I tried running this code and it crashed my kernel (on Mac OSX 10.12.6). Do
you know why this could be?
On Wednesday, April 3, 2019 at 1:05:16 AM UTC-4, Guru Govindan wrote:
>
> Thanks a lot for your response and example. I will try today. I dont have
> much experience with cffi. So I decided to write my tesseract python
> interface with just ctypes.
> The following is my code for the same. It seems to work. So for loading
> the tesseract library it takes about 160ms and recognizing the text with
> (psm 6) takes about 140ms. These are the results with tessdata_best.
> So in order to get better performance I decided to create 100 instances of
> my class and rotate them in an array. That way my recognizing time is under
> ~140ms.
> But I definetely want to try with cffi as it is a cleaner interface to
> understand and somehow feel might be better in performance.
>
> import cv2
> import ctypes
> import ctypes.util
> from datetime import datetime
>
>
> class TesseractError(Exception):
> pass
>
> class Tesseract(object):
> _lib = None
> _api = None
>
> class TessBaseAPI(ctypes._Pointer):
> _type_ = type('_TessBaseAPI', (ctypes.Structure,), {})
>
> @classmethod
> def setup_lib(cls, lib_path=None):
> if cls._lib is not None:
> return
> if lib_path is None:
> lib_path = "/usr/local/lib/libtesseract.so.4"
> cls._lib = lib = ctypes.CDLL(lib_path)
>
> # source:
> #
> https://github.com/tesseract-ocr/tesseract/blob/95ea778745edd1cdf6ee22f9fe653b9e061d5708/src/api/capi.h
>
> lib.TessBaseAPICreate.restype = cls.TessBaseAPI
>
> lib.TessBaseAPIDelete.restype = None # void
> lib.TessBaseAPIDelete.argtypes = (
> cls.TessBaseAPI,) # handle
>
> lib.TessBaseAPIInit3.argtypes = (cls.TessBaseAPI, ctypes.c_char_p,
> ctypes.c_char_p)
>
> lib.TessBaseAPISetImage.restype = None
> lib.TessBaseAPISetImage.argtypes = (cls.TessBaseAPI,
> ctypes.c_void_p, ctypes.c_int, ctypes.c_int, ctypes.c_int, ctypes.c_int)
>
> lib.TessBaseAPISetVariable.argtypes = (cls.TessBaseAPI,
> ctypes.c_char_p, ctypes.c_char_p)
>
> lib.TessBaseAPIGetUTF8Text.restype = ctypes.c_char_p
> lib.TessBaseAPIGetUTF8Text.argtypes = (
> cls.TessBaseAPI,)
>
> def __init__(self, language='eng_best', datapath=None, lib_path=None):
> if self._lib is None:
> self.setup_lib(lib_path)
> self._api = self._lib.TessBaseAPICreate()
> print "initializing tesseract!!!!"
> if self._lib.TessBaseAPIInit3(self._api, datapath, language):
> print "Tesseract initialization failed!!"
