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

Namespace: IronOcr

Assembly: IronOcr.dll

Syntax

public class IronTesseract : Object

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

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 using 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()

Read(OcrInput)

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(OcrInput Input)

Parameters

Type	Name	Description
OcrInput	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, CropRectangle)

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

Declaration

public OcrResult Read(AnyBitmap Image, CropRectangle 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.CropRectangle	ContentArea	Specifies a region within the image to extract text from as a IronSoftware.Drawing.CropRectangle 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(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, CropRectangle)

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

Declaration

public OcrResult Read(string ImagePath, CropRectangle ContentArea)

Parameters

Type	Name	Description
System.String	ImagePath	Path to an image file.
IronSoftware.Drawing.CropRectangle	ContentArea	Specifies a region within the image to extract text from as a IronSoftware.Drawing.CropRectangle 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(OcrInput, 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(OcrInput Input, int TimeoutMs = -1)

Parameters

Type	Name	Description
OcrInput	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, CropRectangle, Int32)

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

Declaration

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

Parameters

Type	Name	Description
IronSoftware.Drawing.AnyBitmap	Image	An IronSoftware.Drawing.AnyBitmap object
IronSoftware.Drawing.CropRectangle	ContentArea	Specifies a region within the image to extract text from as a IronSoftware.Drawing.CropRectangle 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, CropRectangle, Int32)

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

Declaration

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

Parameters

Type	Name	Description
System.String	ImagePath	Path to an image file.
IronSoftware.Drawing.CropRectangle	ContentArea	Specifies a region within the image to extract text from as a IronSoftware.Drawing.CropRectangle 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.

ReadPdfAndOverlayText(Byte[], String, String)

This will take a PDF document and overlay text read by tesseract on top of the pages. This will preserve bookmarks from the original document.

Declaration

public byte[] ReadPdfAndOverlayText(byte[] pdf, string password = null, string ownerPassword = null)

Parameters

Type	Name	Description
System.Byte[]	pdf	PDF to read and overlay text on as bytes.
System.String	password	Password of the input PDF if there is one.
System.String	ownerPassword	Owner password of the input PDF if there is one.

Returns

Type	Description
System.Byte[]	Returns the new PDF as a byte[]. To save in one step use ReadPdfAndOverlayText(Byte[], String, String).

See Also

ReadPdfAndOverlayText(Byte[], String, String)

ReadPdfAndOverlayText(String, String, String)

This will take a PDF document and overlay text read by tesseract on top of the pages. This will preserve bookmarks from the original document.

Declaration

public byte[] ReadPdfAndOverlayText(string pdfFilePath, string password = null, string ownerPassword = null)

Parameters

Type	Name	Description
System.String	pdfFilePath	Path to the PDF that needs selectable text overlay-ed on it.
System.String	password	Password of the input PDF if there is one.
System.String	ownerPassword	Owner password of the input PDF if there is one.

Returns

Type	Description
System.Byte[]	Returns the new PDF as a byte[]. To save in one step use ReadPdfAndOverlayText(String, String, String).

See Also

ReadPdfAndOverlayText(String, String, String)

ReadPdfAndOverlayTextSaveAs(Byte[], String, String, String)

This will take a PDF document and overlay text read by tesseract on top of the pages. This will preserve bookmarks from the original document.

Declaration

public void ReadPdfAndOverlayTextSaveAs(byte[] pdf, string pdfSavePath, string password = null, string ownerPassword = null)

Parameters

Type	Name	Description
System.Byte[]	pdf	PDF to read and overlay text on as bytes.
System.String	pdfSavePath	Path to save the new PDF.
System.String	password	Password of the input PDF if there is one.
System.String	ownerPassword	Owner password of the input PDF if there is one.

ReadPdfAndOverlayTextSaveAs(String, String, String, String)

This will take a PDF document and overlay text read by tesseract on top of the pages. This will preserve bookmarks from the original document.

Declaration

public void ReadPdfAndOverlayTextSaveAs(string pdfFilePath, string pdfSavePath, string password = null, string ownerPassword = null)

Parameters

Type	Name	Description
System.String	pdfFilePath	Path to the PDF that needs selectable text overlay-ed on it.
System.String	pdfSavePath	Path to save the new PDF.
System.String	password	Password of the input PDF if there is one.
System.String	ownerPassword	Owner password of the input PDF if there is one.

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