一、pytesseract介紹
1、pytesseract說明
pytesseract最新版本0.1.6,網址:https://pypi.python.org/pypi/pytesseract
Python-tesseract is a wrapper for google's Tesseract-OCR
( http://code.google.com/p/tesseract-ocr/ ). It is also useful as a
stand-alone invocation script to tesseract, as it can read all image types
supported by the Python Imaging Library, including jpeg, png, gif, bmp, tiff,
and others, whereas tesseract-ocr by default only supports tiff and bmp.
Additionally, if used as a script, Python-tesseract will print the recognized
text in stead of writing it to a file. Support for confidence estimates and
bounding box data is planned for future releases.
翻譯一下大意:
a、Python-tesseract是一個基于google's Tesseract-OCR的獨立封裝包;
b、Python-tesseract功能是識別圖片文件中文字,并作為返回參數返回識別結果;
c、Python-tesseract默認支持tiff、bmp格式圖片,只有在安裝PIL之后,才能支持jpeg、gif、png等其他圖片格式;
2、pytesseract安裝
INSTALLATION:
Prerequisites:
* Python-tesseract requires python 2.5 or later or python 3.
* You will need the Python Imaging Library (PIL). Under Debian/Ubuntu, this is
the package "python-imaging" or "python3-imaging" for python3.
* Install google tesseract-ocr from http://code.google.com/p/tesseract-ocr/ .
You must be able to invoke the tesseract command as "tesseract". If this
isn't the case, for example because tesseract isn't in your PATH, you will
have to change the "tesseract_cmd" variable at the top of 'tesseract.py'.
Under Debian/Ubuntu you can use the package "tesseract-ocr".
Installing via pip:
See the [pytesseract package page](https://pypi.python.org/pypi/pytesseract)
```
$> sudo pip install pytesseract
翻譯一下:
a、Python-tesseract支持python2.5及更高版本;
b、Python-tesseract需要安裝PIL(Python Imaging Library) ,來支持更多的圖片格式;
c、Python-tesseract需要安裝tesseract-ocr安裝包。
綜上,Pytesseract原理:
1、上一篇博文中提到,執行命令行 tesseract.exe 1.png output -l eng ,可以識別1.png中文字,并把識別結果輸出到output.txt中;
2、Pytesseract對上述過程進行了二次封裝,自動調用tesseract.exe,并讀取output.txt文件的內容,作為函數的返回值進行返回。
二、pytesseract使用
USAGE:
```
> try:
> import Image
> except ImportError:
> from PIL import Image
> import pytesseract
> print(pytesseract.image_to_string(Image.open('test.png')))
> print(pytesseract.image_to_string(Image.open('test-european.jpg'), lang='fra'))
可以看到:
1、核心代碼就是image_to_string函數,該函數還支持-l eng 參數,支持-psm 參數。
用法:
image_to_string(Image.open('test.png'),lang="eng" config="-psm 7")
2、pytesseract里調用了image,所以才需要PIL,其實tesseract.exe本身是支持jpeg、png等圖片格式的。
實例代碼,識別某公共網站的驗證碼(大家千萬別干壞事啊,思慮再三,最后還是隱掉網站域名,大家去找別的網站試試吧……):
#-*-coding=utf-8-*-
__author__='zhongtang'
import urllib
import urllib2
import cookielib
import math
import random
import time
import os
import htmltool
from pytesseract import *
from PIL import Image
from PIL import ImageEnhance
import re
class orclnypcg:
def __init__(self):
self.baseUrl='http://jbywcg.****.com.cn'
self.ht=htmltool.htmltool()
self.curPath=self.ht.getPyFileDir()
self.authCode=''
def initUrllib2(self):
try:
cookie = cookielib.CookieJar()
cookieHandLer = urllib2.HTTPCookieProcessor(cookie)
httpHandLer=urllib2.HTTPHandler(debuglevel=0)
httpsHandLer=urllib2.HTTPSHandler(debuglevel=0)
except:
raise
else:
opener = urllib2.build_opener(cookieHandLer,httpHandLer,httpsHandLer)
opener.addheaders = [('User-Agent','Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11')]
urllib2.install_opener(opener)
def urllib2Navigate(self,url,data={}): #定義連接函數,有超時重連功能
tryTimes = 0
while True:
if (tryTimes>20):
print u"多次嘗試仍無法鏈接網絡,程序終止"
break
try:
if (data=={}):
req = urllib2.Request(url)
else:
req = urllib2.Request(url,urllib.urlencode(data))
response =urllib2.urlopen(req)
bodydata = response.read()
headerdata = response.info()
if headerdata.get('Content-Encoding')=='gzip':
rdata = StringIO.StringIO(bodydata)
gz = gzip.GzipFile(fileobj=rdata)
bodydata = gz.read()
