Removewaternark | Python Fiddle

# coding:utf-8

from PIL import Image
import sys

def get_data(height, width, interval, datalen, start):
    # first line: 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0 ...
    data = []
    raw_line = [0] * interval
    raw_line.extend([1] * datalen)
    packlen = interval + datalen
    raw = raw_line * (int(width / packlen) + 2)
    start = packlen - start
    for i in xrange(height):
        if start > packlen:
            start = (start % packlen)
        data.extend(raw[start:start + width])
        start += 1
    return data

def get512():
    return get_data(512, 512, 13, 7, 3)

def get256():
    return get_data(256, 256, 13, 7, 3)

def get128():
    return get_data(128, 128, 13, 7, 3)

def get48():
    return get_data(48, 48, 5, 5, 2)

raw_data = {
    # 48: get48,
    128: get128,
    256: get256,
    512: get512
}

def transparent(point):
    if point[3] != 255 and (66 < point[0] < 70) and (66 < point[1] < 70) \
            and (62 < point[2] < 66):
        return True
    return False

def rec(x, i):
    a, b, c, d = x
    a = int((a - 68 * i) / (1 - i))
    b = int((b - 68 * i) / (1 - i))
    c = int((c - 64 * i) / (1 - i))
    return (a, b, c, d)

def unmark(filename):
    im = Image.open(filename)
    im = im.convert("RGBA")
    kk = im.load()
    func = raw_data.get(im.size[0])
    if not func:
        print "NOT SUPPORT SIZE (128, 256, 512)"
        sys.exit()

print "SIZE: ", im.size
    nodes = func()

for index, node in enumerate(nodes):
        if node == 0:
            continue

i = index % im.size[1]
        j = index / im.size[1]

if transparent(kk[i, j]):
            kk[i, j] = (0, 0, 0, 0)
        else:
            if (i > 1 and nodes[index - 1] == 0) or (j < im.size[1] - 1 and nodes[index + 1] == 0):
                kk[i, j] = rec(kk[i, j], 0.015)
            elif (i > 2 and nodes[index - 2] == 0) or (j < im.size[1] - 2 and nodes[index + 2] == 0):
                kk[i, j] = rec(kk[i, j], 0.065)
            else:
                kk[i, j] = rec(kk[i, j], 0.073)

new_name = filename.lower().replace(".png", ".new.png")

print "NEW: ", new_name
    im.save(new_name, "PNG")

def show(x, n):
    for i in xrange(n):
        for j in xrange(n):
            print x[i * n + j],
        print

if __name__ == '__main__':
    unmark(sys.argv[1])

Python Fiddle

Python Cloud IDE