Document Image Binarization

There are two parts in this repo. The first part is written in python, which enable a simple binarization algorithm.

The second part uses an improved contrast maximization version of Niblack/Sauvola et al’s method to binarize document images. It is also able to perform the more classical Niblack as well as Sauvola et al. methods. Details can be found in the ICPR 2002 paper.

Usage:

Simple Binarization Algorithm

The first algorithem is easy enough, convert the colorful picture into ‘L’ model, then check the RGB value with an alpha=127. Main code can be found here:

import os, sys
from PIL import Image

inFile = ''
outFile = ''

if len(sys.argv) != 3:
    print 'Input format error!'
else:
    inFile = sys.argv[1]
    outFile = sys.argv[2]

im = Image.open(inFile).convert('L')

for i in range(im.size[0]):
    for j in range(im.size[1]):
        if im.getpixel((i,j)) > 127:
            im.putpixel((i,j), 255)
        else:
            im.putpixel((i,j), 0)

im.show()
im.save(outFile)

In order to run this code, run