Class IronTesseract

IronTesseract is a comprehensive managed class for performing Tesseract OCR in .Net applications.

IronTesseract natively supports Tesseract 3, 4 and 5 engines, and will automatically install all required binaries and language packs (tessdata) files.

Inheritance

System.Object

IronTesseract

Implements

IronSoftware.IOcrEngine

Namespace: IronOcr

Assembly: IronOcr.dll

Syntax

public class IronTesseract : Object, IOcrEngine

Constructors

IronTesseract()

Public constructor. Creates a default instance of IronTesseract

Declaration

public IronTesseract()

IronTesseract(TesseractConfiguration)

Public constructor. Creates an instance of IronTesseract with a customized TesseractConfiguration.

This allows advanced developers to fine tune Tesseract behavior.

Declaration

public IronTesseract(TesseractConfiguration Configuration)

Parameters

Type	Name	Description
TesseractConfiguration	Configuration

Fields

Configuration

An instance of TesseractConfiguration which allows fine-grained control of the underlying Tesseract OCR Engine.

Options include: Language file detail level. Page Segmentation Mode and access to the entire API of tesseract settings variables.

Declaration

public TesseractConfiguration Configuration

Field Value

Type	Description
TesseractConfiguration

Properties

EnableTesseractConsoleMessages

Gets or sets a value indicating whether Tesseract developer messages and warnings will be sent to console output.

Declaration

public bool EnableTesseractConsoleMessages { get; set; }

Property Value

Type	Description
System.Boolean

Remarks

Setting this property to true enables console output for Tesseract messages and warnings. Conversely, setting it to false disables this output.

Language

The Natural Language of the documents Which IronTesseract will read.

Default is English. Additional languages can be installed easily using Nuget https://www.nuget.org/packages?q=IronOcr.Languages or downloaded from https://ironsoftware.com/csharp/ocr/languages/

We may use multiple languages packs simultaneously with the UseMultipleLanguages method.

We can use custom Tesseract .tessdata language packs with the UseCustomTesseractLanguageFile(String) method.

Declaration

public OcrLanguage Language { get; set; }

Property Value

Type	Description
OcrLanguage

See Also

OcrLanguage

MultiThreaded

Read multiple PDF pages and images simultaneously on different threads

Declaration

public bool MultiThreaded { get; set; }

Property Value

Type	Description
System.Boolean

Methods

AddSecondaryLanguage(OcrLanguage)

IronTesseract will use multiple tesseract language files simultaneously. MultilingualOCR

Any number of secondary languages may be added. Speed and performance may be affected.

Declaration

public void AddSecondaryLanguage(OcrLanguage SecondaryLanguage)

Parameters

Type	Name	Description
OcrLanguage	SecondaryLanguage	An additional OcrLanguage

AddSecondaryLanguage(String)

IronTesseract will use multiple tesseract language files simultaneously. MultilingualOCR uses a custom .traineddata tesseract 3,4 or 5 language file.

Any number of secondary languages may be added. Speed and performance may be affected.

Declaration

public void AddSecondaryLanguage(string CustomLanguagePath)

Parameters

Type	Name	Description
System.String	CustomLanguagePath	File path to a .traineddata tesseract language pack.

ClearSecondaryLanguages()

Removes all languages add by AddSecondaryLanguage(OcrLanguage) or AddSecondaryLanguage(String)

Declaration

public void ClearSecondaryLanguages()

ConvertToSearchablePdf(Byte[], String)

Perform OCR on images within the PDF, overlay the text onto the original PDF, and return a byte array of the new PDF

Declaration

public byte[] ConvertToSearchablePdf(byte[] PdfData, string Password = null)

Parameters

Type	Name	Description
System.Byte[]	PdfData	PDF file data
System.String	Password	PDF password

Returns

Type	Description
System.Byte[]	Byte array of the generated Searchable PDF

Remarks

Useful for generating a searchable PDF which retains bookmarks, annotations, etc.

ConvertToSearchablePdf(Byte[], String, String)

Perform OCR on images within the PDF, overlay the text onto the original PDF, and save the new PDF to file

Declaration

public void ConvertToSearchablePdf(byte[] PdfData, string SavePath, string Password = null)

Parameters

Type	Name	Description
System.Byte[]	PdfData	PDF file data
System.String	SavePath	Save path of the searchable PDF
System.String	Password	PDF password

Remarks

Useful for generating a searchable PDF which retains bookmarks, annotations, etc.

ConvertToSearchablePdf(String, String)

Perform OCR on images within the PDF, overlay the text onto the original PDF, and return a byte array of the new PDF

Declaration

public byte[] ConvertToSearchablePdf(string PdfPath, string Password = null)

Parameters

Type	Name	Description
System.String	PdfPath	PDF file path
System.String	Password	PDF password

Returns

Type	Description
System.Byte[]

Remarks

Useful for generating a searchable PDF which retains bookmarks, annotations, etc.

