Tesseract OCR simple example

Question

Hi Can you anyone give me a simple example of testing Tesseract OCR preferably in C   I tried the demo found here  I download the English dataset and unzipped in C drive  and modified the code as followings   string path     C  pic mytext jpg   Bitmap image   new Bitmap path   Tesseract ocr   new Tesseract    ocr SetVariable  tessedit char whitelist    0123456789       If digit only ocr Init   C  tessdata     eng   false      To use correct tessdata List lt tessnet2 Word gt  result   ocr DoOCR image  Rectangle Empty   foreach  tessnet2 Word word in result      Console WriteLine   0     1    word Confidence  word Text     Unfortunately the code doesn t work  the program dies at  ocr Init      line  I couldn t even get an exception even using try-catch   I was able to run the vietocr  but that is a very large project for me to follow  i need a simple example like above    Thanks

User · Answer

Ok  I found the solution here tessnet2 fails to load the Ans given by Adam Apparently i was using wrong version of tessdata  I was following the the source page instruction intuitively and that caused the problem  it says  Quick Tessnet2 usage  Download binary here  add a reference of the assembly Tessnet2 dll to your  NET project   Download language data definition file here and put it in tessdata directory  Tessdata directory and your exe must be in the same directory     After you download the binary  when you follow the link to download the language file  there are many language files  but none of them are right version  you need to select all version and go to next page for correct version  tesseract-2 00 eng   They should either update download binary link to version 3 or put the the version 2 language file on the first page  Or at least bold mention the fact that this version issue is a big deal  Anyway I found it  Thanks everyone

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I had same problem  now its resolved  I have tesseract2  under this folders for 32 bit and 64 bit  I copied files 64 bit folder as my system is 64 bit  to main folder   Tesseract2   and under bin Debug folder  Now my solution is working fine

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This worked for me  I had 3-4 more PDF to Text extractor and if one doesnot work the other one will     tesseract in particular this code can be used on Windows 7  8  Server 2008   Hope this is helpful to you      do              Sleep or Pause the Thread for 1 sec  if service is running too fast        Thread Sleep millisecondsTimeout  1000       Guid tempGuid   ToSeqGuid        string newFileName   tempGuid ToString   Split  -   0       string outputFileName   appPath      pdf2png      fileNameithoutExtension    -    newFileName                                 png       extractor SaveCurrentImageToFile outputFileName  ImageFormat Png          Create text file here using Tesseract     foreach  var file in Directory GetFiles appPath      pdf2png                  try                       var pngFileName   Path GetFileNameWithoutExtension file               string   myArguments                                   C tesseract    file                        appPath      png2text      pngFileName                    C for closing process automatically whent completes             string strParam   String Join      myArguments                var myCmdProcess   new Process                var theProcess   new ProcessStartInfo  cmd exe   strParam                                CreateNoWindow   true                  UseShellExecute   false                  RedirectStandardOutput   true                  RedirectStandardError   true                  WindowStyle   ProcessWindowStyle Minimized                   Keep the cmd exe window minimized             myCmdProcess StartInfo   theProcess              myCmdProcess Exited    myCmdProcess Exited              myCmdProcess Start                   if  process                                                   MessageBox Show  cmd exe process started      Environment NewLine                                    Process Name      myCmdProcess ProcessName                                   Environment NewLine     Process Id      myCmdProcess Id                                   Environment NewLine    process Handle                                      myCmdProcess Handle                                      Process EnterDebugMode                      ShowWindow hWnd  process Handle  nCmdShow  2                                      MessageBox Show  After EnterDebugMode   cmd exe process Exited                                      Environment NewLine                                    Process Name      myCmdProcess ProcessName                                   Environment NewLine     Process Id      myCmdProcess Id                                   Environment NewLine    process Handle                                      myCmdProcess Handle                                      myCmdProcess WaitForExit 60000                                      MessageBox Show  After WaitForExit   cmd exe process Exited                                      Environment NewLine                                    Process Name      myCmdProcess ProcessName                                   Environment NewLine     Process Id      myCmdProcess Id                                   Environment NewLine    process Handle                                      myCmdProcess Handle                                      myCmdProcess Refresh                    Process LeaveDebugMode                      myCmdProcess Dispose                                       MessageBox Show  After LeaveDebugMode   cmd exe process Exited                                      Environment NewLine                                                    process Kill                   Waits for the process to complete task and exites automatically             Thread Sleep millisecondsTimeout  1000                   This works fine in Windows 7 Environment  and not in Windows 8                Try following code block                Check  if process is not comletey exited              if   myCmdProcess HasExited                                  process WaitForExit 2000      Try to wait for exit 2 more seconds                                    MessageBox Show   Process of cmd exe was exited by WaitForExit    Method                                     Environment NewLine                                      try                                          If not  then Kill the process                     myCmdProcess Kill                          myCmdProcess Dispose                          if   myCmdProcess HasExited                                                    myCmdProcess Kill                                                 MessageBox Show   Process of cmd exe exited   Killed   successfully                                         Environment NewLine                                     catch  System ComponentModel Win32Exception ex                                        MessageBox Show                            Exception  System ComponentModel Win32Exception                             ex ErrorCode   Environment NewLine                                     catch  NotSupportedException notSupporEx                                        MessageBox Show   Exception  NotSupportedException                                         notSupporEx Message                                       Environment NewLine                                     catch  InvalidOperationException invalidOperation                                        MessageBox Show                            Exception  InvalidOperationException                             invalidOperation Message   Environment NewLine                       foreach                           var textFile in Directory GetFiles appPath      png2text      txt                               SearchOption AllDirectories                                                 loggingInfo    textFile                                            In Reading Text from generated text file by Tesseract                                            Environment NewLine                          strBldr Append File ReadAllText textFile                                                 Delete text file after reading text here                     Directory GetFiles appPath      pdf2png   ToList   ForEach File Delete                       Directory GetFiles appPath      png2text   ToList   ForEach File Delete                                                     catch  Exception exception                        MessageBox Show                    Cought Exception in Generating image do     while      function                     Environment NewLine   exception Message   Environment NewLine                          Delete png image here     Directory GetFiles appPath      pdf2png   ToList   ForEach File Delete       Thread Sleep millisecondsTimeout  1000          Read text from text file here     foreach  var textFile in Directory GetFiles appPath      png2text      txt           SearchOption AllDirectories                 loggingInfo    textFile                            In Reading Text from generated text file by Tesseract                            Environment NewLine          strBldr Append File ReadAllText textFile                 Delete text file after reading text here     Directory GetFiles appPath      png2text   ToList   ForEach File Delete     while  extractor GetNextImage        Advance image enumeration

