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Merge pull request #1904 from syncfusion-content/997098-dev
997098-dev: Added volume 4 UG changes in PDF library.
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‎Document-Processing/PDF/PDF-Library/NET/Supported-and-Unsupported-Features.md‎

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---
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title: Supported and Unsupported Features | Syncfusion
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title: Supported and Unsupported PDF Features | Syncfusion
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description: This section explains about features available in Essential PDF and their availability in different platforms.
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platform: document-processing
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control: PDF
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documentation: UG
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---
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# Supported and Unsupported Features
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# Supported and Unsupported PDF Features
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The following table shows the various features available in the Essential<sup>&reg;</sup> PDF and their availability in different platforms.
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PDF/x1a: 2001 Compliance<br/><br/></td><td>
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Yes<br/><br/></td><td>
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Yes<br/><br/></td><td>
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No<br/><br/></td>
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<td>No<br/><br/></td>
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<td>No<br/><br/></td>
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<td>No<br/><br/></td></tr>
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Yes<br/><br/></td>
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<td>Yes<br/><br/></td>
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<td>Yes<br/><br/></td>
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<td>Yes<br/><br/></td></tr>
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<tr>
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<td>
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ZUGFeRD Invoice<br/><br/></td><td>

‎Document-Processing/PDF/PDF-Library/NET/Working-with-OCR/Features.md‎

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## Performing OCR with tesseract version 3.05
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The [TesseractVersion](https://help.syncfusion.com/cr/document-processing/Syncfusion.OCRProcessor.OCRSettings.html#Syncfusion_OCRProcessor_OCRSettings_TesseractVersion) property is used to switch the tesseract version between 3.02 and 3.05. By default, OCR works with tesseract version 3.02.
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The [TesseractVersion](https://help.syncfusion.com/cr/document-processing/Syncfusion.OCRProcessor.OCRSettings.html#Syncfusion_OCRProcessor_OCRSettings_TesseractVersion) property is used to switch the tesseract version between 3.02 and 3.05. By default, OCR works with tesseract version 5.0.
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N> The starting supported version of tesseract in ASP.NET Core is 4.0. So the lower tesseract versions 3.02 and 3.05 are not supported and we don't have the property called ``TesseractVersion`` in ASP.NET Core platform.
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## Performing OCR with Tesseract Version 4.0
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The [TesseractVersion](https://help.syncfusion.com/cr/document-processing/Syncfusion.OCRProcessor.OCRSettings.html#Syncfusion_OCRProcessor_OCRSettings_TesseractVersion) property is used to switch the tesseract version to 4.0. By default, OCR will be performed with tesseract version 3.02.
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N> In ASP.NET Core platform, the default and starting supported version of tesseract is 4.0. So we did not have the property called ``TesseractVersion`` in ASP.NET Core platform.
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The [TesseractVersion](https://help.syncfusion.com/cr/document-processing/Syncfusion.OCRProcessor.OCRSettings.html#Syncfusion_OCRProcessor_OCRSettings_TesseractVersion) property is used to switch the tesseract version to 4.0. By default, OCR will be performed with tesseract version 5.0.
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The following code sample explains the OCR processor with Tesseract version 4.0 for PDF documents.
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{% endtabs %}
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## Performing OCR with Tesseract Version 5.0
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The [TesseractVersion](https://help.syncfusion.com/cr/document-processing/Syncfusion.OCRProcessor.OCRSettings.html#Syncfusion_OCRProcessor_OCRSettings_TesseractVersion) property is used to switch the tesseract version to 5.0. By default, OCR will be performed with tesseract version 5.0.
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The following code sample explains the OCR processor with Tesseract version 5.0 for PDF documents.
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{% tabs %}
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{% highlight c# tabtitle="C# [Cross-platform]" %}
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using Syncfusion.OCRProcessor;
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using Syncfusion.Pdf.Parsing;
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//Initialize the OCR processor.
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using (OCRProcessor processor = new OCRProcessor())
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{
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//Load an existing PDF document.
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PdfLoadedDocument document = new PdfLoadedDocument("Input.pdf");
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//Set OCR language.
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processor.Settings.Language = Languages.English;
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//Set tesseract OCR Engine.
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processor.Settings.TesseractVersion = TesseractVersion.Version5_0;
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//Perform OCR with input document, tessdata (Language packs) and enabling isMemoryOptimized property.