> raise TesseractError('initialization failed')
>
> def __del__(self):
> if not self._lib or not self._api:
> return
> if not getattr(self, 'closed', False):
> self._lib.TessBaseAPIDelete(self._api)
> self.closed = True
>
> def _check_setup(self):
> if not self._lib:
> raise TesseractError('lib not configured')
> if not self._api:
> raise TesseractError('api not created')
>
> def set_image(self, imagedata, width, height,
> bytes_per_pixel, bytes_per_line=None):
> self._check_setup()
> if bytes_per_line is None:
> bytes_per_line = width * bytes_per_pixel
> print "bytes per line={}".format(bytes_per_line)
> self._lib.TessBaseAPISetImage(self._api,
> imagedata, width, height,
> bytes_per_pixel, bytes_per_line)
>
> def set_variable(self, key, val):
> self._check_setup()
> self._lib.TessBaseAPISetVariable(self._api, key, val)
>
> def get_utf8_text(self):
> self._check_setup()
> return self._lib.TessBaseAPIGetUTF8Text(self._api)
>
> def get_text(self):
> self._check_setup()
> result = self._lib.TessBaseAPIGetUTF8Text(self._api)
> if result:
> return result.decode('utf-8')
>
> def convert_to_grayscale(image_data):
> return cv2.cvtColor(image_data, cv2.COLOR_BGR2GRAY)
>
> # a method to make it look similar to tesslib.py
> def tesseract_process_image2(tess, frame_piece):
> grayscaled = len(frame_piece.frame.shape) == 2
> if not grayscaled:
> image_data = convert_to_grayscale(frame_piece.frame)
>
> height, width = frame_piece.frame.shape
> tess.set_variable("tesseract_char_whitelist", frame_piece.whitelist)
> tess.set_variable("tessedit_pageseg_mode", str(frame_piece.psm))
> # tess.set_variable("user_words_suffix", "user-data")
> # tess.set_variable("user_pattern_suffix", "user-pattern")
> tess.set_variable("image_default_resolution", "70")
> tess.set_image(frame_piece.frame.ctypes, width, height, 1)
> text = tess.get_utf8_text()
> return text.strip()
>
> class FramePiece(object):
> def __init__(self, img, whitelist):
> self.frame = img
> self.whitelist = whitelist if whitelist else
> "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890"
> self.psm = 6
>
> # overloaded method for view page
> def tesseract_process_image(tess, frame, whitelist=None):
> frame_piece = FramePiece(frame, whitelist)
> return tesseract_process_image2(tess, frame_piece)
>
> ############################### TESTING ######################
>
>
> if __name__ == '__main__':
> img = cv2.imread('/data/framecache/testing.jpg')
> height, width, depth = img.shape
> print datetime.utcnow()
> tess = Tesseract()
> print "ocr image Start:{}".format(datetime.utcnow())
> frame_piece = FramePiece(img)
> res = tesseract_process_image2(tess, frame_piece)
> print res
>
>
>
> On Tuesday, April 2, 2019 at 2:45:13 PM UTC-7, zdenop wrote:
>>
>> OK. I have more time to look at you code and I see there few problems:
>>
>> - Whitelist does not work at tesseract 4.0 (search for more details
>> in forum/issue tracker)
>> - Setting variable: there is no variable like "
>> image_default_resolution" in tesseract 4.x - you need to check return
>> value of command. Try something like this:
>>
>> # Example to set variable
>> var = "user_defined_dpi"
>> value = "250"
>> ret_val = tesseract.TessBaseAPISetVariable(api, var.encode(),
>> value.encode())
>> print(f"SetVariable for {var}={value} {'was sucessfull' if ret_val else
>> 'failed'}.")
>> # Example to get int variable
>> dpi = ffi.new('int *')
>> ret_val = tesseract.TessBaseAPIGetIntVariable(api, var.encode(), dpi)
>> print((f"Can not get int value for '{var}'.", f"{var}:
>> {dpi[0]}.")[ret_val])
>>
>>
>> - Setting data to tesseract: did you check if there in no error? Try
>> to get thresholded (binarized) image from tesseract to check that:
>>
>> thresholded_pix = tesseract.TessBaseAPIGetThresholdedImage(api)
>> if thresholded_pix == ffi.NULL:
>> print(thresholded_pix)
>> print("There is no image in tesseract api. Did you use SetImage
>> function?")
>> else:
>> filename = "thresholded_pix.png"
>> if leptonica.pixWrite(filename.encode(), thresholded_pix,
>> leptonica.IFF_PNG):
>> print("There was problem to save thresholded image to disk.")
>> else:
>> print(f"Thresholded image to disk as '{filename}'.")
>>
>>
>> - and then you will see that your usage of TessBaseAPISetImagedoes
>> not what you expect. Following code worked for my test images, but I do
>> not guarantee it will for for all types of image (RGBA, grays scale,
>> binary):
>>
>> img = cv2.imread("test.jpg", flags=cv2.IMREAD_COLOR)
>> tesseract.TessBaseAPISetImage(api,
>> ffi.cast("unsigned char*", img.ctypes.data),
>> img.shape[1], img.shape[0], img.shape[2], int(img.size/img.shape[0]))
>>
>>
>> I hope this will help you. Please share you result, especially if you
>> make this code more robust.
