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 <gurunathan.govin...@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
>>>
>> --
>> You received this message because you are subscribed to the Google Groups
>> "tesseract-ocr" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to tesseract-ocr+unsubscr...@googlegroups.com.
>> To post to this group, send email to tesseract-ocr@googlegroups.com.
>> Visit this group at https://groups.google.com/group/tesseract-ocr.
>> To view this discussion on the web visit
>> https://groups.google.com/d/msgid/tesseract-ocr/d6253a61-d796-4cce-8412-f2cc61e83000%40googlegroups.com
>> <https://groups.google.com/d/msgid/tesseract-ocr/d6253a61-d796-4cce-8412-f2cc61e83000%40googlegroups.com?utm_medium=email&utm_source=footer>
>> .
>> For more options, visit https://groups.google.com/d/optout.
>>
>
--
You received this message because you are subscribed to the Google Groups
"tesseract-ocr" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to tesseract-ocr+unsubscr...@googlegroups.com.
To post to this group, send email to tesseract-ocr@googlegroups.com.
Visit this group at https://groups.google.com/group/tesseract-ocr.
To view this discussion on the web visit
https://groups.google.com/d/msgid/tesseract-ocr/CAJbzG8wJdCzMJmXL5kOLpKprTR%3DBOva_PL%3Dze10z1gr0EXV3%2BQ%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.