gz.close()
tryTimes = tryTimes +1
except urllib2.HTTPError, e:
print 'HTTPError[%s]\n' %e.code
except urllib2.URLError, e:
print 'URLError[%s]\n' %e.reason
except socket.error:
print u"連接失敗,嘗試重新連接"
else:
break
return bodydata,headerdata
def randomCodeOcr(self,filename):
image = Image.open(filename)
#使用ImageEnhance可以增強圖片的識別率
#enhancer = ImageEnhance.Contrast(image)
#enhancer = enhancer.enhance(4)
image = image.convert('L')
ltext = ''
ltext= image_to_string(image)
#去掉非法字符,只保留字母數字
ltext=re.sub("\W", "", ltext)
print u'[%s]識別到驗證碼:[%s]!!!' %(filename,ltext)
image.save(filename)
#print ltext
return ltext
def getRandomCode(self):
#開始獲取驗證碼
#http://jbywcg.****.com.cn/CommonPage/Code.aspx?0.9409255818463862
i = 0
while ( i<=100):
i += 1
#拼接驗證碼Url
randomUrlNew='%s/CommonPage/Code.aspx?%s' %(self.baseUrl,random.random())
#拼接驗證碼本地文件名
filename= '%s.png' %(i)
filename= os.path.join(self.curPath,filename)
jpgdata,jpgheader = self.urllib2Navigate(randomUrlNew)
if len(jpgdata)<= 0 :
print u'獲取驗證碼出錯!\n'
return False
f = open(filename, 'wb')
f.write(jpgdata)
#print u"保存圖片:",fileName
f.close()
self.authCode = self.randomCodeOcr(filename)
#主程序開始
orcln=orclnypcg()
orcln.initUrllib2()
orcln.getRandomCode()
三、pytesseract代碼優化
上述程序在windows平臺運行時,會發現有黑色的控制臺窗口一閃而過的畫面,不太友好。
略微修改了pytesseract.py(C:\Python27\Lib\site-packages\pytesseract目錄下),把上述過程進行了隱藏。
# modified by zhongtang hide console window
# new code
IS_WIN32 = 'win32' in str(sys.platform).lower()
if IS_WIN32:
?? startupinfo = subprocess.STARTUPINFO()
?? startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
?? startupinfo.wShowWindow = subprocess.SW_HIDE
?? proc = subprocess.Popen(command,
??????? stderr=subprocess.PIPE,startupinfo=startupinfo)
'''
# old code
proc = subprocess.Popen(command,
?? stderr=subprocess.PIPE)
'''
# modified end
為了方便初學者,把pytesseract.py也貼出來,高手自行忽略。
#!/usr/bin/env python
'''
Python-tesseract is an optical character recognition (OCR) tool for python.
That is, it will recognize and "read" the text embedded in images.
Python-tesseract is a wrapper for google's Tesseract-OCR
( http://code.google.com/p/tesseract-ocr/ ). It is also useful as a
stand-alone invocation script to tesseract, as it can read all image types
supported by the Python Imaging Library, including jpeg, png, gif, bmp, tiff,
and others, whereas tesseract-ocr by default only supports tiff and bmp.
Additionally, if used as a script, Python-tesseract will print the recognized
text in stead of writing it to a file. Support for confidence estimates and
bounding box data is planned for future releases.
USAGE:
```
> try:
> import Image
> except ImportError:
> from PIL import Image
> import pytesseract
> print(pytesseract.image_to_string(Image.open('test.png')))
> print(pytesseract.image_to_string(Image.open('test-european.jpg'), lang='fra'))
```
INSTALLATION:
Prerequisites:
* Python-tesseract requires python 2.5 or later or python 3.
* You will need the Python Imaging Library (PIL). Under Debian/Ubuntu, this is
the package "python-imaging" or "python3-imaging" for python3.
* Install google tesseract-ocr from http://code.google.com/p/tesseract-ocr/ .
You must be able to invoke the tesseract command as "tesseract". If this
isn't the case, for example because tesseract isn't in your PATH, you will
have to change the "tesseract_cmd" variable at the top of 'tesseract.py'.
Under Debian/Ubuntu you can use the package "tesseract-ocr".
Installing via pip:
See the [pytesseract package page](https://pypi.python.org/pypi/pytesseract)
$> sudo pip install pytesseract
Installing from source:
$> git clone git@github.com:madmaze/pytesseract.git
$> sudo python setup.py install
LICENSE:
Python-tesseract is released under the GPL v3.
