All Tesseract OCR options

This is for my reference and this might come in handy for others too.

All Tesseract options

$ tesseract --help-extra

Usage:
  tesseract --help | --help-extra | --help-psm | --help-oem | --version
  tesseract --list-langs [--tessdata-dir PATH]
  tesseract --print-parameters [options...] [configfile...]
  tesseract imagename|imagelist|stdin outputbase|stdout [options...] [configfile...]
OCR options:
  --tessdata-dir PATH   Specify the location of tessdata path.
  --user-words PATH     Specify the location of user words file.
  --user-patterns PATH  Specify the location of user patterns file.
  -l LANG[+LANG]        Specify language(s) used for OCR.
  -c VAR=VALUE          Set value for config variables.
                        Multiple -c arguments are allowed.
  --psm NUM             Specify page segmentation mode.
  --oem NUM             Specify OCR Engine mode.
NOTE: These options must occur before any configfile.
Page segmentation modes:
  0    Orientation and script detection (OSD) only.
  1    Automatic page segmentation with OSD.
  2    Automatic page segmentation, but no OSD, or OCR.
  3    Fully automatic page segmentation, but no OSD. (Default)
  4    Assume a single column of text of variable sizes.
  5    Assume a single uniform block of vertically aligned text.
  6    Assume a single uniform block of text.
  7    Treat the image as a single text line.
  8    Treat the image as a single word.
  9    Treat the image as a single word in a circle.
 10    Treat the image as a single character.
 11    Sparse text. Find as much text as possible in no particular order.
 12    Sparse text with OSD.
 13    Raw line. Treat the image as a single text line,
       bypassing hacks that are Tesseract-specific.
OCR Engine modes: (see https://github.com/tesseract-ocr/tesseract/wiki#linux)
  0    Legacy engine only.
  1    Neural nets LSTM engine only.
  2    Legacy + LSTM engines.
  3    Default, based on what is available.
Single options:
  -h, --help            Show minimal help message.
  --help-extra          Show extra help for advanced users.
  --help-psm            Show page segmentation modes.
  --help-oem            Show OCR Engine modes.
  -v, --version         Show version information.
  --list-langs          List available languages for tesseract engine.
  --print-parameters    Print tesseract parameters.

CLI Examples

Quickstart guide for pytesseract

try:
    from PIL import Image
except ImportError:
    import Image
import pytesseract
# If you don't have tesseract executable in your PATH, include the following:
pytesseract.pytesseract.tesseract_cmd = r'<full_path_to_your_tesseract_executable>'
# Example tesseract_cmd = r'C:\Program Files (x86)\Tesseract-OCR\tesseract'
# Simple image to string
print(pytesseract.image_to_string(Image.open('test.png')))
# French text image to string
print(pytesseract.image_to_string(Image.open('test-european.jpg'), lang='fra'))
# In order to bypass the image conversions of pytesseract, just use relative or absolute image path
# NOTE: In this case you should provide tesseract supported images or tesseract will return error
print(pytesseract.image_to_string('test.png'))
# Batch processing with a single file containing the list of multiple image file paths
print(pytesseract.image_to_string('images.txt'))
# Timeout/terminate the tesseract job after a period of time
try:
    print(pytesseract.image_to_string('test.jpg', timeout=2)) # Timeout after 2 seconds
    print(pytesseract.image_to_string('test.jpg', timeout=0.5)) # Timeout after half a second
except RuntimeError as timeout_error:
    # Tesseract processing is terminated
    pass
# Get bounding box estimates
print(pytesseract.image_to_boxes(Image.open('test.png')))
# Get verbose data including boxes, confidences, line and page numbers
print(pytesseract.image_to_data(Image.open('test.png')))
# Get information about orientation and script detection
print(pytesseract.image_to_osd(Image.open('test.png')))
# Get a searchable PDF
pdf = pytesseract.image_to_pdf_or_hocr('test.png', extension='pdf')
with open('test.pdf', 'w+b') as f:
    f.write(pdf) # pdf type is bytes by default
# Get HOCR output
hocr = pytesseract.image_to_pdf_or_hocr('test.png', extension='hocr')
# Executing with extra parameters supported by Tessseract command line 
image_to_data(image, lang=None, config='', nice=0, output_type=Output.STRING, timeout=0, pandas_config=None)
# Example of adding any additional options. custom_oem_psm_config = r'--oem 3 --psm 6' pytesseract.image_to_string(image, config=custom_oem_psm_config)

#Supported output types for pytesseract, Output.BYTES, Output.DICT, Output.STRING
# usage
print(pytesseract.image_to_data(region.image, config='--psm 10', output_type='dict'))
print(pytesseract.image_to_data(region.image, config='--psm 10', output_type='string'))
print(pytesseract.image_to_data(region.image, config='--psm 10', output_type='bytes'))

List of all Tesseract Parameters as of version 3.0

$ tesseract --print-parameters

List of available languages in Tesseract which can be installed using the command sudo apt install tesseract-ocr-langcode

References:

https://github.com/tesseract-ocr/tesseract
https://tesseract-ocr.github.io/
https://pypi.org/project/pytesseract/