1、介绍
在爬虫中经常会遇到验证码识别的问题，现在的验证码大多分计算验证码、滑块验证码、识图验证码、语音验证码等四种。本文就是识图验证码，识别的是简单的验证码，要想让识别率更高，识别的更加准确就需要花很多的精力去训练自己的字体库。
识别验证码通常是这几个步骤：
（1）灰度处理
（2）二值化
（3）去除边框（如果有的话）
（4）降噪
（5）切割字符或者倾斜度矫正
（6）训练字体库
（7）识别
这6个步骤中前三个步骤是基本的，4或者5可根据实际情况选择是否需要。
经常用的库有pytesseract(识别库)、OpenCV(高级图像处理库)、imagehash（图片哈希值库）、numpy（开源的、高性能的Python数值计算库）、PIL的 Image，ImageDraw，ImageFile等。
2、实例
以某网站登录的验证码识别为例：具体过程和上述的步骤稍有不同。
首先分析一下，验证码是由4个从0到9等10个数字组成的，那么从0到9这个10个数字没有数字只有第一、第二、第三和第四等4个位置。那么计算下来共有40个数字位置，如下：
那么接下来就要对验证码图片进行降噪、分隔得到上面的图片。以这40个图片集作为基础。
对要验证的验证码图片进行降噪、分隔后获取四个类似上面的数字图片、通过和上面的比对就可以知道该验证码是什么了。
以上面验证码2837为例：
1、图片降噪
2、图片分隔
3、图片比对
通过比验证码降噪、分隔后的四个数字图片，和上面的40个数字图片进行哈希值比对，设置一个误差，max_dif：允许最大hash差值，越小越精确，最小为0。
这样四个数字图片通过比较后获取对应是数字，连起来，就是要获取的验证码。
完整代码如下：
#coding=utf-8
import os
import re
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
import time
from selenium.webdriver.common.action_chains import ActionChains
import collections
import mongoDbBase
import numpy
import imagehash
from PIL import Image,ImageFile
import datetime
class finalNews_IE:
def __init__(self,strdate,logonUrl,firstUrl,keyword_list,exportPath,codepath,codedir):
self.iniDriver()
self.db = mongoDbBase.mongoDbBase()
self.date = strdate
self.firstUrl = firstUrl
self.logonUrl = logonUrl
self.keyword_list = keyword_list
self.exportPath = exportPath
self.codedir = codedir
self.hash_code_dict ={}
for f in range(0,10):
for l in range(1,5):
file = os.path.join(codedir, "codeLibrary\code" + str(f) + '_'+str(l) + ".png")
# print(file)
hash = self.get_ImageHash(file)
self.hash_code_dict[hash]= str(f)
def iniDriver(self):
# 通过配置文件获取IEDriverServer.exe路径
IEDriverServer = "C:\Program Files\Internet Explorer\IEDriverServer.exe"
os.environ["webdriver.ie.driver"] = IEDriverServer
self.driver = webdriver.Ie(IEDriverServer)
def WriteData(self, message, fileName):
fileName = os.path.join(os.getcwd(), self.exportPath + '/' + fileName)
with open(fileName, 'a') as f:
f.write(message)
# 获取图片文件的hash值
def get_ImageHash(self,imagefile):
hash = None
if os.path.exists(imagefile):
with open(imagefile, 'rb') as fp:
hash = imagehash.average_hash(Image.open(fp))
return hash
# 点降噪
def clearNoise(self, imageFile, x=0, y=0):
if os.path.exists(imageFile):
image = Image.open(imageFile)
image = image.convert('L')
image = numpy.asarray(image)
image = (image > 135) * 255
image = Image.fromarray(image).convert('RGB')
# save_name = "D:\work\python36_crawl\Veriycode\mode_5590.png"
# image.save(save_name)
image.save(imageFile)
return image
#切割验证码
# rownum：切割行数；colnum：切割列数；dstpath：图片文件路径；img_name：要切割的图片文件
def splitimage(self, imagePath,imageFile,rownum=1, colnum=4):
img = Image.open(imageFile)
w, h = img.size
if rownum <= h and colnum <= w:
print('Original image info: %sx%s, %s, %s' % (w, h, img.format, img.mode))
print('开始处理图片切割, 请稍候...')
