python验证码解码器库 [英] python captcha decoder library

问题描述

我需要一个用于python的Captcha解码器来读取如下图所示的简单图像验证码：

I need a Captcha decoder for python to read simple image captchas like the following picture:

你知道一个可以帮我读这个验证码的图书馆吗？

Do you know of a library that can help me read this captcha?

如果你不知道用于阅读验证码的图书馆，你能帮我用PIL阅读这个（以及其他类似的东西）吗？

If you don't know of a library for reading captchas, could you help me to read this (and others like this) with PIL?

推荐答案

我希望这个验证码不会在任何地方使用。

I hope this captcha is not used anywhere.

以下是一种虚拟解码方式它。基本上你需要的是这些验证码中存在的从0到9的模式。从你的例子中，我只有0 3 4 5 7 8的模式。因为一切都固定在它们上面，你知道在哪里分割每个字符。您还知道每个字符都是一些固定大小和固定字体。如果它还包括字母或更多字符，但具有固定大小和字体，则可以轻松调整以下代码。

Following is a dummy way to decode it. Basically what you need are the patterns from 0 to 9 as present in these captchas. From your examples, I have only the patterns for 0 3 4 5 7 8. Since everything is fixed on them, you know where to split each character. You also know each character is a number of fixed size and fixed font. If it also includes letters or more characters, but of fixed size and font, then the following code can be easily adapted.

代码的作用是：a）加载模式（我认为它们被命名为n0.png，n1.png，...）; b）将验证码分成NUMS部分; c）在每个模式和每个分割数之间做一个平方差的和; d）确定分割数是具有最小总和的分割数。它按顺序返回每个数字的列表，显示在验证码中。要获取初始模式，您可以取消注释保存拆分号码的行，在该段后放置 return ，然后调整文件名。

What the code does is: a) load the patterns (I considered they are named n0.png, n1.png, ...); b) split the captcha in NUMS pieces; c) do a sum of squared differences between each pattern and each split number; d) decide that the the split number is the one with the smallest sum. It returns a list for each number, in order, present in the captcha. To obtain the initial patterns, you can uncomment the lines that save the split numbers, place a return after that piece, and adjust the file names.

import sys
from PIL import Image, ImageOps

PAT_SIZE = (8, 10)
NUMS = 3
FIRST_NUM_OFFSET = 5
NUM_OFFSET = (1, 3)


NUMBERS = []
for i in xrange(10):
    try:
        NUMBERS.append(Image.open('n%d.png' % i).load())
    except IOError:
        print "I do not know the pattern for the number %d." % i
        NUMBERS.append(None)


def magic(fname):
    captcha = ImageOps.grayscale(Image.open(fname))
    im = captcha.load()

    # Split numbers
    num = []
    for n in xrange(NUMS):
        x1, y1 = (FIRST_NUM_OFFSET + n * (NUM_OFFSET[0] + PAT_SIZE[0]),
                NUM_OFFSET[1])
        num.append(captcha.crop((x1, y1, x1 + PAT_SIZE[0], y1 + PAT_SIZE[1])))

    # If you want to save the split numbers:
    #for i, n in enumerate(num):
    #    n.save('%d.png' % i)

    def sqdiff(a, b):
        if None in (a, b): # XXX This is here just to handle missing pattern.
            return float('inf')

        d = 0
        for x in xrange(PAT_SIZE[0]):
            for y in xrange(PAT_SIZE[1]):
                d += (a[x, y] - b[x, y]) ** 2
        return d

    # Calculate a dummy sum of squared differences between the patterns
    # and each number. We assume the smallest diff is the number in the
    # "captcha".
    result = []
    for n in num:
        n_sqdiff = [(sqdiff(p, n.load()), i) for i, p in enumerate(NUMBERS)]
        result.append(min(n_sqdiff)[1])
    return result

print magic(sys.argv[1])

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