>>
>>
>> Zdenko
>>
>>
>> ut 2. 4. 2019 o 8:54 Zdenko Podobny <zde...@gmail.com> napísal(a):
>>
>>> My code use PIL to open image files.
>>>
>>> You need to convert cv image structure to pix or send the data to
>>> tesseract[1] with
>>> void SetImage(const unsigned char* imagedata, int width, int height, int
>>> bytes_per_pixel, int bytes_per_line)[2]
>>>
>>> [1]
>>> https://stackoverflow.com/questions/8115368/converting-cvmat-for-tesseract
>>>
>>> [2] https://github.com/tesseract-
>>>
>>> ocr/tesseract/blob/3e7144e79654d9da7a180a3c51e843afb4a77491/src/api/baseapi.h#L333
>>>
>>> If you have problem, post your code and image.
>>>
>>> Zdenko
>>>
>>>
>>> ut 2. 4. 2019 o 8:46 Guru Govindan <gurunatha...@gmail.com> napísal(a):
>>>
>>>> Hi Thanks a lot for the great post. I am trying to use cffi wrapper in
>>>> my project as the pytesseract was really slow.
>>>> I use opencv to read my image and I am trying to use your cffi setup
>>>> and initiate. But I the tesseract is not recognizing any text.
>>>>
>>>> import ctypes
>>>> import os
>>>>
>>>> import cffi
>>>>
>>>> import cv2
>>>>
>>>> tessdata = "/home/vagrant/reelz_base/shared/tessdata/"
>>>>
>>>> ffi = cffi.FFI()
>>>>
>>>> ffi.cdef("""
>>>> typedef signed char l_int8;
>>>> typedef unsigned char l_uint8;
>>>> typedef short l_int16;
>>>> typedef unsigned short l_uint16;
>>>> typedef int l_int32;
>>>> typedef unsigned int l_uint32;
>>>> typedef float l_float32;
>>>> typedef double l_float64;
>>>> typedef long long l_int64;
>>>> typedef unsigned long long l_uint64;
>>>> typedef int l_ok; /*!< return type 0 if OK, 1 on error */
>>>>
>>>>
>>>>
>>>> typedef struct TessBaseAPI TessBaseAPI;
>>>> typedef struct ETEXT_DESC ETEXT_DESC;
>>>> typedef struct TessPageIterator TessPageIterator;
>>>> typedef struct TessResultIterator TessResultIterator;
>>>> typedef int BOOL;
>>>>
>>>> typedef enum TessOcrEngineMode {
>>>> OEM_TESSERACT_ONLY = 0,
>>>> OEM_LSTM_ONLY = 1,
>>>> OEM_TESSERACT_LSTM_COMBINED = 2,
>>>> OEM_DEFAULT = 3} TessOcrEngineMode;
>>>>
>>>> typedef enum TessPageSegMode {
>>>> PSM_OSD_ONLY = 0,
>>>> PSM_AUTO_OSD = 1,
>>>> PSM_AUTO_ONLY = 2,
>>>> PSM_AUTO = 3,
>>>> PSM_SINGLE_COLUMN = 4,
>>>> PSM_SINGLE_BLOCK_VERT_TEXT = 5,
>>>> PSM_SINGLE_BLOCK = 6,
>>>> PSM_SINGLE_LINE = 7,
>>>> PSM_SINGLE_WORD = 8,
>>>> PSM_CIRCLE_WORD = 9,
>>>> PSM_SINGLE_CHAR = 10,
>>>> PSM_SPARSE_TEXT = 11,
>>>> PSM_SPARSE_TEXT_OSD = 12,
>>>> PSM_COUNT = 13} TessPageSegMode;
>>>>
>>>> typedef enum TessPageIteratorLevel {
>>>> RIL_BLOCK = 0,
>>>> RIL_PARA = 1,
>>>> RIL_TEXTLINE = 2,
>>>> RIL_WORD = 3,
>>>> RIL_SYMBOL = 4} TessPageIteratorLevel;
>>>>
>>>> TessPageIterator* TessBaseAPIAnalyseLayout(TessBaseAPI* handle);
>>>> TessPageIterator* TessResultIteratorGetPageIterator(TessResultIterator*
>>>> handle);
>>>>
>>>> BOOL TessPageIteratorNext(TessPageIterator* handle,
>>>> TessPageIteratorLevel level);
>>>> BOOL TessPageIteratorBoundingBox(const TessPageIterator* handle,
>>>> TessPageIteratorLevel level,
>>>> int* left, int* top, int* right, int*