ConvertToSearchablePdf(String, String, String)

Perform OCR on images within the PDF, overlay the text onto the original PDF, and save the new PDF to file

Declaration

public void ConvertToSearchablePdf(string PdfPath, string SavePath, string Password = null)

Parameters

Type	Name	Description
System.String	PdfPath	PDF file path
System.String	SavePath	Save path of the searchable PDF
System.String	Password	PDF password

Remarks

Useful for generating a searchable PDF which retains bookmarks, annotations, etc.

Read(OcrInputBase)

Reads text from an OcrInput object and returns an OcrResult object.

OcrInput is the preferred input type because it allows for OCR of multi-paged documents, and allows images to be enhanced before OCR to obtain faster, more accurate results.

There are also other overloads of this method that allow for Images and PDFs to be read directly as File paths and Bitmaps.

Declaration

public OcrResult Read(OcrInputBase Input)

Parameters

Type	Name	Description
OcrInputBase	Input	An OcrInput document which can contain one or more images and PDFs

Returns

Type	Description
OcrResult	A OcrResult object containing text, and detailed, structured information about the extracted text content.

Read(AnyBitmap)

Reads text from a IronSoftware.Drawing.AnyBitmap Image file and returns an OcrResult object.

Declaration

public OcrResult Read(AnyBitmap Image)

Parameters

Type	Name	Description
IronSoftware.Drawing.AnyBitmap	Image	An IronSoftware.Drawing.AnyBitmap, SixLabor.ImageSharp.Image, SkiaSharp.SKBitmap, SkiaSharp.SKImage, Microsoft.Maui.Graphics.Platform.PlatformImage, System.Drawing.Bitmap, or System.Drawing.Image

Returns

Type	Description
OcrResult	A OcrResult object containing text, and detailed, structured information about the extracted text content.

Read(AnyBitmap, Rectangle)

Reads text from a region of a IronSoftware.Drawing.AnyBitmap Image file and returns an OcrResult object.

Declaration

public OcrResult Read(AnyBitmap Image, Rectangle ContentArea)

Parameters

Type	Name	Description
IronSoftware.Drawing.AnyBitmap	Image	An IronSoftware.Drawing.AnyBitmap, SixLabor.ImageSharp.Image, SkiaSharp.SKBitmap, SkiaSharp.SKImage, Microsoft.Maui.Graphics.Platform.PlatformImage, System.Drawing.Bitmap, or System.Drawing.Image
IronSoftware.Drawing.Rectangle	ContentArea	Specifies a region within the image to extract text from as a IronSoftware.Drawing.Rectangle with X, Y Width and Height in pixels. Setting a ContentArea can improve OCR speed.

Returns

Type	Description
OcrResult	A OcrResult object containing text, and detailed, structured information about the extracted text content.

Read(IPdfDocumentId)

Read the existing Pdf document and return OCR results

Declaration

public IOcrResult Read(IPdfDocumentId Document)

Parameters

Type	Name	Description
IronSoftware.IPdfDocumentId	Document	Pdf document to read

Returns

Type	Description
IronSoftware.IOcrResult	OCR results

Read(IPdfDocumentId, PdfContents)

Read the existing Pdf document and return OCR results

Declaration

public IOcrResult Read(IPdfDocumentId Document, PdfContents Contents)

Parameters

Type	Name	Description
IronSoftware.IPdfDocumentId	Document	Pdf document to read
PdfContents	Contents	Contents to OCR

Returns

Type	Description
IronSoftware.IOcrResult	OCR results

Read(String)

Reads text from an Image file and returns an OcrResult object.

Declaration

public OcrResult Read(string ImagePath)

Parameters

Type	Name	Description
System.String	ImagePath	Path to an image file.

Returns

Type	Description
OcrResult	A OcrResult object containing text, and detailed, structured information about the extracted text content.

Read(String, Rectangle)

Reads text from a region of an Image file and returns an OcrResult object.

Declaration

public OcrResult Read(string ImagePath, Rectangle ContentArea)

Parameters

Type	Name	Description
System.String	ImagePath	Path to an image file.
IronSoftware.Drawing.Rectangle	ContentArea	Specifies a region within the image to extract text from as a IronSoftware.Drawing.Rectangle with X, Y Width and Height in pixels. Setting a ContentArea can improve OCR speed.

Returns

Type	Description
OcrResult	A OcrResult object containing text, and detailed, structured information about the extracted text content.

ReadAsync(OcrInputBase, Int32)

Reads text from an OcrInput object and returns an OcrResult object.

OcrInput is the preferred input type because it allows for OCR of multi-paged documents, and allows images to be enhanced before OCR to obtain faster, more accurate results.

There are also other overloads of this method that allow for Images and PDFs to be read directly as File paths and Bitmaps.

