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
ndk-build //这个编译要到jni文件夹里面编译
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";
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) {
};
};
}
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 com.googlecode.tesseract.android.test/android.test.InstrumentationTestRunner
上面的额eng.traineddata这个东西。你可以搜下，网络有的。（囧，我还不知到怎么上传附件）
最后效果如图（事实上解析结果是：44m><9。只不过那个字符不认识吧）：
参考文章：
http://wolfpaulus.com/journal/android-and-ocr
http://labs.makemachine.net/2010/03/simple-android-photo-capture/