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processor.PerformOCR(document);
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//Save the PDF document.
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document.Save("Output.pdf);
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//Close the document.
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document.Close(true);
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}
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{% endhighlight %}
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{% highlight vb.net tabtitle="VB.NET [Windows-specific]" %}
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Imports Syncfusion.OCRProcessor
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Imports Syncfusion.Pdf.Parsing
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'Initialize the OCR processor with tesseract binaries folder path.
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Using processor As OCRProcessor = New OCRProcessor("TesseractBinaries/5.0/")
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'Load an existing PDF document.
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Dim document As PdfLoadedDocument = New PdfLoadedDocument("Input.pdf")
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'Set OCR language.
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processor.Settings.Language = Languages.English
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'Set tesseract OCR Engine.
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processor.Settings.TesseractVersion = TesseractVersion.Version5_0
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'Perform OCR with input document, tessdata (Language packs) and enabling isMemoryOptimized property.
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processor.PerformOCR(document)
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'Save the PDF document.
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document.Save("Output.pdf")
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'Close the document.
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document.Close(True)
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End Using
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{% endhighlight %}
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{% endtabs %}
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## Performing OCR on image
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The below code example illustrates how to perform OCR on image file using [PerformOCR](https://help.syncfusion.com/cr/document-processing/Syncfusion.OCRProcessor.OCRProcessor.html#Syncfusion_OCRProcessor_OCRProcessor_PerformOCR_System_Drawing_Bitmap_System_String_) method in [OCRProcessor](https://help.syncfusion.com/cr/document-processing/Syncfusion.OCRProcessor.OCRProcessor.html) class.
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N> The OCR Engine Mode is supported only in the Tesseract version 4.0 and above.
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## Performing OCR with different OCR Image Enhancement Mode
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The `ImageEnhancementMode` property is used to set the OCR image enhancement modes. By default, OCR works with the `EnhanceForRecognitionOnly` image enhancement mode. Kindly refer to the following code example to perform OCR with different OCR image enhancement segmentation mode.
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The following table describes the available OCR image enhancement modes and their respective purposes.
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<table>
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<thead>
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<tr>
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<th>
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OCR Image Enhancement Mode<br/><br/></th><th>
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Description<br/><br/></th></tr>
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</thead>
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<tbody>
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<tr>
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<td>
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EnhanceForRecognitionOnly<br/><br/></td><td>
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Image is enhanced internally to improve OCR accuracy, but the original image is retained in the output.<br/><br/></td></tr>
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<tr>
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<td>
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EnhanceAndIncludeInOutput<br/><br/></td><td>
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Image is enhanced and the enhanced version is used in the output document.<br/><br/></td></tr>
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<tr>
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<td>
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None<br/><br/></td><td>
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No image enhancement is performed. The original image is used for OCR processing.<br/><br/></td></tr>
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</tbody>
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</table>
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{% tabs %}
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{% highlight c# tabtitle="C# [Cross-platform]" %}
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using Syncfusion.OCRProcessor;
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using Syncfusion.Pdf.Parsing;
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// Initialize the OCR processor
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using (OCRProcessor processor = new OCRProcessor())
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{
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// Load an existing PDF document
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PdfLoadedDocument document = new PdfLoadedDocument("Input.pdf");
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// Set the OCR language to English for text recognition.
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processor.Settings.Language = Languages.English;
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// Set the OCR image enhancement mode to improve recognition accuracy.
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processor.ImageEnhancementMode = OcrImageEnhancementMode.EnhanceForRecognitionOnly;
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// Perform OCR with input document and tessdata (Language packs)
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processor.PerformOCR(document);
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// Save the processed PDF document
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document.Save("Output.pdf");
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// Close the document
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document.Close(true);
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}
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{% endhighlight %}
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{% highlight vb.net tabtitle="VB.NET [Windows-specific]" %}
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Imports Syncfusion.OCRProcessor
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Imports Syncfusion.Pdf.Parsing
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' Initialize the OCR processor
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Using processor As New OCRProcessor()
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' Load an existing PDF document
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Dim document As New PdfLoadedDocument("Input.pdf")
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' Set the OCR language to English for text recognition
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processor.Settings.Language = Languages.English
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' Set the OCR image enhancement mode to improve recognition accuracy
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processor.ImageEnhancementMode = OcrImageEnhancementMode.EnhanceForRecognitionOnly
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' Perform OCR with input document and tessdata (Language packs)
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processor.PerformOCR(document)
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' Save the processed PDF document
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document.Save("Output.pdf")
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' Close the document
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document.Close(True)
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End Using
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{% endhighlight %}
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{% endtabs %}
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## Performing OCR with different OCR Image Enhancement options
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The `ImageEnhancementMode` property is used to set the OCR image enhancement mode. Refer to the following code example to perform OCR with different image enhancement options.
