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Fork of Tesseract Tools for Android.
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Latest commit 41e0f46 @rmtheis Merge pull request #124 from panzerfahrer/pr_issue-102
fix 64-bit ARMv8 build


A fork of Tesseract Tools for Android (tesseract-android-tools) that adds some additional functions. Tesseract Tools for Android is a set of Android APIs and build files for the Tesseract OCR and Leptonica image processing libraries.

This project works with Tesseract v3.04.00 and Leptonica v1.72. The required source code for Tesseract and Leptonica is included within the tess-two/jni folder.

The tess-two subdirectory contains tools for compiling the Tesseract and Leptonica libraries for use on the Android platform. It contains an Android library project that provides a Java API for accessing natively-compiled Tesseract and Leptonica APIs.

The eyes-two subdirectory contains a second, separate library project with additional image processing code copied from the eyes-free project. It includes native functions for text detection, blur detection, optical flow detection, and thresholding. Building eyes-two is not necessary for using the Tesseract or Leptonica APIs.

The tess-two-test subdirectory contains Android JUnit tests.


  • Android 2.2 or higher
  • A v3.02 trained data file for a language. Data files must be extracted to the Android device in a subdirectory named tessdata.


Release points are tagged with version numbers. A change to the major version number indicates an API change making that version incompatible with previous versions.


This project is set up to build on Android SDK Tools r22.3+ and Android NDK r10d+. The build works on Linux, Mac OS X, and Windows 7/8.

On 64-bit Ubuntu, you may need to install the ia32-libs 32-bit compatibility library.

To build the latest tess-two code, run the following commands in the terminal:

git clone git:// tess
cd tess
cd tess-two
android update project --path .
ant release

To build eyes-two, additionally run the following:

cd ..
cd eyes-two
android update project --path .
ant release

After building, the tess-two and eyes-two projects can be imported into Eclipse using File->Import->Existing Projects into Workspace.


While this project does not require Maven (and this project has not yet been registered in a Maven central repository), it can be integrated into a local Maven repository for convenience.


If you're using ProGuard for code shrinking and obfuscation, add the following rules to your app's ProGuard config to retain fields used for sharing data with native code:

# tess-two
-keep class {
    private long mNativeBox;
-keep class {
    private long mNativeBoxa;
-keep class {
    private long mNativePix;
-keep class {
    private long mNativePixa;
-keep class {
    private long mNativeData;
    protected void onProgressValues(int, int, int, int, int, int, int, int, int);
-keep class {
    private long mNativePageIterator;
-keep class {
    private long mNativePdfRenderer;
-keep class {
    private long mNativeResultIterator;
# eyes-two
-keep class com.googlecode.eyesfree.textdetect.HydrogenTextDetector {
    private long mNative;


If you've found an error in this project, please file an issue.

Patches are encouraged, and may be submitted by forking this project and submitting a pull request through GitHub.


Copyright 2011 Robert Theis

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
See the License for the specific language governing permissions and
limitations under the License.
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