Get Started with OCR in C# and VB.NET

IronOCR is a C# software library allowing .NET platform software developers to recognize and read text from images and PDF documents. It is a pure .NET OCR library using the most advanced Tesseract engine known, anywhere.

Installation

Install with NuGet Package Manager

Install IronOcr in Visual Studio or at the command line with the NuGet Package Manager. In Visual Studio, navigate to the console with:

Tools ->
NuGet Package Manager ->
Package Manager Console

PM > Install-Package IronOcr

And check out IronOcr on NuGet for more about version updates and installation.

There are other IronOCR NuGet Packages available for different platforms:

Windows: https://www.nuget.org/packages/IronOcr
Linux: https://www.nuget.org/packages/IronOcr.Linux
MacOs: https://www.nuget.org/packages/IronOcr.MacOs
MacOs (ARM): https://www.nuget.org/packages/IronOcr.MacOs.ARM

Download the IronOCR .ZIP

You may also choose to download IronOCR via .ZIP file instead. Click to directly download the DLL. Once you have the .zip downloaded:

Instructions for .NET Framework 4.0+ Installation:

Include the IronOcr.dll in net40 folder into your project
And then add Assembly references to:
- System.Configuration
- System.Drawing
- System.Web

Instructions for .NET Standard & .NET Core 2.0+, & .NET 5

Include the IronOcr.dll in netstandard2.0 folder into your project
And then add a NuGet Package Reference to:
- System.Drawing.Common 4.7 or higher

Download the IronOCR Installer (Windows only)

Another option is to download our IronOCR installer which will install all the required resources for IronOCR to work out-of-the-box. Please keep in mind this option is only for Windows systems. To download the installer please click here. Once you have the .zip downloaded:

Instructions for .NET Framework 4.0+ Installation:

Include the IronOcr.dll in net40 folder into your project
And then add Assembly references to:
- System.Configuration
- System.Drawing
- System.Web

Instructions for .NET Standard & .NET Core 2.0+, & .NET 5

Include the IronOcr.dll in netstandard2.0 folder into your project
And then add a NuGet Package Reference to:
- System.Drawing.Common 4.7 or higher

Why Choose IronOCR?

IronOCR is an easy-to-install, complete and well-documented .NET software library.

Choose IronOCR to achieve 99.8%+ OCR accuracy without using any external web services, ongoing fees or sending confidential documents over the internet.

Why C# developers choose IronOCR over Vanilla Tesseract:

Install as a single DLL or NuGet
Includes for Tesseract 5 , 4 and 3 Engines out of the box.
Accuracy 99.8% significantly outperforms regular Tesseract.
Blazing Speed and MultiThreading
MVC, WebApp, Desktop, Console & Server Application compatible
No Exes or C++ code to work with
Full PDF OCR support
To perform OCR an almost any Image file or PDF
Full .NET Core, Standard and FrameWork support
Deploy on Windows, Mac, Linux, Azure, Docker, Lambda, AWS
Read barcodes and QR codes
Export OCR as to XHTML
Export OCR to searchable PDF documents
Multithreading support
125 international languages all managed via NuGet or OcrData files
Extract Images, Coordinates, Statistics and Fonts. Not just text.
Can be used to redistribute Tesseract OCR inside commercial & proprietary applications.

IronOCR shines when working with real world images and imperfect documents such as photographs, or scans of low resolution which may have digital noise or imperfections.

Other free OCR libraries for the .NET platform such as other .NET Tesseract APIs and web services do not perform so well on these real world use cases.

OCR with Tesseract 5 - Start Coding in C#

The code sample below shows how easy it is to read text from an image using C# or VB .NET.

OneLiner

:path=/static-assets/ocr/content-code-examples/get-started/get-started-1.cs

string Text = new IronTesseract().Read(@"img\Screenshot.png").Text;

Dim Text As String = (New IronTesseract()).Read("img\Screenshot.png").Text

VB C#

Configurable Hello World

:path=/static-assets/ocr/content-code-examples/get-started/get-started-2.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();
using (OcrInput input = new OcrInput())
{
    // Add multiple images
    input.AddImage("images/sample.jpeg");

    OcrResult result = ocr.Read(input);
    Console.WriteLine(result.Text);
}

Imports IronOcr

Private ocr As New IronTesseract()
Using input As New OcrInput()
	' Add multiple images
	input.AddImage("images/sample.jpeg")

	Dim result As OcrResult = ocr.Read(input)
	Console.WriteLine(result.Text)
End Using

VB C#

C# PDF OCR

The same approach can similarly be used to extract text from any PDF document.