>>>> bottom);
>>>>
>>>> const char* TessVersion();
>>>>
>>>> TessBaseAPI* TessBaseAPICreate();
>>>> void TessBaseAPIDelete(TessBaseAPI* handle);
>>>>
>>>> size_t TessBaseAPIGetOpenCLDevice(TessBaseAPI* handle, void **device);
>>>>
>>>> void TessBaseAPISetInputName( TessBaseAPI* handle, const char* name);
>>>>
>>>> const char* TessBaseAPIGetInputName(TessBaseAPI* handle);
>>>>
>>>> void TessBaseAPISetInputImage(TessBaseAPI* handle, struct Pix* pix);
>>>>
>>>> int TessBaseAPIGetSourceYResolution(TessBaseAPI* handle);
>>>>
>>>>
>>>> BOOL TessBaseAPISetVariable(TessBaseAPI* handle, const char* name,
>>>> const char* value);
>>>> BOOL TessBaseAPISetDebugVariable(TessBaseAPI* handle, const char*
>>>> name, const char* value);
>>>>
>>>> void TessBaseAPIPrintVariables( const TessBaseAPI* handle, FILE*
>>>> fp);
>>>>
>>>> BOOL TessBaseAPIPrintVariablesToFile(const TessBaseAPI* handle, const
>>>> char* filename);
>>>>
>>>> int TessBaseAPIInit1(TessBaseAPI* handle, const char* datapath, const
>>>> char* language, TessOcrEngineMode oem,
>>>> char** configs, int
>>>> configs_size);
>>>> int TessBaseAPIInit2(TessBaseAPI* handle, const char* datapath, const
>>>> char* language, TessOcrEngineMode oem);
>>>>
>>>> int TessBaseAPIInit3(TessBaseAPI* handle, const char* datapath, const
>>>> char* language);
>>>>
>>>> int TessBaseAPIInit4(TessBaseAPI* handle, const char* datapath, const
>>>> char* language, TessOcrEngineMode mode,
>>>> char** configs, int configs_size,
>>>> char** vars_vec, char** vars_values, size_t vars_vec_size,
>>>> BOOL set_only_non_debug_params);
>>>>
>>>> void TessBaseAPISetImage(TessBaseAPI* handle, const unsigned char*
>>>> imagedata, int width, int height,
>>>> int bytes_per_pixel, int
>>>> bytes_per_line);
>>>>
>>>> int TessBaseAPIRecognize(TessBaseAPI* handle, ETEXT_DESC* monitor);
>>>> TessResultIterator* TessBaseAPIGetIterator(TessBaseAPI* handle);
>>>> BOOL TessResultIteratorNext(TessResultIterator* handle,
>>>> TessPageIteratorLevel level);
>>>> char* TessResultIteratorGetUTF8Text(const TessResultIterator* handle,
>>>> TessPageIteratorLevel level);
>>>> float TessResultIteratorConfidence(const TessResultIterator* handle,
>>>> TessPageIteratorLevel level);
>>>> char* TessBaseAPIGetUTF8Text(TessBaseAPI* handle);
>>>> const char* TessResultIteratorWordFontAttributes(const
>>>> TessResultIterator* handle, BOOL* is_bold, BOOL* is_italic,
>>>> BOOL*
>>>> is_underlined, BOOL* is_monospace, BOOL* is_serif,
>>>> BOOL*
>>>> is_smallcaps, int* pointsize, int* font_id);
>>>> BOOL TessResultIteratorWordIsFromDictionary(const TessResultIterator*
>>>> handle);
>>>> BOOL TessResultIteratorWordIsNumeric(const TessResultIterator* handle);
>>>> BOOL TessResultIteratorSymbolIsSuperscript(const TessResultIterator*
>>>> handle);
>>>> BOOL TessResultIteratorSymbolIsSubscript(const TessResultIterator*
>>>> handle);
>>>> BOOL TessResultIteratorSymbolIsDropcap(const TessResultIterator*
>>>> handle);
>>>>
>>>> void TessBaseAPIEnd(TessBaseAPI* handle);
>>>> """)
>>>>
