AutoPreprocess(OcrAutoPreprocessPageCommand,OcrProgressCallback) Method

Summary

Perform auto image processing clean up on all the pages in the OCR document to enhance the quality of the pages before starting its recognition.

Syntax

Objective-C

C++/CLI

Java

Python

public void AutoPreprocess( 
   OcrAutoPreprocessPageCommand command, 
   OcrProgressCallback callback 
)

- (BOOL)autoPreprocessPages:(LTOcrAutoPreprocessPageCommand)command 
                   progress:(nullable LTOcrProgressHandler)progressHandler 
                      error:(NSError **)error

public void autoPreprocess(OcrAutoPreprocessPageCommand command, 
                           OcrProgressListener callback)

void AutoPreprocess(  
   OcrAutoPreprocessPageCommand command, 
   OcrProgressCallback^ callback 
)

def AutoPreprocess(self,callback):

Parameters

command
The preprocessing command to perform.

callback
Optional callback to show operation progress.

Remarks

This method will iterate through all the pages in this OCR document and run IOcrPage.AutoPreprocess on each page.

You can use this method to deskew, rotate or invert the image according to command. By performing auto pre-processing on the page, you can improve the image quality of draft mode faxes.

You can use the OcrProgressCallback to show the operation progress or to abort it. For more information and an example, refer to OcrProgressCallback.

You should call this method prior to calling Recognize.

To perform auto-preprocessing to a range of pages in the OCR document use AutoPreprocess(OcrAutoPreprocessPageCommand command, int firstPageIndex, int lastPageIndex, OcrProgressCallback callback).

This member only works with memory-based documents and will throw an exception otherwise. For more information, refer to IOcrDocumentManager.CreateDocument and Programming with the LEADTOOLS .NET OCR.

Example

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Ocr; 
using Leadtools.Document.Writer; 
using Leadtools.Forms.Common; 
using Leadtools.ImageProcessing.Core; 
 
public void PageCollectionExamples() 
{ 
   // For this example, we need a multi-page TIF file. 
   // Create a muti-page TIF from Ocr1.tif, Ocr2.tif, Ocr3.tif and Ocr4.tif 
   string tifFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr.tif"); 
   if (File.Exists(tifFileName)) 
      File.Delete(tifFileName); 
 
   using (RasterCodecs codecs = new RasterCodecs()) 
   { 
      for (int i = 0; i < 4; i++) 
      { 
         string pageFileName = Path.Combine(LEAD_VARS.ImagesDir, string.Format("Ocr{0}.tif", i + 1)); 
         using (RasterImage image = codecs.Load(pageFileName)) 
            codecs.Save(image, tifFileName, RasterImageFormat.CcittGroup4, 1, 1, 1, -1, CodecsSavePageMode.Append); 
      } 
   } 
 
   string pdfFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr.pdf"); 
 
   // Create an instance of the engine 
   using (IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD)) 
   { 
      // Start the engine using default parameters 
      ocrEngine.Startup(null, null, null, LEAD_VARS.OcrLEADRuntimeDir); 
 
      // Create an OCR document 
      using (IOcrDocument ocrDocument = ocrEngine.DocumentManager.CreateDocument()) 
      { 
         // Load all the pages of the multi-page tif file we created into the form 
         ocrDocument.Pages.AddPages(tifFileName, 1, -1, null); 
         Console.WriteLine("{0} pages added to the document", ocrDocument.Pages.Count); 
 
         // Auto-zone 
         ocrDocument.Pages.AutoZone(null); 
 
         // Recognize 
         ocrDocument.Pages.Recognize(null); 
 
         // Save 
         ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, null); 
      } 
 
      // Shutdown the engine 
      // Note: calling Dispose will also automatically shutdown the engine if it has been started 
      ocrEngine.Shutdown(); 
   } 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
   public const string OcrLEADRuntimeDir = @"C:\LEADTOOLS22\Bin\Common\OcrLEADRuntime"; 
}