User · Answer

In my case I had all these worked except for the correct character recognition    But you need to consider these few things    Use correct tessnet2 library use correct tessdata language version tessdata should be somewhere out of your application folder where you can put in full path in the init parameter  use ocr Init   c  tessdata    eng   true   Debugging will cause you headache  Then you need to update your app config use this   I can t put the xml code here  give me your email i will email it to you    hope that this helps

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Try updating the line to   ocr Init   C      eng   false      the path here should be the parent folder of tessdata

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A simple example of testing Tesseract OCR in C        public static string GetText Bitmap imgsource                var ocrtext   string Empty          using  var engine   new TesseractEngine     tessdata    eng   EngineMode Default                         using  var img   PixConverter ToPix imgsource                                 using  var page   engine Process img                                         ocrtext   page GetText                                                       return ocrtext          Info  The tessdata folder must exist in the repository  bin Debug

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Here s a great working example project  Tesseract OCR Sample  Visual Studio  with Leptonica Preprocessing Tesseract OCR Sample  Visual Studio  with Leptonica Preprocessing  Tesseract OCR 3 02 02 API can be confusing  so this guides you through including the Tesseract and Leptonica dll into a Visual Studio C   Project  and provides a sample file which takes an image path to preprocess and OCR  The preprocessing script in Leptonica converts the input image into black and white book-like text   Setup  To include this in your own projects  you will need to reference the header files and lib and copy the tessdata folders and dlls   Copy the tesseract-include folder to the root folder of your project  Now Click on your project in Visual Studio Solution Explorer  and go to Project Properties   VC   Directories Include Directories      tesseract-include tesseract    tesseract-include leptonica   IncludePath  C C   Preprocessor Preprocessor Definitions    CRT SECURE NO WARNINGS   PreprocessorDefinitions  C C   Linker Input Additional Dependencies      tesseract-include libtesseract302 lib    tesseract-include liblept168 lib   AdditionalDependencies  Now you can include headers in your project s file   include   include   Now copy the two dll files in tesseract-include and the tessdata folder in Debug to the Output Directory of your project   When you initialize tesseract  you need to specify the location of the parent folder   important  of the tessdata folder if it is not already the current directory of your executable file  You can copy my script  which assumes tessdata is installed in the executable s folder   tesseract  TessBaseAPI  api   new tesseract  TessBaseAPI    api- Init  D  tessdataParentFolder        Sample  You can compile the provided sample  which takes one command line argument of the image path to use  The preprocess   function uses Leptonica to create a black and white book-like copy of the image which makes tesseract work with 90  accuracy  The ocr   function shows the functionality of the Tesseract API to return a string output  The toClipboard   can be used to save text to clipboard on Windows  You can copy these into your own projects

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I was able to get it to work by following these instructions    Download the sample code  Unzip it to a new location Open   tesseract-samples-master src Tesseract Samples sln  I used Visual Studio 2017  Install the Tesseract NuGet package for that project  or uninstall reinstall as I had to   Uncomment the last two meaningful lines in Tesseract Samples Program cs  Console Write  Press any key to continue           Console ReadKey true   Run  hit F5  You should get this windows console output

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