>>>> tess_libname = "/usr/local/lib/libtesseract.so.4"
>>>>
>>>> if os.path.exists(tess_libname):
>>>> tesseract = ffi.dlopen(tess_libname)
>>>>
>>>> api = None
>>>> tesseract_version = ffi.string(tesseract.TessVersion())
>>>> print('Tesseract-ocr version', tesseract_version.decode('utf-8'))
>>>> api = tesseract.TessBaseAPICreate()
>>>>
>>>> c_ubyte_p = ctypes.POINTER(ctypes.c_ubyte)
>>>>
>>>> lang="eng"
>>>> oem = tesseract.OEM_DEFAULT
>>>> tesseract.TessBaseAPIInit3(api, tessdata.encode(), lang.encode())
>>>> img = cv2.imread("/data/framecache/testing.jpg")
>>>>
>>>> tesseract.TessBaseAPISetDebugVariable(api, "tesseract_char_whitelist",
>>>> "ABCDEFGHIJKLMNOPQRSTUVWXYZ")
>>>> tesseract.TessBaseAPISetDebugVariable(api, "tessedit_pageseg_mode", "8")
>>>> tesseract.TessBaseAPISetVariable(api, "image_default_resolution", "72")
>>>>
>>>> tesseract.TessBaseAPISetImage(api, ffi.cast("unsigned char*",
>>>> img.ctypes.data), img.shape[0], img.shape[1], 1, img.shape[1])
>>>>
>>>> # tesseract.TessBaseAPIRecognize(api, ffi.NULL)
>>>>
>>>> utf8_text =
>>>> ffi.string(tesseract.TessBaseAPIGetUTF8Text(api)).decode('utf-8')
>>>> print utf8_text
>>>>
>>>>
>>>>
>>>>
>>>> On Sunday, March 24, 2019 at 10:10:36 AM UTC-7, zdenop wrote:
>>>>>
>>>>> Hi all,
>>>>>
>>>>> I publish my test / example how to use tesseract C-API in python3 via
>>>>> cffi[1].
>>>>>
>>>>> I am aware of pytesseract module, which seems to be widely used. It is
>>>>> wrapping tesseract executable, so IMO it could have some limitation e.g.
>>>>> from point of performance (it using disk operation for input and output).
>>>>>
>>>>> It is in form of jupyter notebook[3] (github is able to show it, but
>>>>> not run ;-)) so you can interactively view what is happening.
>>>>>
>>>>> My aim is not to create new tesseract python wrapper (I do not have a
>>>>> time for it, and I am not able to create nice python code as pytesseract
>>>>> has :-) ) so it is not robust: I just did it on windows 64 bit, but IMO
>>>>> is
>>>>> should be possible with small modification to use in Linux and Mac. If
>>>>> needed I can add 32bit windows libs...
>>>>>
>>>>> Personally I would like have python tesseract and leptonica module
>>>>> using directly its API... I know that James Barlow already started to
>>>>> wrapping leptonica, but it is (not yet?) available as independent module
>>>>> (it is part of OCRmyPDF).
>>>>>
>>>>> Anyway I hope this will help somebody.
>>>>>
>>>>> [1] https://github.com/zdenop/SimpleTesseractPythonWrapper
>>>>> [2] https://pypi.org/project/pytesseract/
>>>>> [3]
>>>>> https://github.com/zdenop/SimpleTesseractPythonWrapper/blob/master/SimpleTesseractPythonWrapper.ipynb
>>>>>
>>>>> [4] https://github.com/jbarlow83/OCRmyPDF/tree/master/src/ocrmypdf/lib
>>>>>
>>>>>
>>>>> Zdenko
>>>>>
>>>> --
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>>>>
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>>>> For more options, visit https://groups.google.com/d/optout.
>>>>
>>>
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