Tesseract with andoird and gradle
About tesseract
Tesseract is an Open Source OCR library
More info - https://code.google.com/p/tesseract-ocr/
Tesseract in android
If you are using tesseract library in android application, there is a previously built android application project exists(A fork of tesseract tools for android).
More info - https://github.com/rmtheis/tess-two
You have to build this tess-two project with android-ndk and then add the build project as library project to you android project. But this tess-two library not supports for build with gradle android projects. So we have to create gradle project with tess-two(configure tesst-two with gradle)
Configure tess-two with gradle
There are few steps you need to follow when integrating tesst-two with gradle android project.
Create a libraries folder underneath your project's main directory. For example, if your project is FirstProject, you would create a FirstProject/libraries folder
Now copy the entire tess-two directory into the libraries folder you just created.
Delete the libs folder in the tess-two directory. If you like, delete the project.properties, build.xml, .classpath, and .project. files as well. You don't need them.
Create a build.gradle file in the tess-two directory, (I have created a build.gradle file, you can just reuse it). Following is my build.gradle file
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath 'com.android.tools.build:gradle:0.9.+'
}
}
apply plugin: 'android-library'
android {
compileSdkVersion 19
buildToolsVersion "19.0.3"
defaultConfig {
minSdkVersion 8
_targetSdkVersion 19
}
sourceSets.main {
manifest.srcFile 'AndroidManifest.xml'
java.srcDirs = ['src']
resources.srcDirs = ['src']
res.srcDirs = ['res']
jniLibs.srcDirs = ['libs']
}
}
https://github.com/erangaeb/dev-notes/blob/master/tesseract/build.gradle
- Edit your settings.gradle file in your application’s(FirstProject/settings.gradle) main directory and add this line
include ':libraries:tess-two'
- Then sync the project in Android Studio and add the new tess-two library as module dependency to you main project(after sync tess-two library should appear as a module, you can add it to your project from project settings in android studio)
Written by eranga bandara
Related protips
36 Responses
How do we use it then, can you give an example?
Hi,
Following is a really good tutorial about tesseract android integration.
http://wolfpaulus.com/jounal/android-journal/android-and-ocr/
If you are using gradle to build your android app, you can use the build script that I have posted above(to build tesseract library as an android library project).
Thank you I found it already and I think it is really good.
What should there be if it says that a newer version of gradle should be used here com.android.tools.build:gradle:0.9.+ (at least 12.0) change it to 12.0+?
What is the gradle version you have installed?
The newest that comes with AS 0.8.
i did everything as you described, how can i import the library into an activity?
TessBaseAPI baseApi = new TessBaseAPI();
baseApi.setDebug(true);
baseApi.init(DATA_PATH, LANG);
baseApi.setImage(bitmap);
String recognizedText = baseApi.getUTF8Text();
baseApi.end();
(It described in the tutorial that I have posted in previous comment)
Hi!
I did everything that you said, but unfortunately, my app keeps crashing and I have this error in logcat : Couldn't load lept from loader dalvik.system.PathClassLoader[...]: findLibrary returned null
Do you have any idea what can cause that?
Did you build the tesseract library with android-ndk ??
Seems like "liblept.so" (shared library) file can not found on specific library path
Hi eranga,
Nice guide as i am able to blend tesseract with my android studio project, just one issue when i try to make module it kept on saying "Error:(14, 40) error: package com.googlecode.tesseract.android does not exist" even though i've set it as a dependency and import it to my code
Thank you for posting this. Very useful!
Thank you. Follow all steps, it is correct.
If someone has project including tess-two in Eclipse, now convert to Android Studio, should remove directory tess-two from generating. In build.gradle, remove:
compile project(':tesstwo')
I followed the steps and got this error:
java.lang.UnsatisfiedLinkError: Couldn't load lept from loader dalvik.system.PathClassLoader[dexPath=/data/app/br.com.notasocial.cupom-38.apk,libraryPath=/data/app-lib/br.com.notasocial.cupom-38]: findLibrary returned null
thrown by "new TessBaseAPI();"
Folder structure:
http://www.italomaia.com/media/uploads/tree01.png
http://www.italomaia.com/media/uploads/tree02.png
I followed all the steps. I am still getting the following error on running my app.
Error:(15, 40) error: package com.googlecode.tesseract.android does not exist
Any ideas are greatly appreciated.