s = os.path.split(imageFile)
if imagePath == '':
dstpath = s[0]
fn = s[1].split('.')
basename = fn[0]
ext = fn[-1]
num = 1
rowheight = h // rownum
colwidth = w // colnum
file_list =[]
for r in range(rownum):
index = 0
for c in range(colnum):
# (left, upper, right, lower)
# box = (c * colwidth, r * rowheight, (c + 1) * colwidth, (r + 1) * rowheight)
if index < 1:
colwid = colwidth + 6
elif index < 2:
colwid = colwidth + 1
elif index < 3:
colwid = colwidth
box = (c * colwid, r * rowheight, (c + 1) * colwid, (r + 1) * rowheight)
newfile = os.path.join(imagePath, basename + '_' + str(num) + '.' + ext)
file_list.append(newfile)
img.crop(box).save(newfile, ext)
num = num + 1
index += 1
return file_list
def compare_image_with_hash(self, image_hash1,image_hash2, max_dif=0):
"""
max_dif: 允许最大hash差值, 越小越精确,最小为0
推荐使用
"""
dif = image_hash1 - image_hash2
# print(dif)
if dif < 0:
dif = -dif
if dif <= max_dif:
return True
else:
return False
# 截取验证码图片
def savePicture(self):
self.driver.get(self.logonUrl)
self.driver.maximize_window()
time.sleep(1)
self.driver.save_screenshot(self.codedir +"\Temp.png")
checkcode = self.driver.find_element_by_id("checkcode")
location = checkcode.location # 获取验证码x,y轴坐标
size = checkcode.size # 获取验证码的长宽
rangle = (int(location['x']), int(location['y']), int(location['x'] + size['width']),
int(location['y'] + size['height'])) # 写成我们需要截取的位置坐标
i = Image.open(self.codedir +"\Temp.png") # 打开截图
result = i.crop(rangle) # 使用Image的crop函数，从截图中再次截取我们需要的区域
filename = datetime.datetime.now().strftime("%M%S")
filename =self.codedir +"\Temp_code.png"
result.save(filename)
self.clearNoise(filename)
file_list = self.splitimage(self.codedir,filename)
verycode =''
for f in file_list:
imageHash = self.get_ImageHash(f)
for h,code in self.hash_code_dict.items():
flag = self.compare_image_with_hash(imageHash,h,0)
if flag:
# print(code)
verycode+=code
break
print(verycode)
self.driver.close()
def longon(self):
self.driver.get(self.logonUrl)
self.driver.maximize_window()
time.sleep(1)
self.savePicture()
accname = self.driver.find_element_by_id("username")
# accname = self.driver.find_element_by_id("//input[@id='username']")
accname.send_keys('ctrchina')
accpwd = self.driver.find_element_by_id("password")
# accpwd.send_keys('123456')
code = self.getVerycode()
checkcode = self.driver.find_element_by_name("checkcode")
checkcode.send_keys(code)
submit = self.driver.find_element_by_name("button")
submit.click()
实例补充：
# -*- coding: utf-8 -*
import sys
reload(sys)
sys.setdefaultencoding( "utf-8" )
import re
import requests
import io
import os
import json
from PIL import Image
from PIL import ImageEnhance
from bs4 import BeautifulSoup
import mdata
class Student:
def __init__(self, user,password):
self.user = str(user)
self.password = str(password)
self.s = requests.Session()
def login(self):
url = "http://202.118.31.197/ACTIONLOGON.APPPROCESS?mode=4"
res = self.s.get(url).text
imageUrl = 'http://202.118.31.197/'+re.findall('<img src="(.+?)" width="55"',res)[0]