Declaration

public OcrReadTask ReadAsync(OcrInputBase Input, int TimeoutMs = -1)

Parameters

Type	Name	Description
OcrInputBase	Input	An OcrInput document which can contain one or more images and PDFs
System.Int32	TimeoutMs	Optional timeout in milliseconds, after which the Ocr read will be cancelled. Not supported in .NET 4.0

Returns

Type	Description
OcrReadTask	A task that represents the asynchronous read operation. The value of the System.Threading.Tasks.Task`1.Result property contains an OcrResult object containing text, and detailed, structured information about the extracted text content.

ReadAsync(AnyBitmap, Rectangle, Int32)

Reads text from an IronSoftware.Drawing.AnyBitmap object and returns an OcrResult object.

Declaration

public Task<OcrResult> ReadAsync(AnyBitmap Image, Rectangle ContentArea = null, int TimeoutMs = -1)

Parameters

Type	Name	Description
IronSoftware.Drawing.AnyBitmap	Image	An IronSoftware.Drawing.AnyBitmap object
IronSoftware.Drawing.Rectangle	ContentArea	Specifies a region within the image to extract text from as a IronSoftware.Drawing.Rectangle with X, Y Width and Height in pixels. Setting a ContentArea can improve OCR speed.
System.Int32	TimeoutMs	Optional timeout in milliseconds, after which the Ocr read will be cancelled. Not supported in .NET 4.0

Returns

Type	Description
System.Threading.Tasks.Task<OcrResult>	A task that represents the asynchronous read operation. The value of the System.Threading.Tasks.Task`1.Result property contains an OcrResult object containing text, and detailed, structured information about the extracted text content.

ReadAsync(String, Rectangle, Int32)

Reads text from an Image file and returns an OcrResult object.

Declaration

public OcrReadTask ReadAsync(string ImagePath, Rectangle ContentArea = null, int TimeoutMs = -1)

Parameters

Type	Name	Description
System.String	ImagePath	Path to an image file.
IronSoftware.Drawing.Rectangle	ContentArea	Specifies a region within the image to extract text from as a IronSoftware.Drawing.Rectangle with X, Y Width and Height in pixels. Setting a ContentArea can improve OCR speed.
System.Int32	TimeoutMs	Optional timeout in milliseconds, after which the Ocr read will be cancelled. Not supported in .NET 4.0

Returns

Type	Description
OcrReadTask	A task that represents the asynchronous read operation. The value of the System.Threading.Tasks.Task`1.Result property contains an OcrResult object containing text, and detailed, structured information about the extracted text content.

ReadImagesFromPdf(Byte[], String, IEnumerable<Int32>)

Extract all images from a PDF, perform OCR on the images, and return the results

Declaration

public OcrResult ReadImagesFromPdf(byte[] PdfData, string Password = null, IEnumerable<int> PageIndices = null)

Parameters

Type	Name	Description
System.Byte[]	PdfData	PDF file data
System.String	Password	PDF password
System.Collections.Generic.IEnumerable<System.Int32>	PageIndices	Pages to extract images from

Returns

Type	Description
OcrResult	OCR results

Remarks

Useful for generating a searchable PDF which retains bookmarks, annotations, etc.

ReadImagesFromPdf(String, String, IEnumerable<Int32>)

Extract all images from a PDF, perform OCR on the images, and return the results

Declaration

public OcrResult ReadImagesFromPdf(string PdfPath, string Password = null, IEnumerable<int> PageIndices = null)

Parameters

Type	Name	Description
System.String	PdfPath	PDF file path
System.String	Password	PDF password
System.Collections.Generic.IEnumerable<System.Int32>	PageIndices	Pages to extract images from

Returns

Type	Description
OcrResult	OCR results

Remarks

Useful for generating a searchable PDF which retains bookmarks, annotations, etc.

UseCustomTesseractLanguageFile(String)

IronTesseract will use a tesseract .traineddata language file as its only OCR language.

https://github.com/tesseract-ocr/tessdata

Declaration

public void UseCustomTesseractLanguageFile(string TrainedDataPath)

Parameters

Type	Name	Description
System.String	TrainedDataPath	File path to a .traineddata file. These can be downloaded from https://github.com/tesseract-ocr/tessdata or generated using Tesseract command line.

Events

OcrProgress

An Event which can be used to track OCR progress and inform users of OCR performance and progress.

Progress is reported via the OcrProgressEventsArgs class

Declaration

public event EventHandler<OcrProgressEventsArgs> OcrProgress

Event Type

Type	Description
System.EventHandler<OcrProgressEventsArgs>

Examples

myIronTesseract.OcrProgress += (object o, IronOcr.Events.OcrProgressEventsArgs e) =>
                   {
                      Console.WriteLine(e.ProgressPercent + "%   " + e.Duration.TotalSeconds+"s"  );
                   }

See Also

OcrProgressEventsArgs

Implements

IronSoftware.IOcrEngine