Migrating from the Recognition Component to the OCR Component

In This Topic

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
Import Raster Page to the Recognition Engine
Enable Recognition Languages
Specify Zones
Explicit Preprocessing
Implicit Preprocessing
Recognize the Page
Get Recognition Result as an Array of Letters
Get Direct Text
Get the Output as PDF Page and Save it to PDF File
Exception Handling

Create the Recognition Object

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

Where resourcePath is a path to the Recognition binaries.

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

Where resourcePath is a path to the OCR binaries.

Import Raster Page to the Recognition Engine

Previously using Recognition	Copy Code
ImGearRecPage recognitionPage = recognitionEngine.ImportPage((ImGearRasterPage)igPage);

Currently using OCR	Copy Code
ImGearOCRPage ocrPage = recognitionEngine.ImportPage((ImGearRasterPage)igPage);

Enable Recognition Languages

Previously using Recognition	Copy Code
foreach(ImGearRecLanguage lang in ImGearRecLanguage_collection) recognitionEngine.Recognition.LanguageEnabled[lang] = true;

Currently using OCR	Copy Code
foreach(ImGearOCRLanguage lang in ImGearOCRLanguage_collection) recognitionEngine.Settings.LanguageEnabled[lang] = true;

Specify Zones

Previously using Recognition	Copy Code
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);

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	Copy Code
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);

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	Copy Code
// 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);

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	Copy Code
// 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);

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	Copy Code
rec.Preprocessing.OrientationMode = ImGearRecOrientationMode.AUTO; rec.Preprocessing.DeskewMode = ImGearRecDeskewMode.AUTO; rec.Preprocessing.DespeckleMode = true; rec.Preprocessing.InversionMode = true; recPage.Image.Preprocess();

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	Copy Code
ocr.Preprocessing.OrientationMode = ImGearOCROrientationMode.AUTO; ocr.Preprocessing.DeskewMode = ImGearOCRDeskewMode.AUTO; ocr.Preprocessing.DespeckleMode = true; ocr.Preprocessing.InversionMode = true; ocrPage.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	Copy Code
recPage.Recognize();

Currently using OCR	Copy Code
ocrPage.Recognize();

Get Recognition Result as an Array of Letters

Previously using Recognition	Copy Code
ImGearRecLetter[] letters = recPage.GetLetters(); // ... do something with letters

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

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	Copy Code
using (ImGearPDFDocument pdfDocument = new ImGearPDFDocument()) { ocrPage.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	Copy Code
try { // Some OCR operation } catch(ImGearOCRException ex) { Console.WriteLine("OCR-specific exception: " + ex.Message); } catch(Exception ex) { Console.WriteLine("Generic exception: " + ex.Message); }

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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