im = Image.open(io.BytesIO(self.s.get(imageUrl).content))
enhancer = ImageEnhance.Contrast(im)
im = enhancer.enhance(7)
x,y = im.size
for i in range(y):
for j in range(x):
if (im.getpixel((j,i))!=(0,0,0)):
im.putpixel((j,i),(255,255,255))
num = [6,19,32,45]
verifyCode = ""
for i in range(4):
a = im.crop((num[i],0,num[i]+13,20))
l=[]
x,y = a.size
for i in range(y):
for j in range(x):
if (a.getpixel((j,i))==(0,0,0)):
l.append(1)
else:
l.append(0)
his=0
chrr="";
for i in mdata.data:
r=0;
for j in range(260):
if(l[j]==mdata.data[i][j]):
r+=1
if(r>his):
his=r
chrr=i
verifyCode+=chrr
# print "辅助输入验证码完毕:",verifyCode
data= {
'WebUserNO':str(self.user),
'Password':str(self.password),
'Agnomen':verifyCode,
}
url = "http://202.118.31.197/ACTIONLOGON.APPPROCESS?mode=4"
t = self.s.post(url,data=data).text
if re.findall("images/Logout2",t)==[]:
l = '[0,"'+re.findall('alert((.+?));',t)[1][1][2:-2]+'"]'+" "+self.user+" "+self.password+"\n"
# print l
# return '[0,"'+re.findall('alert((.+?));',t)[1][1][2:-2]+'"]'
return [False,l]
else:
l = '登录成功 '+re.findall('! (.+?) ',t)[0]+" "+self.user+" "+self.password+"\n"
# print l
return [True,l]
def getInfo(self):
imageUrl = 'http://202.118.31.197/ACTIONDSPUSERPHOTO.APPPROCESS'
data = self.s.get('http://202.118.31.197/ACTIONQUERYBASESTUDENTINFO.APPPROCESS?mode＝3').text #学籍信息
data = BeautifulSoup(data,"lxml")
q = data.find_all("table",attrs={'align':"left"})
a = []
for i in q[0]:
if type(i)==type(q[0]) :
for j in i :
if type(j) ==type(i):
a.append(j.text)
for i in q[1]:
if type(i)==type(q[1]) :
for j in i :
if type(j) ==type(i):
a.append(j.text)
data = {}
for i in range(1,len(a),2):
data[a[i-1]]=a[i]
# data['照片'] = io.BytesIO(self.s.get(imageUrl).content)
return json.dumps(data)
def getPic(self):
imageUrl = 'http://202.118.31.197/ACTIONDSPUSERPHOTO.APPPROCESS'
pic = Image.open(io.BytesIO(self.s.get(imageUrl).content))
return pic
def getScore(self):
score = self.s.get('http://202.118.31.197/ACTIONQUERYSTUDENTSCORE.APPPROCESS').text #成绩单
score = BeautifulSoup(score, "lxml")
q = score.find_all(attrs={'height':"36"})[0]
point = q.text
print point[point.find('平均学分绩点'):]
table = score.html.body.table
people = table.find_all(attrs={'height' : '36'})[0].string
r = table.find_all('table',attrs={'align' : 'left'})[0].find_all('tr')
subject = []
lesson = []
for i in r[0]:
if type(r[0])==type(i):
subject.append(i.string)
for i in r:
k=0
temp = {}
for j in i:
if type(r[0])==type(j):
temp[subject[k]] = j.string
k+=1
lesson.append(temp)
lesson.pop()
lesson.pop(0)
return json.dumps(lesson)
def logoff(self):
return self.s.get('http://202.118.31.197/ACTIONLOGOUT.APPPROCESS').text
if __name__ == "__main__":
a = Student(20150000,20150000)
r = a.login()
print r[1]
if r[0]:
r = json.loads(a.getScore())
for i in r:
for j in i:
print i[j],
print
q = json.loads(a.getInfo())
for i in q:
print i,q[i]
a.getPic().show()
a.logoff()
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