https://github.com/guitarmind/tesseract-web-service

An implementation of RESTful web service for tesseract-OCR using tornado
https://github.com/guitarmind/tesseract-web-service

Last synced: 8 months ago
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An implementation of RESTful web service for tesseract-OCR using tornado

• Host: GitHub
• URL: https://github.com/guitarmind/tesseract-web-service
• Owner: guitarmind
• License: apache-2.0
• Created: 2013-11-23T04:46:13.000Z (over 12 years ago)
• Default Branch: master
• Last Pushed: 2023-05-20T20:31:42.000Z (about 3 years ago)
• Last Synced: 2024-04-22T01:24:00.026Z (about 2 years ago)
• Language: Python
• Homepage:
• Size: 52.7 KB
• Stars: 135
• Watchers: 15
• Forks: 34
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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• awesome-ocr - tesseract-web-service - An implementation of RESTful web service for tesseract-OCR using tornado. (Software / OCR as a Service)

README

          
tesseract-web-service

=====================

An implementation of RESTful web service for tesseract-OCR. The HTTP server is implemented using tornado. A [**Docker Container**](https://registry.hub.docker.com/u/guitarmind/tesseract-web-service/) has been created to let you run this service without any installation efforts!

As of tesseract-ocr version 3.02.02, it provides a [C-API](https://code.google.com/p/tesseract-ocr/wiki/APIExample).

Now while calling the "Fetch Image From URL" API, operations are done in memory for better performance. No file I/O is required. The python implementation of C API wrapper using ctypes can be found in [**tesseractcapi.py**](https://github.com/guitarmind/tesseract-web-service/blob/master/tesseractcapi.py). Bulk processing is planned to appear in the future version.

A full list of C APIs supported in tesseract-ocr version 3.02.02 is at [here](https://code.google.com/p/tesseract-ocr/source/browse/api/capi.h) with detailed signatures and comments.

#### Support two APIs with GET and POST

    Upload Image File: /upload

    Fetch Image From URL: /fetchurl

#### Tesseract Installation on Ubuntu 12.04 LTS

Python Requirement

    version >= 2.7

Install tornado, PIL image library and other required packages by apt-get.

    sudo apt-get update && sudo apt-get install -y \

        autoconf \

        automake \

        autotools-dev \

        build-essential \

        checkinstall \

        libjpeg-dev \

        libpng-dev \

        libtiff-dev \

        libtool \

        python \

        python-imaging \

        python-tornado \

        wget \

        zlib1g-dev

You need to compile and install leptonica and the latest version (3.02.02) of tesseract-ocr manually to support C API. More details can be found at [this wiki](https://code.google.com/p/tesseract-ocr/wiki/Compiling). Here is an example on Ubuntu 12.04 LTS:

    mkdir ~/temp \

        && cd ~/temp/ \

        wget http://www.leptonica.org/source/leptonica-1.69.tar.gz \

        && tar -zxvf leptonica-1.69.tar.gz \

        && cd leptonica-1.69 \

        && ./configure \

        && make \

        && checkinstall \

        && ldconfig

    cd ~/temp/ \

        && wget https://tesseract-ocr.googlecode.com/files/tesseract-ocr-3.02.02.tar.gz \

        && tar xvf tesseract-ocr-3.02.02.tar.gz \

        && cd tesseract-ocr \

        && ./autogen.sh \

        && mkdir ~/local \

        && ./configure --prefix=$HOME/local/ \

        && make \

        && make install

Only English letters and digits are supported by default.

You can download more language packs, such as Simplified/Traditional Chinese pack from http://code.google.com/p/tesseract-ocr/downloads/list.

