoTaken();
    } else {
      Log.v(TAG, "User cancelled");
    }
  }

  @Override
  protected void onSaveInstanceState(Bundle outState) {
    outState.putBoolean(SimpleAndroidOCRActivity.PHOTO_TAKEN, _taken);
  }

  @Override
  protected void onRestoreInstanceState(Bundle savedInstanceState) {
    Log.i(TAG, "onRestoreInstanceState()");
    if (savedInstanceState.getBoolean(SimpleAndroidOCRActivity.PHOTO_TAKEN)) {
      onPhotoTaken();
    }
  }

  protected void onPhotoTaken() {
    _taken = true;

    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSampleSize = 4;

    Bitmap bitmap = BitmapFactory.decodeFile(_path, options);

    try {
      ExifInterface exif = new ExifInterface(_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);
      }

      // Convert to ARGB_8888, required by tess
      bitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true);

    } catch (IOException e) {
      Log.e(TAG, "Couldn't correct orientation: " + e.toString());
    }

    // _image.setImageBitmap( bitmap );

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

    TessBaseAPI baseApi = new TessBaseAPI();
    baseApi.setDebug(true);
    baseApi.init(DATA_PATH, lang);
    baseApi.setImage(bitmap);

    String recognizedText = baseApi.getUTF8Text();

    baseApi.end();

    // You now have the text in recognizedText var, you can do anything with it.
    // We will display a stripped out trimmed alpha-numeric version of it (if lang is eng)
    // so that garbage doesn't make it to the display.

    Log.v(TAG, "OCRED TEXT: " + recognizedText);

    if ( lang.equalsIgnoreCase("eng") ) {
        recognizedText = recognizedText.replaceAll("[^a-zA-Z0-9]+", " ");
    }

    recognizedText = recognizedText.trim();

    if ( recognizedText.length() != 0 ) {
      _field.setText(_field.getText().toString().length() == 0 ? recognizedText : _field.getText() + " " + recognizedText);
      _field.setSelection(_field.getText().toString().length());
    }     
    // Cycle done.
  }

  // www.Gaut.am was here
  // Thanks for reading!
}

And I know the error is towards the end in the following part:

TessBaseAPI baseApi = new TessBaseAPI();
baseApi.setDebug(true);
baseApi.init(DATA_PATH, lang);
baseApi.setImage(bitmap);

String recognizedText = baseApi.getUTF8Text();

baseApi.end();

Any idea why it might be crashing?

Answer 1

去解压你的目标 *.apk 文件，检查是否有一个包含 *.so 文件的libs文件夹。如果这是你的问题，请查看我之前回答过的这个链接。

Answer 2

The issue is with your path, you have to download a language in which you want to get a result from code.google.com/p/tesseract-ocr/downloads/list download (eg: tesseract-ocr-3.02.eng.tar.gz ) extract it and locate the file “yourLanguage.traineddata” (eg: “eng.traineddata” ) and put this file in your storage path in sd card, then you can get it as a path

TessBaseAPI mTess = new TessBaseAPI();
String datapath = Environment.getExternalStorageDirectory() + "/tesseract/";
String language = "eng";
File dir = new File(datapath + "tessdata/");
if (!dir.exists())
    dir.mkdirs();
mTess.init(datapath, language);
mTess.setImage(yourBitmapImage);
String result = mTess.getUTF8Text();
Toast.makeText(tesswork.this, "Result : " + result, Toast.LENGTH_LONG).show();

Answer 3

Are you using correct tessdata files ? if not go for this. https://github.com/tesseract-ocr/tesseract/wiki/Data-Files#data-files-for-version-304305

 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

Here may be permission issue while saving files to directory.

Or check lib folder of code directory it can be issue of libtess.so file not available for CPU architecture like x86,x64,mips,armv7.