Hi.... Even i got the same error - java.lang.UnsatisfiedLinkError: Couldn't load lept from loader.
Is there any particular reason why we should delete the libs folder from the tess-two library?
Issue Resolved :) .libs folder shouldn't be removed
After spending a whole day on trying to compile, build and redoing it all many times, Finally a solution that works. Thanks a lot Mr. bandara
I dont' find "project settings" in android studio, pls help. I'am stuck at the last step. Did you compile tess-two with 32/64bits ndk? Thanks D:
Hi this example is best
http://www.codeproject.com/Tips/840623/Android-Character-Recognition
https://code.google.com/p/android/issues/detail?id=74132 does anyone have a solution to this problem?
I solved my problem above, Ctrl+alt+shift+s ->Dependencies
Use ndk-build to build the tess-two library. If you have already built it before copying to libraries, then don't delete the libs folder. Rest everything worked like charm. Thanks a lot.
Hi, after adding it as a module dependency, it shows "Error: Configuration with name 'default' not found". May i know whats wrong? Everything was working fine before that. Thank you!
After adding library to settings.gradle file. I got following error:
Error:A problem occurred configuring project ':app'.
A problem occurred configuring project ':libraries:tess-two'.
java.io.FileNotFoundException: /home/usr/OCRApplication/libraries/tess-two/AndroidManifest.xml (No such file or directory)
To fix this issue, I modified the code as:
sourceSets.main {
manifest.srcFile 'src/main/AndroidManifest.xml'
java.srcDirs = ['src']
resources.srcDirs = ['src']
res.srcDirs = ['res']
jniLibs.srcDirs = ['libs']
}
By this change, I got list of errors and build failed. Here are few errors:
Error:(16, 27) error: package org.piccolo2d.nodes does not exist
Error:(24, 19) error: package javax.swing does not exist
Error:(25, 19) error: package javax.swing does not exist
Error:(28, 3) error: cannot find symbol class JMenuItem
Error:(35, 43) error: cannot find symbol class JMenuItem
Error:(48, 19) error: cannot find symbol class JMenu
I spent a lot of time but no luck. What's wrong here.
Please reply ASAP. Thanks for prompt response.
thanks dude.. you made my day. But only correction to be made is we should not remove libs folder and _target version in gradle file of our app and tess-two should be same.
The libs folder is REQUIRED for the app to work. If the libs folder is missing from the commit of tess-two obtained from github, Use ndk to build the tess-two project. But everything else works okay. Thanks.
hi, should i really add the whole tess-two directory to my project? after android-ndk the directory is about 400mb! thanks
Hi, am new to this and I would like to play with tess on android. So far I managed to build the tess two library with NDK10 but am stuck with android update project --path and ant release (android not a valid command). Ant has something to do with Apache so I guess I have to install ant, but what's update project command and what the path var means? Am already on a terminal inside tess two folder and after building with SDK I noticed the files changed close to an android build with a manifest and build xml file. Am using android studio so do I just have to copy tess two file to MyLib folder or do I have to go trough android update project --path and ant release first before I copy the folder to my MyLib folder?
Regards
a fellow senior programmer.
Use this if you are using latest Android Studio.
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:1.5.0'
}
}
apply plugin: 'android-library'
android {
compileSdkVersion 23
buildToolsVersion "23.0.2"
defaultConfig {
minSdkVersion 15
_targetSdkVersion 21
}
sourceSets.main {
manifest.srcFile 'AndroidManifest.xml'
java.srcDirs = ['src']
resources.srcDirs = ['src']
res.srcDirs = ['res']
jniLibs.srcDirs = ['libs']
}
}
It worked for me :)
I am following the steps mentioned above
In Configure tess-two with gradle tells to copy and paste the tess-two folder to my Project but when I paste, I get an error stating Cannot create class-file and none of my `.java' files get copied.
Where am I going wrong?
This article is outdated. tess-two
can now be used directly with gradle: compile 'com.rmtheis:tess-two:5.4.1'
. See this
Error:(4, 0) Plugin with id 'com.github.dcendents.android-maven' not found.
does anyone know how to fix this...
Hey,I have tried this and the project is workin...thanks for that but the output is bit weird.....
Like if the text contains 10 words only one word is correct rest all are just symbols or random letters..
Do we have to copy the eyes-two directory also or is it the whole tess-two master that we have to copy...
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