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The following table describes the available OCR image enhancement options and their respective purposes.
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<table>
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<thead>
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<tr>
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<th>
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OCR Image Enhancement options<br/><br/></th><th>
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Description<br/><br/></th></tr>
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</thead>
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<tbody>
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<tr>
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<td>
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IsGrayscaleEnabled<br/><br/></td><td>
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Simplifies image data by removing color information, making text easier to detect.<br/><br/></td></tr>
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<td>
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IsDeskewEnabled<br/><br/></td><td>
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Corrects tilted or rotated text for proper alignment.<br/><br/></td></tr>
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IsDenoiseEnabled<br/><br/></td><td>
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Removes speckles and artifacts that can interfere with character recognition.<br/><br/></td></tr>
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<tr>
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<td>
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IsConstrastEnabled<br/><br/></td><td>
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Enhances text visibility against the background.<br/><br/></td></tr>
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<td>
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IsBinarizeEnabled<br/><br/></td><td>
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Converts images to black-and-white for sharper text edges, using advanced thresholding methods.<br/><br/></td></tr>
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</tbody>
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</table>
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{% tabs %}
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{% highlight c# tabtitle="C# [Cross-platform]" %}
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using Syncfusion.OCRProcessor;
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using Syncfusion.Pdf.Parsing;
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// Initialize the OCR processor
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using (OCRProcessor processor = new OCRProcessor())
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{
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// Load an existing PDF document
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PdfLoadedDocument document = new PdfLoadedDocument("Input.pdf");
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// Set the OCR language to English for text recognition.
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processor.Settings.Language = Languages.English;
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// Set the options for image enhancement during the OCR process.
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OcrImageEnhancementOptions options = new OcrImageEnhancementOptions();
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// Enable grayscale conversion to improve OCR accuracy by reducing color noise.
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options.IsGrayscaleEnabled = true;
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// Perform OCR with input document and tessdata (Language packs)
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processor.PerformOCR(document);
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// Save the processed PDF document
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document.Save("Output.pdf");
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// Close the document
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document.Close(true);
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}
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{% endhighlight %}
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{% highlight vb.net tabtitle="VB.NET [Windows-specific]" %}
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Imports Syncfusion.OCRProcessor
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Imports Syncfusion.Pdf.Parsing
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' Initialize the OCR processor inside a Using block to ensure proper disposal.
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Using processor As New OCRProcessor()
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' Load an existing PDF document.
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Dim document As New PdfLoadedDocument("Input.pdf")
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' Set the OCR language to English for text recognition.
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processor.Settings.Language = Languages.English
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' Set the options for image enhancement during the OCR process.
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Dim options As New OcrImageEnhancementOptions()
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' Enable grayscale conversion to improve OCR accuracy by reducing color noise.
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options.IsGrayscaleEnabled = True
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' Perform OCR on the input document using tessdata (language packs).
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processor.PerformOCR(document)
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' Save the processed PDF document.
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document.Save("Output.pdf")
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' Close the document and release resources.
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document.Close(True)
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End Using
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{% endhighlight %}
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{% endtabs %}
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## White List
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The [WhiteList](https://help.syncfusion.com/cr/document-processing/Syncfusion.OCRProcessor.OCRSettings.html#Syncfusion_OCRProcessor_OCRSettings_WhiteList) property specifies a list of characters that the OCR engine is only allowed to recognize. If a character is not on the white list, it will not be included in the output OCR results. For more information, refer to the following code sample.

‎Document-Processing/PDF/PDF-Library/NET/Working-with-OCR/Working-with-OCR.md‎

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Optical character recognition (OCR) is a technology used to convert scanned paper documents in the form of PDF files or images into searchable and editable data.
