android中ocr解決方案（tesseract）

　　android應用中ocr的解決方案大致有兩種，而採用最多的還是tesseract.小弟就在這裡將我最近兩天解決思路寫下來，如有缺陷，歡迎拍磚：

　　有兩種解決方案，一種是採用tesseract cloud-service,這鐘是把圖片資訊發送到雲端，然後獲得圖片分析資料；第二種就是不用連網，本地化分析圖片上資訊。我就說說第二種,第一種我會在最後給大家一個連結（文章很不錯）。

　　搜先就是下載Tesseract native android library.這裡有兩個連結，你選哪個連結都可以：

　　a.svn checkout http://tesseract-android-tools.googlecode.com/svn/trunk/ tesseract-android-tools。(如果不能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，比如找不到jgep庫，編譯不成功。所以有了這個項目：git clone git://github.com/rmtheis/tess-two.git  （這個包裡面內容太多，不過也省得下那麼多庫了）

　　這裡先說採用第一個源下載：下載成功後，開啟README檔案，做下修改（如下）：

git clone git://android.git.kernel.org/platform/external/jpeg.git libjpeg

修改為：

git clone https://android.googlesource.com/platform/external/jpeg libjpeg

ndk-build //這個編譯要到jni檔案夾裡面編譯

　　

　　對於第二個源下載，由於裡面沒有README檔案，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

　　最終兩個都得到你想要的libs裡面的so檔案和src裡面的對so檔案的封裝類。這個就是我們開發所用到的東東啦。

　　然後建立工程，代碼如下：

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";

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式的時候，發現事情沒有你想象的那麼簡單。這個檔案必須要用到一個語言套件。不然你怎麼匹配呢？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 com.googlecode.tesseract.android.test/android.test.InstrumentationTestRunner

　　上面的額eng.traineddata這個東西。你可以搜下，網路有的。（囧，我還不知到怎麼上傳附件）

　　最後效果（事實上解析結果是：44m><9。只不過那個字元不認識吧）：

                                    

參考文章：

　　http://wolfpaulus.com/journal/android-and-ocr

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