How to recognize data not filename using ctypes and tesseract 3.0.2?

问题

I write a snippet using ctypes and tesseract 3.0.2 referring to the example:

import ctypes
from PIL import Image


libname = '/opt/tesseract/lib/libtesseract.so.3.0.2'
tesseract = ctypes.cdll.LoadLibrary(libname)
api = tesseract.TessBaseAPICreate()

rc = tesseract.TessBaseAPIInit3(api, "", 'eng')
filename = '/opt/ddl.ddl.exp654.png'

text_out = tesseract.TessBaseAPIProcessPages(api, filename, None, 0)
result_text = ctypes.string_at(text_out)
print result_text

It passes filename as a parameter, I have no idea to call which method in API to pass the raw data like:

tesseract.TessBaseAPIWhichMethod(api, open(filename).read())

回答1:

I can't say for sure but I don't think you can pass complex python objects to that specific API, it won't know how to handle them. Your best bet would to be to look at a wrapper like http://code.google.com/p/python-tesseract/ which will allow you to use file buffers

import tesseract
api = tesseract.TessBaseAPI()
api.Init(".","eng",tesseract.OEM_DEFAULT)
api.SetVariable("tessedit_char_whitelist", "0123456789abcdefghijklmnopqrstuvwxyz")
api.SetPageSegMode(tesseract.PSM_AUTO)

mImgFile = "eurotext.jpg"
mBuffer=open(mImgFile,"rb").read()
result = tesseract.ProcessPagesBuffer(mBuffer,len(mBuffer),api) #YAY for buffers.
print "result(ProcessPagesBuffer)=",result

Edit

http://code.google.com/p/python-tesseract/source/browse/python-tesseract-0.7.4/debian/python-tesseract/usr/share/pyshared/tesseract.py might provide you with the insight that you need.

...

Acutally if you don't mind what happens when you replace

text_out = tesseract.TessBaseAPIProcessPages(api, filename, None, 0)

with

text_out = tesseract.ProcessPagesBuffer(mBuffer,len(mBuffer),api)

来源：https://stackoverflow.com/questions/13150937/how-to-recognize-data-not-filename-using-ctypes-and-tesseract-3-0-2