:path=/static-assets/ocr/content-code-examples/get-started/get-started-3.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();
using (OcrInput input = new OcrInput())
{
    // We can also select specific PDF page numnbers to OCR
    input.AddPdf("example.pdf", "password");

    OcrResult result = ocr.Read(input);
    Console.WriteLine(result.Text);

    // 1 page for every page of the PDF
    Console.WriteLine($"{result.Pages.Count()} Pages");

}

Imports IronOcr

Private ocr As New IronTesseract()
Using input As New OcrInput()
	' We can also select specific PDF page numnbers to OCR
	input.AddPdf("example.pdf", "password")

	Dim result As OcrResult = ocr.Read(input)
	Console.WriteLine(result.Text)

	' 1 page for every page of the PDF
	Console.WriteLine($"{result.Pages.Count()} Pages")

End Using

VB C#

OCR for MultiPage TIFFs

:path=/static-assets/ocr/content-code-examples/get-started/get-started-4.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();
using (OcrInput input = new OcrInput())
{
    input.AddMultiFrameTiff("multi-frame.tiff");
    OcrResult result = ocr.Read(input);
    Console.WriteLine(result.Text);
}

Imports IronOcr

Private ocr As New IronTesseract()
Using input As New OcrInput()
	input.AddMultiFrameTiff("multi-frame.tiff")
	Dim result As OcrResult = ocr.Read(input)
	Console.WriteLine(result.Text)
End Using

VB C#

Barcodes and QR

A unique feature of IronOCR is it can read barcodes and QR codes from documents while it is scanning for text. Instances of the OcrResult.OcrBarcode Class give the developer detailed information about each scanned barcode.

:path=/static-assets/ocr/content-code-examples/get-started/get-started-5.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();
ocr.Configuration.ReadBarCodes = true;

using (OcrInput input = new OcrInput())
{
    input.AddImage("img/Barcode.png");
    OcrResult Result = ocr.Read(input);
    foreach (var Barcode in Result.Barcodes)
    {
        // type and location properties also exposed
        Console.WriteLine(Barcode.Value);
    }
}

Imports IronOcr

Private ocr As New IronTesseract()
ocr.Configuration.ReadBarCodes = True

Using input As New OcrInput()
	input.AddImage("img/Barcode.png")
	Dim Result As OcrResult = ocr.Read(input)
	For Each Barcode In Result.Barcodes
		' type and location properties also exposed
		Console.WriteLine(Barcode.Value)
	Next Barcode
End Using

VB C#

OCR on Specific Areas of Images

All of IronOCR's scanning and reading methods provide the ability specify exactly which part of a page or pages we wish to read text from. This is very useful when we are looking at standardized forms and can save an awful lot of time and improve efficiency.

To use crop regions, we will need to add a system reference to System.Drawing so that we can use the System.Drawing.Rectangle object.

:path=/static-assets/ocr/content-code-examples/get-started/get-started-6.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();
using (OcrInput input = new OcrInput())
{
    // Dimensions are in pixel
    var contentArea = new System.Drawing.Rectangle() { X = 215, Y = 1250, Height = 280, Width = 1335 };

    input.Add("document.png", contentArea);

    OcrResult result = ocr.Read(input);
    Console.WriteLine(result.Text);
}

Imports IronOcr

Private ocr As New IronTesseract()
Using input As New OcrInput()
	' Dimensions are in pixel
	Dim contentArea = New System.Drawing.Rectangle() With {
		.X = 215,
		.Y = 1250,
		.Height = 280,
		.Width = 1335
	}

	input.Add("document.png", contentArea)

	Dim result As OcrResult = ocr.Read(input)
	Console.WriteLine(result.Text)
End Using

VB C#

OCR for Low Quality Scans

The IronOCR OcrInput class can fix scans that normal Tesseract can not read.

