python生成图片验证码

import random
import string
from PIL import Image, ImageFont, ImageDraw
import numpy as np
import math
from scipy import misc
import os

#字符集
characters = string.digits + string.ascii_letters


class GenerateImageCaptcha(object):

    def __init__(self, width=160, height=60, fonts=None, font_sizes=None):
        self._width = width
        self._height = height
        self._fonts = fonts or [r'C:\Windows\Fonts\arial.ttf']
        self._font_sizes = font_sizes or (40, 45, 50)
        self._truefonts = []

    @property
    def truefonts(self):
        if self._truefonts:
            return self._truefonts
        self._truefonts = tuple([
            ImageFont.truetype(n, s)
            for n in self._fonts
            for s in self._font_sizes
        ])
        return self._truefonts


    # 曲线噪音
    @staticmethod
    def create_noise_curve(image, color):
        curve_width = random.randint(0, 4)
        if curve_width == 0:
            return image

        w, h = image.size
        x1 = random.randint(0, int(w / 5))
        y1 = random.randint(int(h / 5), h - int(h / 5))
        for i