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The [Syncfusion<sup>&reg;</sup> OCR processor library](https://www.syncfusion.com/document-processing/pdf-framework/net/pdf-library/ocr-process) has extended support to process OCR on scanned PDF documents and images with the help of Google’s [Tesseract](https://github.com/tesseract-ocr/tesseract) Optical Character Recognition engine.
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The [Syncfusion<sup>&reg;</sup> OCR processor library](https://www.syncfusion.com/document-processing/pdf-framework/net/pdf-library/ocr-process) has extended support to process OCR on scanned PDF documents and images with the help of Google’s [Tesseract](https://github.com/tesseract-ocr/tesseract) Optical Character Recognition engine.
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An inbuilt `image preprocessor` has been added to the OCR to prepare images for optimal recognition. This step ensures cleaner input and reduces OCR errors. The preprocessor supports the following enhancements:
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* **Convert to Grayscale** – Simplifies image data by removing color information, making text easier to detect.
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* **Deskew** – Corrects tilted or rotated text for proper alignment.
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* **Denoise** – Removes speckles and artifacts that can interfere with character recognition.
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* **Apply Contrast Adjustment** – Enhances text visibility against the background.
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* **Apply Binarize** – Converts images to black-and-white for sharper text edges, using advanced thresholding methods
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The Syncfusion<sup>&reg;</sup> OCR processor library works seamlessly in various platforms: Azure App Services, Azure Functions, AWS Textract, Docker, WinForms, WPF, Blazor, ASP.NET MVC, ASP.NET Core with Windows, MacOS and Linux.
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ASP.NET MVC4
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</td>
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<td>
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{{'[Syncfusion.Pdf.OCR.AspNet.Mvc4.nupkg](https://www.nuget.org/packages/Syncfusion.Pdf.OCR.AspNet.Mvc4)'| markdownify }}
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ASP.NET MVC5
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<li>Syncfusion.OCRProcessor.Base.dll</li>
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<li>Syncfusion.Pdf.Base.dll</li>
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<li>Syncfusion.Compression.Base.dll</li>
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<li>Syncfusion.ImagePreProcessor.Base.dll</li>
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<li>{{'[SkiaSharp](https://www.nuget.org/packages/SkiaSharp/2.88.0-preview.232)'| markdownify }} package</li>
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<li>{{'[SkiaSharp](https://www.nuget.org/packages/SkiaSharp/3.119.1)'| markdownify }} package</li>
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<li>Syncfusion.ImagePreProcessor.Portable.dll</li>
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</ul>
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</tr>
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<tr>
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<td>
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.NET 8/.NET 9
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.NET 8/.NET 9/.NET 10
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</td>
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<td>
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<ul>
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<li>Syncfusion.OCRProcessor.NET.dll</li>
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<li>{{'[SkiaSharp](https://www.nuget.org/packages/SkiaSharp/2.88.0-preview.232)'| markdownify }} package</li>
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<li>{{'[SkiaSharp](https://www.nuget.org/packages/SkiaSharp/3.119.1)'| markdownify }} package</li>
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<li>Syncfusion.ImagePreProcessor.NET.dll</li>
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‎Document-Processing/PDF/PDF-Library/NET/Working-with-PDF-Conformance.md‎

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{% highlight c# tabtitle="C# [Cross-platform]" %}
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//Creating PDF/X-conformance documents is not supported on C#.NET cross-platform environments.
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using Syncfusion.Pdf;
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using Syncfusion.Pdf.Graphics;
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//Create a new document with PDF/x standard.
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PdfDocument document = new PdfDocument(PdfConformanceLevel.Pdf_X1A2001);
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//Add a page.
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PdfPage page = document.Pages.Add();
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//Set color space.
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document.ColorSpace = PdfColorSpace.CMYK;
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//Create Pdf graphics for the page.
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PdfGraphics graphics = page.Graphics;
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//Create a solid brush.
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PdfBrush brush = new PdfSolidBrush(Color.Black);
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//Load the TrueType font from the local file.
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FileStream fontStream = new FileStream("Arial.ttf", FileMode.Open, FileAccess.Read);
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//Set the font.
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PdfFont font = new PdfTrueTypeFont(fontStream, 14);
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//Draw the text.
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graphics.DrawString("Hello world!", pdfFont, brush, new PointF(20, 20));
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//Save and close the document.
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document.Save("Output.pdf");
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document.Close(true);
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{% endhighlight %}
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