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Strapakowsky
Asked: 2011-09-01 00:33:41 +0800 CST

How can I extract text from images?

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How can I extract text from images?

I am not talking about scanned files, but garden variety images, such as when you take a high-def picture of a blackboard at class, and it is nicely handwritten; or when you photograph a page from a recipe book and want the recipe in text format.

Any free and open software for that?

I tried tesseract, and the results were awful.

software-recommendation

3 Answers

  1. Best Answer

    The act of extracting text from images is called OCR and Ubuntu has a wiki page dedicated to OCR. From that page:

    Available OCR tools

    The Ubuntu Universe repositories contain the following OCR tools:

    1. gocr - A command line OCR
    2. fuzzyocr - spamassassin plugin to check image attachments
    3. libhocr0 - Hebrew OCR
    4. ocrad - Optical Character Recognition program
    5. ocrfeeder - Document layout analysis and optical character recognition system
    6. ocropus - document analysis and OCR system
    7. tesseract-ocr

    The Ubuntu multiverse respositories also contain:

    1. cuneiform - multi-language OCR system

    Some packages are outdated, but unofficial fresh ones can be found in Alex_P PPA (PPA adding code: ppa:alex-p/notesalexp). If you never used a PPA check how to add software from a PPA.

    edit: As shown in comment Clara OCR exists too but it got stuk at Hardy and their website has 2009 as last updated.

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  2. tesseract-ocr would be the great one compared to all others. For Installation, run the below command 

    sudo apt-get install tesseract-ocr

    Usage is tesseract filename.jpg output.txt, then it will generate output.txt file.

    You might consider selecting the appropriate language. In that case, you will need to install tesseract-ocr-LANG package, where LANG is the three-letter ISO 639-2 language code. Right now you have 123 languages on 18.04 repo. Then use for example:

    tesseract mySpanishText.jpg output -l spa
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  3. Using tesseract-ocr we can extract text from images. I have tested gocr which didn't work well as compare to tesseract-ocr

    Installation:

    sudo apt-get install tesseract-ocr

    Python program to convert all the image files with png extension inside of current directory to txt file

    #!/usr/bin/env python3.10
import os
import subprocess

def list_files(path):
    files = []
    for name in os.listdir(path):
        if os.path.isfile(os.path.join(path, name)):
            files.append(os.path.join(path, name))
    return files

def convertImageToText(img_file):
    #process = subprocess.Popen(['tesseract', img_file,
    #    ''.join(img_file.rsplit('.png', 1))])
    os.system(f"tesseract {img_file} {''.join(img_file.rsplit('.png', 1))}")


def startOperation():
    list_file = list_files(".")
    print(list_file)
    for img_file in list_file:
        if img_file.lower().split(".")[-1] == "png":
            convertImageToText(img_file)

startOperation()
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