:path=/static-assets/ocr/content-code-examples/get-started/get-started-7.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();
using (OcrInput input = new OcrInput(@"img\Potter.LowQuality.tiff"))
{
    // fixes digital noise and poor scanning
    input.DeNoise();

    // fixes rotation and perspective
    input.Deskew();

    OcrResult result = ocr.Read(input);
    Console.WriteLine(result.Text);
}

Imports IronOcr

Private ocr As New IronTesseract()
Using input As New OcrInput("img\Potter.LowQuality.tiff")
	' fixes digital noise and poor scanning
	input.DeNoise()

	' fixes rotation and perspective
	input.Deskew()

	Dim result As OcrResult = ocr.Read(input)
	Console.WriteLine(result.Text)
End Using

VB C#

Export OCR results as a Searchable PDF

:path=/static-assets/ocr/content-code-examples/get-started/get-started-8.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();
using (OcrInput input = new OcrInput())
{
    input.Title = "Quarterly Report";
    input.AddImage("image1.jpeg");
    input.AddImage("image2.png");
    input.AddImage("image3.gif");

    OcrResult result = ocr.Read(input);
    result.SaveAsSearchablePdf("searchable.pdf");
}

Imports IronOcr

Private ocr As New IronTesseract()
Using input As New OcrInput()
	input.Title = "Quarterly Report"
	input.AddImage("image1.jpeg")
	input.AddImage("image2.png")
	input.AddImage("image3.gif")

	Dim result As OcrResult = ocr.Read(input)
	result.SaveAsSearchablePdf("searchable.pdf")
End Using

VB C#

TIFF to searchable PDF Conversion

:path=/static-assets/ocr/content-code-examples/get-started/get-started-9.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();
using (OcrInput input = new OcrInput())
{
    input.AddMultiFrameTiff("example.tiff");
    ocr.Read(input).SaveAsSearchablePdf("searchable.pdf");
}

Imports IronOcr

Private ocr As New IronTesseract()
Using input As New OcrInput()
	input.AddMultiFrameTiff("example.tiff")
	ocr.Read(input).SaveAsSearchablePdf("searchable.pdf")
End Using

VB C#

Export OCR results as HTML

:path=/static-assets/ocr/content-code-examples/get-started/get-started-10.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();
using (OcrInput input = new OcrInput())
{
    input.Title = "Html Title";
    input.AddImage("image1.jpeg");

    OcrResult Result = ocr.Read(input);
    Result.SaveAsHocrFile("results.html");
}

Imports IronOcr

Private ocr As New IronTesseract()
Using input As New OcrInput()
	input.Title = "Html Title"
	input.AddImage("image1.jpeg")

	Dim Result As OcrResult = ocr.Read(input)
	Result.SaveAsHocrFile("results.html")
End Using

VB C#

OCR Image Enhancement Filters

IronOCR provides unique filters to OcrInput objects to inprove OCR performance.

Image Enhancement Code Example

:path=/static-assets/ocr/content-code-examples/get-started/get-started-11.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();
using (OcrInput input = new OcrInput(@"LowQuality.jpeg"))
{
    // fixes digital noise and poor scanning
    input.DeNoise();

    // fixes rotation and perspective
    input.Deskew();

    OcrResult result = ocr.Read(input);
    Console.WriteLine(result.Text);
}

Imports IronOcr

Private ocr As New IronTesseract()
Using input As New OcrInput("LowQuality.jpeg")
	' fixes digital noise and poor scanning
	input.DeNoise()

	' fixes rotation and perspective
	input.Deskew()

	Dim result As OcrResult = ocr.Read(input)
	Console.WriteLine(result.Text)
End Using

VB C#

List of OCR Image Filters

Input filters to enhance OCR performance which are built into IronOCR include:

