ImageGear PDF v25.2 - Updated
Migrating from the Recognition Component to the OCR Component
Getting Started > Migrating from the Recognition Component to the OCR Component

In ImageGear .NET v25, we’re introducing a new OCR component and removing the old Recognition component. If you’re upgrading to v25 or later from v24.x or earlier and use the Recognition component, then there are some steps you’ll need to take to migrate your code to use the new OCR component.

Mapping Recognition API to OCR API

The tables below delineate the OCR component API equivalents, where applicable.

Namespaces

ImageGear Recognition

ImageGear OCR

ImageGear.Recognition

ImageGear.OCR

Classes

ImageGear Recognition

ImageGear OCR

ImGearRecognition

ImGearOCR

ImGearRecAsianSettings 

Not implemented

ImGearRecCheckWordEventArgs 

Not implemented

ImGearRecCodePageCollection 

Not implemented

ImGearRecDocument 

Not implemented

ImGearRecImage 

ImGearOCRImage

ImGearRecLetter 

ImGearOCRLetter

ImGearRecModuleCollection 

Not implemented

ImGearRecModuleSettings 

Not implemented

ImGearRecMORSettings 

Not implemented

ImGearRecOutputFormatCollection 

Not implemented

ImGearRecOutputManager 

Not implemented

ImGearRecPage 

ImGearOCRPage

ImGearRecPDFOutputOptions 

ImGearOCRPDFOutputOptions

ImGearRecPreprocessingSettings 

ImGearOCRPreprocessingSettings

ImGearRecProgressEventArgs 

Not implemented

ImGearRecRecognitionLanguageEnabled 

ImGearOCRLanguageEnabled

ImGearRecRecognitionSettings 

ImGearOCRSettings

ImGearRecSettingsCollectionObjectBase 

Not implemented

ImGearRecStatistics 

Not implemented

ImGearRecUDItem 

Not implemented

ImGearRecUserDictionary 

ImGearOCRDictionary

ImGearRecZone

ImGearOCRZone

ImGearRecZoneCollection

ImGearOCRZoneCollection

Enumerations

ImGearRecCheckWordOpinion 

Not implemented

ImGearRecDecompositionMethod 

Not implemented

ImGearRecDeskewMode 

ImGearOCRDeskewMode

ImGearRecDirectTextFormat 

Not implemented

ImGearRecErrorCodes 

Not implemented

ImGearRecFillingMethod 

Not implemented

ImGearRecFilter

ImGearOCRFilter

ImGearRecFontFlags 

Not implemented

ImGearRecInvertMode 

ImGearOCRInvertMode

ImGearRecLanguage 

ImGearOCRLanguage

ImGearRecLicenseFeature 

Not implemented

ImGearRecMakeupInfo 

Not implemented

ImGearRecModule 

Not implemented

ImGearRecMrcQuality 

Not implemented

ImGearRecOrientationMode 

ImGearOCROrientationMode

ImGearRecOutputCodePageType 

Not implemented

ImGearRecOutputLevel

Not implemented

ImGearRecProcess 

Not implemented

ImGearRecRecognitionModule 

Not implemented

ImGearRecReductionMode 

ImGearOCRReductionMode

ImGearRecResEnhancementMode 

Not implemented

ImGearRecSpaceType 

Not implemented

ImGearRecTradeoff 

Not implemented

ImGearRecZoneCheckingFlags 

Not implemented

ImGearRecZoneType 

Not implemented

ImGearRecOrientationMode

ImGearOCROrientationMode

Structures

ImGearRecCodePage 

Not implemented

ImGearRecOutputFormat

Not implemented

Delegates

ImGearRecCheckWordEventHandler 

Not implemented

ImGearRecProgressEventHandler 

Not implemented

Migrating Your Code to Use the New OCR

This section provides code examples that will help you migrate your code using the old Recognition component API to the new OCR component API.

Create the Recognition Object

Previously using Recognition
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ImGearRecognition recognitionEngine = new ImGearRecognition(resourcePath);

Where resourcePath is a path to the Recognition binaries.

Currently using OCR
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ImGearOCR recognitionEngine = ImGearOCR.Create(resourcePath);

Where resourcePath is a path to the OCR binaries.

Import Raster Page to the Recognition Engine

Previously using Recognition
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ImGearRecPage recognitionPage = recognitionEngine.ImportPage((ImGearRasterPage)igPage);
Currently using OCR
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ImGearOCRPage ocrPage = recognitionEngine.ImportPage((ImGearRasterPage)igPage);

Enable Recognition Languages

Previously using Recognition
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foreach(ImGearRecLanguage lang in ImGearRecLanguage_collection)
     recognitionEngine.Recognition.LanguageEnabled[lang] = true;
Currently using OCR
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foreach(ImGearOCRLanguage lang in ImGearOCRLanguage_collection)
     recognitionEngine.Settings.LanguageEnabled[lang] = true;