Decompress and put the packs under '**~/local/share/**' or other locations you like.

    mkdir ~/local/share -p

    cd ~/local/share \

        && wget https://tesseract-ocr.googlecode.com/files/tesseract-ocr-3.02.eng.tar.gz \

        && tar xvf tesseract-ocr-3.02.eng.tar.gz

    ls ~/local/share/tesseract-ocr/tessdata

    configs           eng.cube.params        eng.traineddata.__tmp__

    eng.cube.bigrams  eng.cube.size          equ.traineddata

    eng.cube.fold     eng.cube.word-freq     osd.traineddata

    eng.cube.lm       eng.tesseract_cube.nn  tessconfigs

    eng.cube.nn       eng.traineddata

Be sure to set the parent folder path of language packs in environment variables, for instance:

    export TESSDATA_PREFIX=/home/markpeng/local/share/tesseract-ocr/

#### How to start tesseract-web-service

Create a folder named '**static**' under current folder (for instance, '**/opt/ocr**') to keep temp files

    sudo mkdir /opt/ocr/static -p

Then put all .py files to /opt/ocr and make them executable.

    sudo cp ~/Share/tesseract-web-service/* /opt/ocr

    sudo chmod 755 /opt/ocr/*.py

Note: you should go to the folder path containing the **static** folder to make the service work.

    cd /opt/ocr

Now, start tesseract-web-service by:

    python tesseractserver.py -b "/home/markpeng/local/lib" -d "/home/markpeng/local/share/tesseract-ocr"

Type the following command to check the options.

    python tesseractserver.py -h

    Usage: tesseractserver.py [options]

    Options:

      -h, --help            show this help message and exit

      -p PORT, --port=PORT  the listening port of RESTful tesseract web service.

                            (default: 1688)

      -l LANG, --lang=LANG  the targe language. (default: eng)

      -b LIBPATH, --lib-path=LIBPATH

                            the absolute path of tesseract library.

      -d TESSDATA, --tessdata-folder=TESSDATA

                            the absolute path of tessdata folder containing

                            language packs.

The default listening port is **1688**. Change it to yours on startup.

Please make sure that the firewall is opened for listening port.

For example, you can change the port to 8080 by:

    python /opt/ocr/tesseractserver.py -p 8080 -b "/home/markpeng/local/lib" -d "/home/markpeng/local/share/tesseract-ocr"

To start it as a persistent service even after terminal logout:

    sudo nohup python /opt/ocr/tesseractserver.py -p 8080 -b "/home/markpeng/local/lib" -d "/home/markpeng/local/share/tesseract-ocr" &

#### Tesseract Installation on Ubuntu 14.04 LTS

Python Requirement

    version >= 2.7

Install tornado, PIL image library and other required packages by apt-get.

    sudo apt-get update && sudo apt-get install -y \

        autoconf \

        automake \

        autotools-dev \

        build-essential \

        checkinstall \

        libjpeg-dev \

        libpng-dev \

        libtiff-dev \

        libtool \

        python \

        python-imaging \

        python-tornado \

        wget \

        zlib1g-dev

Install the tesseract library:

    sudo apt-get install tesseract-ocr-dev

Correct the Filename( or use this Repository):

    class TesseactWrapper:

        def __init__(self, lang, libpath, tessdata):

            libname = libpath + "/libtesseract.so.3.0.3"

Check for English training data (Filename: eng.traineddata in /usr/share/tesseract-ocr/tessdata/).

If not exist do:

    wget https://tesseract-ocr.googlecode.com/files/eng.traineddata.gz

    gunzip eng.traineddata.gz

    sudo mv -v eng.traineddata /usr/local/share/tessdata/

Create a static folder in repo main directory:

    mkdir static

Now, start tesseract-web-service by:

    python tesseractserver.py -p 1688 -b /usr/lib -d /usr/share/tesseract-ocr/tessdata/

#### How to call RESTful API by GET/POST request

The web service provides two HTTP GET pages for testing the API:

    Upload Image File: http://localhost:1688/upload

    Fetch Image From URL: http://localhost:1688/fetchurl

The results are returned in JSON format with OCR result strings.