CONTRIBUTERS:
- Originally written by [Samuel Hoffstaetter](https://github.com/hoffstaetter)
- [Juarez Bochi](https://github.com/jbochi)
- [Matthias Lee](https://github.com/madmaze)
- [Lars Kistner](https://github.com/Sr4l)
'''
# CHANGE THIS IF TESSERACT IS NOT IN YOUR PATH, OR IS NAMED DIFFERENTLY
tesseract_cmd = 'tesseract'
try:
import Image
except ImportError:
from PIL import Image
import subprocess
import sys
import tempfile
import os
import shlex
__all__ = ['image_to_string']
def run_tesseract(input_filename, output_filename_base, lang=None, boxes=False, config=None):
'''
runs the command:
`tesseract_cmd` `input_filename` `output_filename_base`
returns the exit status of tesseract, as well as tesseract's stderr output
'''
command = [tesseract_cmd, input_filename, output_filename_base]
if lang is not None:
command += ['-l', lang]
if boxes:
command += ['batch.nochop', 'makebox']
if config:
command += shlex.split(config)
# modified by zhongtang hide console window
# new code
IS_WIN32 = 'win32' in str(sys.platform).lower()
if IS_WIN32:
startupinfo = subprocess.STARTUPINFO()
startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
startupinfo.wShowWindow = subprocess.SW_HIDE
proc = subprocess.Popen(command,
stderr=subprocess.PIPE,startupinfo=startupinfo)
'''
# old code
proc = subprocess.Popen(command,
stderr=subprocess.PIPE)
'''
# modified end
return (proc.wait(), proc.stderr.read())
def cleanup(filename):
''' tries to remove the given filename. Ignores non-existent files '''
try:
os.remove(filename)
except OSError:
pass
def get_errors(error_string):
'''
returns all lines in the error_string that start with the string "error"
'''
lines = error_string.splitlines()
error_lines = tuple(line for line in lines if line.find('Error') >= 0)
if len(error_lines) > 0:
return '\n'.join(error_lines)
else:
return error_string.strip()
def tempnam():
''' returns a temporary file-name '''
tmpfile = tempfile.NamedTemporaryFile(prefix="tess_")
return tmpfile.name
class TesseractError(Exception):
def __init__(self, status, message):
self.status = status
self.message = message
self.args = (status, message)
def image_to_string(image, lang=None, boxes=False, config=None):
'''
Runs tesseract on the specified image. First, the image is written to disk,
and then the tesseract command is run on the image. Resseract's result is
read, and the temporary files are erased.
also supports boxes and config.
if boxes=True
"batch.nochop makebox" gets added to the tesseract call
if config is set, the config gets appended to the command.
ex: config="-psm 6"
'''
if len(image.split()) == 4:
# In case we have 4 channels, lets discard the Alpha.
# Kind of a hack, should fix in the future some time.
r, g, b, a = image.split()
image = Image.merge("RGB", (r, g, b))
input_file_name = '%s.bmp' % tempnam()
output_file_name_base = tempnam()
if not boxes:
output_file_name = '%s.txt' % output_file_name_base
else:
output_file_name = '%s.box' % output_file_name_base
try:
image.save(input_file_name)
status, error_string = run_tesseract(input_file_name,
output_file_name_base,
lang=lang,
boxes=boxes,
config=config)
if status:
#print 'test' , status,error_string
errors = get_errors(error_string)
raise TesseractError(status, errors)
f = open(output_file_name)
try:
return f.read().strip()
finally:
f.close()
finally:
cleanup(input_file_name)
cleanup(output_file_name)
def main():
if len(sys.argv) == 2:
filename = sys.argv[1]
try:
image = Image.open(filename)
if len(image.split()) == 4:
# In case we have 4 channels, lets discard the Alpha.
# Kind of a hack, should fix in the future some time.
r, g, b, a = image.split()
image = Image.merge("RGB", (r, g, b))
except IOError:
sys.stderr.write('ERROR: Could not open file "%s"\n' % filename)
exit(1)
print(image_to_string(image))
elif len(sys.argv) == 4 and sys.argv[1] == '-l':
lang = sys.argv[2]
filename = sys.argv[3]
try:
image = Image.open(filename)
except IOError:
sys.stderr.write('ERROR: Could not open file "%s"\n' % filename)
exit(1)
print(image_to_string(image, lang=lang))
else:
sys.stderr.write('Usage: python pytesseract.py [-l language] input_file\n')
exit(2)
if __name__ == '__main__':
main()
以上……
以上這篇python下調用pytesseract識別某網站驗證碼的實現方法就是小編分享給大家的全部內容了,希望能給大家一個參考,也希望大家多多支持腳本之家。
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