Specify Zones

Previously using Recognition
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ImGearRecZone zone = new ImGearRecZone();
zone.Rect.Left = 0;
zone.Rect.Top = 0;
zone.Rect.Right = rasterPage.DIB.Width - 1;
zone.Rect.Bottom = rasterPage.DIB.Height - 1;
recognitionPage.Zones.Add(zone);
Currently using OCR
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ImGearOCRZone zone = new ImGearOCRZone();
zone.Rect.Left = 0;
zone.Rect.Top = 0;
zone.Rect.Right = rasterPage.DIB.Width - 1;
zone.Rect.Bottom = rasterPage.DIB.Height - 1;
recognitionPage.Zones.Add(zone);

Explicit Preprocessing

Previously using Recognition
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// Reduce to bitonal
recPage.Image.ReduceToBitonal(ImGearRecReductionMode.AUTO, 50, 0, ImGearRecResEnhancementMode.YES);
// Invert the image
recPage.Image.Invert();
// Despeckle
recPage.Image.Despeckle();
// Deskew and unorient
int slope;
ImGearRecOrientationMode orient;
recPage.Image.DetectSkew(out slope, out orient);
recPage.Image.Orient(orient);
recPage.Image.Deskew(slope);
Currently using OCR
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// Reduce to bitonal
ocrPage.Image.ReduceToBitonal(ImGearOCRReductionMode.AUTO, 50, 0)
// Invert the image
ocrPage.Image.Invert();
// Despeckle
ocrPage.Image.Despeckle();
// Deskew and unorient
int slope;
ImGearOCROrientationMode orient;
ocrPage.Image.DetectSkew(out slope, out orient);
ocrPage.Image.Orient(orient);
ocrPage.Image.Deskew(slope);

See ReduceToBitonal method for more information.

Implicit Preprocessing

Previously using Recognition
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rec.Preprocessing.OrientationMode = ImGearRecOrientationMode.AUTO;
rec.Preprocessing.DeskewMode = ImGearRecDeskewMode.AUTO;
rec.Preprocessing.DespeckleMode = true;
rec.Preprocessing.InversionMode = true;
recPage.Image.Preprocess();
Currently using OCR
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ocr.Preprocessing.OrientationMode = ImGearOCROrientationMode.AUTO;
ocr.Preprocessing.DeskewMode = ImGearOCRDeskewMode.AUTO;
ocr.Preprocessing.DespeckleMode = true;
ocr.Preprocessing.InversionMode = true;
ocrPage.Image.Preprocess();
Reducing to bitonal is always performed in OCR when ocrPage.Image.Preprocess(); is called.

Recognize the Page

Recognition
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recPage.Recognize();
Currently using OCR
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ocrPage.Recognize();

Get Recognition Result as an Array of Letters

Previously using Recognition
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ImGearRecLetter[] letters = recPage.GetLetters();
// ... do something with letters
Currently using OCR
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ImGearOCRLetter[] letters = ocrPage.GetLetters();
// ... do something with letters

Get Direct Text

The functionality of Direct Text output is similar to that in previous versions of ImageGear. Although ImGearRecOutputManager was removed from the product, all overrides of the WriteDirectTextOutput method may be found in the ImGearOCR object:

Currently using OCR
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void WriteDirectText(ImGearOCRPage, string);
void WriteDirectText(ImGearOCRPage[], string);
void WriteDirectText(ImGearOCRPage, Stream);
void WriteDirectText(ImGearOCRPage[], Stream);

The property ImGearRecOutputManager.DirectTextFormat has been migrated into ImGearOCRSettings. The type of this property still contains four values: SimpleText, CommaSeparatedText, FormattedText and XmlWithCoordinates. The formats of SimpleText, CommaSeparatedText and FormattedText are the same. XmlWithCoordinates was changed but contains the same information.

Get the Output as PDF Page and Save it to PDF File

Previously using Recognition
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using (ImGearPDFDocument pdfDocument = new ImGearPDFDocument())
{
    recPage.CreatePDFPage(pdfDocument, somePDFOptions);
    pdfDocument.Save(outputPDFPath, ImGearSavingFormats.PDF, 0, 0, (int)ImGearPDFPageRange.ALL_PAGES, ImGearSavingModes.OVERWRITE);
}
Currently using OCR
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using (ImGearPDFDocument pdfDocument = new ImGearPDFDocument())
{
    ocrPage.CreatePDFPage(pdfDocument, somePDFOptions);
    pdfDocument.Save(outputPDFPath, ImGearSavingFormats.PDF, 0, 0, (int)ImGearPDFPageRange.ALL_PAGES, ImGearSavingModes.OVERWRITE);
}

Exception Handling

The new OCR component implements the exception class ImGearOCRException. This class is derived from ImGearException and indicates if a failure occurred during OCR operations.

See also the information on error codes and error handling.

Currently using OCR
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try
{
    // Some OCR operation
}
catch(ImGearOCRException ex)
{
    Console.WriteLine("OCR-specific exception: " + ex.Message);
}
catch(Exception ex)
{
    Console.WriteLine("Generic exception: " + ex.Message);
}

 

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