If you would like to call "Fetch Image From URL" API with POST, please send a HTTP request header similar to the following:

    POST /fetchurl HTTP/1.1

    Host: localhost:1688

    Connection: keep-alive

    Content-Length: 214

    Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8

    Origin: http://localhost:1688

    User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/30.0.1599.114 Safari/537.36

    Content-Type: multipart/form-data; boundary=----WebKitFormBoundarylFMK6PAyVCzNCDAr

    Referer: http://localhost:1688/fetchurl

    Accept-Encoding: gzip,deflate,sdch

    Accept-Language: zh-TW,zh;q=0.8,en-US;q=0.6,en;q=0.4d license

    .....

    POST data payload: imageUrl = 'http://xxxxxxx'

If you send POST data by JSON, you need to provide a '**url**' key, which contains target image url.

Example POST data in JSON:

    data: {

        'url': 'http://price1.suning.cn/webapp/wcs/stores/prdprice/89218_9173_10000_9-1.png'

    }

Then you shall get a JSON response similar to the following:

    data: {

        'url': 'http://price1.suning.cn/webapp/wcs/stores/prdprice/89218_9173_10000_9-1.png',

        'result': '2158.00'

    }

Note that for /upload API, since there is no url provided, only result string will be returned in JSON.

#### How to call RESTful API by tesseract client

tesseractclient.py is a client for calling the "Fetch Image From URL" API.

Type the following command to check the options.

    python /opt/ocr/tesseractclient.py --help

    Usage: tesseractclient.py [options]

    Options:

      -h, --help            show this help message and exit

      -a APIURL, --api-url=APIURL

                            the URL of RESTful tesseract web service

      -i IMAGEURL, --image-url=IMAGEURL

                            the URL of image to do OCR

For instance:

    python /opt/ocr/tesseractclient.py -a "http://localhost:1688/fetchurl" -i "http://www.greatdreams.com/666-magicsquare.gif"

You should provide the API url and image source url to make it work.

#### How to pull and run Docker Container

Install Docker to your host by following the [official installation guide](https://docs.docker.com/installation/#installation).

After that, execute the following command to download Docker Image (packaged in Ubuntu 12.04 LTS):

    docker pull guitarmind/tesseract-web-service

To run the web service using container, just type:

    docker run --rm -d -p 1688:1688 guitarmind/tesseract-web-service

Note that the -p flag is used to bind local port with Container's virtual port. By default it is set to 1688. You can change it by modifying the [Dockerfile](https://github.com/guitarmind/tesseract-web-service/blob/master/Dockerfile). The -d flag means to run it in daemon mode.

The container has been created as an Automated Build:

https://registry.hub.docker.com/u/guitarmind/tesseract-web-service/

## Changelog

#### 0.0.1 - 2013-11-23

Features:

  - Support basic GET/POST APIs for "upload" and "fetchUrl" APIs

  - File-based processing

#### 0.0.2 - 2013-12-08

Features:

  - Add a Python wrapper for calling tesseract-ocr C API directly

  - Memory-based processing for "fetchUrl" API

#### 0.0.3 - 2015-01-03

Features:

  - Add a Docker Container for easy installation and deployment

#### 0.0.4 - 2015-09-18

Features:

  - Fixed issue [#3](https://github.com/guitarmind/tesseract-web-service/issues/3)

  - Merged pull request [#1](https://github.com/guitarmind/tesseract-web-service/pull/1), [#2](https://github.com/guitarmind/tesseract-web-service/pull/2), [#4](https://github.com/guitarmind/tesseract-web-service/pull/4) and [#6](https://github.com/guitarmind/tesseract-web-service/pull/6) accordingly.

#### 0.0.5 - 2016-02-11

Features:

  - Fixed issue [#7](https://github.com/guitarmind/tesseract-web-service/issues/7)

## Copyright and License

Author: Mark Peng (markpeng.ntu at gmail)

All codes are under the [Apache 2.0 license](LICENSE).