OcrInput.Rotate( double degrees) - Rotates images by a number of degrees clockwise. For anti-clockwise, use negative numbers.
OcrInput.Binarize() - This image filter turns every pixel black or white with no middle ground. May Improve OCR performance cases of very low contrast of text to background.
OcrInput.ToGrayScale() - This image filter turns every pixel into a shade of grayscale. Unlikely to improve OCR accuracy but may improve speed
OcrInput.Contrast() - Increases contrast automatically. This filter often improves OCR speed and accuracy in low contrast scans.
OcrInput.DeNoise() - Removes digital noise. This filter should only be used where noise is expected.
OcrInput.Invert() - Inverts every color. E.g. White becomes black : black becomes white.
OcrInput.Dilate() - Advanced Morphology. Dilation adds pixels to the boundaries of objects in an image. Opposite of Erode
OcrInput.Erode() - Advanced Morphology. Erosion removes pixels on object boundariesOpposite of Dilate
OcrInput.Deskew() - Rotates an image so it is the right way up and orthogonal. This is very useful for OCR because Tesseract tolerance for skewed scans can be as low as 5 degrees.
OcrInput.EnhanceResolution - Enhances the resolution of low quality images. This filter is not often needed because OcrInput.MinimumDPI and OcrInput.TargetDPI will automatically catch and resolve low resolution inputs.
EnhanceResolution is a setting which will automatically detect low-resolution images (which are under 275 dpi) and automatically upscale the image and then sharpen all of the text so it can be read perfectly by an OCR library. Although this operation is in itself time-consuming, it generally reduces the overall time for an OCR operation on an image.
Language IronOCR supports 22 international language packs, and the language setting can be used to select one or more multiple languages to be applied for an OCR operation.
Strategy IronOCR supports two strategies. We may choose to either go for a fast and less accurate scan of a document, or use an advanced strategy which uses some artificial intelligence models to automatically improve the accuracy of OCR text by looking at the statistical relationship of words to one another in a sentence.
ColorSpace is a setting whereby we can choose to OCR in grayscale or color. Generally, grayscale is the best option. However, sometimes when there are texts or backgrounds of similar hue but very different color, a full-color color space will provide better results.
DetectWhiteTextOnDarkBackgrounds. Generally, all OCR libraries expect to see black text on white backgrounds. This setting allows IronOCR to automatically detect negatives, or dark pages with white text, and read them.
InputImageType. This setting allows the developer to guide the OCR library as to whether it is looking at a full document or a snippet, such as a screenshot.
RotateAndStraighten is an advanced setting which allows IronOCR the unique ability to read documents which are not only rotated, but perhaps containing perspective, such as photographs of text documents.
ReadBarcodes is a useful feature which allows IronOCR to automatically read barcodes and QR codes on pages as it also reads text, without adding a large additional time burden.
ColorDepth. This setting determines how many bits per pixel the OCR library will use to determine the depth of a color. A higher color depth may increase OCR quality, but will also increase the time required for the OCR operation to complete.

125 Language Packs

IronOCR supports 125 international languages via language packs which are distributed as DLLs, which can be downloaded from this website, or also from the NuGet Package Manager.

Languages include German, French, English, Chinese, Japanese and many more. Specialist language packs exists for passport MRZ, MICR checks, Financial Data, License plates and many more. You can also use any tesseract ".traineddata" file - including ones you create yourself.

Language Example

:path=/static-assets/ocr/content-code-examples/get-started/get-started-12.cs

using IronOcr;

// PM> Install IronOcr.Languages.Arabic
IronTesseract ocr = new IronTesseract();
ocr.Language = OcrLanguage.Arabic;

using (OcrInput input = new OcrInput())
{
    input.AddImage("img/arabic.gif");
    // Add image filters if needed
    // In this case, even thought input is very low quality
    // IronTesseract can read what conventional Tesseract cannot.
    OcrResult result = ocr.Read(input);
    // Console can't print Arabic on Windows easily.
    // Let's save to disk instead.
    result.SaveAsTextFile("arabic.txt");
}

Imports IronOcr

' PM> Install IronOcr.Languages.Arabic
Private ocr As New IronTesseract()
ocr.Language = OcrLanguage.Arabic

Using input As New OcrInput()
	input.AddImage("img/arabic.gif")
	' Add image filters if needed
	' In this case, even thought input is very low quality
	' IronTesseract can read what conventional Tesseract cannot.
	Dim result As OcrResult = ocr.Read(input)
	' Console can't print Arabic on Windows easily.
	' Let's save to disk instead.
	result.SaveAsTextFile("arabic.txt")
End Using

VB C#

Multiple Language Example

It is also possible to OCR using multiple languages at the same time. This can really help get english language metadata and urls in Unicode documents.

