Exception on using ctypes with tesserac-ocr TessPageIteratorBoundingBox

问题

import ctypes
import os
os.putenv("PATH", r'C:\Program Files\Tesseract-OCR')
os.environ["TESSDATA_PREFIX"] = r'C:\Program Files\Tesseract-OCR\tessdata'

liblept = ctypes.cdll.LoadLibrary('liblept-5.dll')
pix = liblept.pixRead('test.png'.encode())
print(pix)

tesseractLib = ctypes.cdll.LoadLibrary('libtesseract-5.dll')

tesseractHandle = tesseractLib.TessBaseAPICreate()

tesseractLib.TessBaseAPIInit3(tesseractHandle, '.', 'eng')

tesseractLib.TessBaseAPISetImage2(tesseractHandle, pix)

# text_out = tesseractLib.TessBaseAPIGetUTF8Text(tesseractHandle)
# print(ctypes.string_at(text_out))

tessPageIterator = tesseractLib.TessResultIteratorGetPageIterator(tesseractHandle)
iteratorLevel = 3  # RIL_BLOCK,  RIL_PARA,  RIL_TEXTLINE,  RIL_WORD,  RIL_SYMBOL
tesseractLib.TessPageIteratorBoundingBox(tessPageIterator, iteratorLevel, ctypes.c_int(0), ctypes.c_int(0), ctypes.c_int(0), ctypes.c_int(0))

I got exceptions :

Traceback (most recent call last):
  File "D:\BaiduYunDownload\programming\Python\CtypesOCR.py", line 25, in <module>
    tesseractLib.TessPageIteratorBoundingBox(tessPageIterator, iteratorLevel, ctypes.c_int(0), ctypes.c_int(0), ctypes.c_int(0), ctypes.c_int(0))
OSError: exception: access violation reading 0x00000018

So what's wrong ? The aim of this program is to get bounding rectangle of each word. I know projects like tesserocr and PyOCR

P.S. Specifying the required argument types (function prototypes) for the DLL functions doesn't matter here. One could uncoment the commented lines and comment the last three lines to test it. I posted the question before , and it was closed for this reason

来源：https://stackoverflow.com/questions/60188293/exception-on-using-ctypes-with-tesserac-ocr-tesspageiteratorboundingbox

标签

python

c++

tesseract

ctypes