pytesser模块WindowsError错误解决方法

Traceback (most recent call last):
  File "E:/Code/Captcha/ChinaMobileEC/recogCaptcha.py", line 37, in <module>
    print pytesser.image_to_string(out)
  File "E:\Code\Captcha\pytesser\pytesser.py", line 36, in image_to_string
    call_tesseract(scratch_image_name, scratch_text_name_root)
  File "E:\Code\Captcha\pytesser\pytesser.py", line 25, in call_tesseract
    proc = subprocess.Popen(args)
  File "C:\Python27\lib\subprocess.py", line 710, in __init__
    errread, errwrite)
  File "C:\Python27\lib\subprocess.py", line 958, in _execute_child
    startupinfo)
WindowsError: [Error 2] 

tesseract_exe_name = 'tesseract'

def call_tesseract(input_filename, output_filename):
    """Calls external tesseract.exe on input file (restrictions on types),
    outputting output_filename+'txt'"""
    args = [tesseract_exe_name, input_filename, output_filename]
    proc = subprocess.Popen(args)
    retcode = proc.wait()
    if retcode != 0:
        errors.check_for_errors()

import os

pwd = os.path.dirname(__file__)

# 将原来的 tesseract_exe_name='tesseract' 改成绝对路径
tesseract_exe_name = os.path.join(pwd,'tesseract')