:path=/static-assets/ocr/content-code-examples/get-started/get-started-13.cs

using IronOcr;

// PM> Install IronOcr.Languages.ChineseSimplified
IronTesseract ocr = new IronTesseract();
ocr.Language = OcrLanguage.ChineseSimplified;

// We can add any number of languages
ocr.AddSecondaryLanguage(OcrLanguage.English);

using (OcrInput input = new OcrInput())
{
    input.Add("multi-language.pdf");
    OcrResult result = ocr.Read(input);
    result.SaveAsTextFile("results.txt");
}

Imports IronOcr

' PM> Install IronOcr.Languages.ChineseSimplified
Private ocr As New IronTesseract()
ocr.Language = OcrLanguage.ChineseSimplified

' We can add any number of languages
ocr.AddSecondaryLanguage(OcrLanguage.English)

Using input As New OcrInput()
	input.Add("multi-language.pdf")
	Dim result As OcrResult = ocr.Read(input)
	result.SaveAsTextFile("results.txt")
End Using

VB C#

Detailed OCR Results Objects

IronOCR returns an OCR result object for each OCR operation. Generally, developers only use the text property of this object to get the text scanned from the image. However, the OCR results DOM is much more advanced than this.

:path=/static-assets/ocr/content-code-examples/get-started/get-started-14.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();

// Must be set to true to read barcode
ocr.Configuration.ReadBarCodes = true;
using (OcrInput Input = new OcrInput(@"images\sample.tiff"))
{
    OcrResult result = ocr.Read(Input);
    var pages = result.Pages;
    var words = pages[0].Words;
    var barcodes = result.Barcodes;
    // Explore here to find a massive, detailed API:
    // - Pages, Blocks, Paraphaphs, Lines, Words, Chars
    // - Image Export, Fonts Coordinates, Statistical Data
}

Imports IronOcr

Private ocr As New IronTesseract()

' Must be set to true to read barcode
ocr.Configuration.ReadBarCodes = True
Using Input As New OcrInput("images\sample.tiff")
	Dim result As OcrResult = ocr.Read(Input)
	Dim pages = result.Pages
	Dim words = pages(0).Words
	Dim barcodes = result.Barcodes
	' Explore here to find a massive, detailed API:
	' - Pages, Blocks, Paraphaphs, Lines, Words, Chars
	' - Image Export, Fonts Coordinates, Statistical Data
End Using

VB C#

Performance

IronOCR works out of the box with no need to performance tune or heavily modify input images.

Speed is Blazing: IronOcr.2020 + is up to 10 times faster and makes over 250% fewer errors than previous builds.

Learn More

To learn more about OCR in C#, VB, F#, or any other .NET language, please read our community tutorials, which give real world examples of how IronOCR can be used and may show the nuances of how to get the best out of this library.

A full API reference for .NET developers is also available.

Get Started with OCR in C# and VB.NET

Installation

Install with NuGet Package Manager

Download the IronOCR .ZIP

Instructions for .NET Framework 4.0+ Installation:

Instructions for .NET Standard & .NET Core 2.0+, & .NET 5

Download the IronOCR Installer (Windows only)

Instructions for .NET Framework 4.0+ Installation:

Instructions for .NET Standard & .NET Core 2.0+, & .NET 5

Why Choose IronOCR?

Why C# developers choose IronOCR over Vanilla Tesseract:

OCR with Tesseract 5 - Start Coding in C#

OneLiner

Configurable Hello World

C# PDF OCR

OCR for MultiPage TIFFs

Barcodes and QR

OCR on Specific Areas of Images

OCR for Low Quality Scans

Export OCR results as a Searchable PDF

TIFF to searchable PDF Conversion

Export OCR results as HTML

OCR Image Enhancement Filters

Image Enhancement Code Example

List of OCR Image Filters

125 Language Packs

Language Example

Multiple Language Example

Detailed OCR Results Objects

Performance

Learn More

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