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C# OCR Image to Text Tutorial: Convert Images to Text Without Tesseract

Jacob Mellor, Chief Technology Officer @ Team Iron
ByJacob Mellor
Updated  

Looking to convert images to text in C# without the hassle of complex Tesseract configurations? This comprehensive IronOCR C# tutorial shows you how to implement powerful optical character recognition in your .NET applications with just a few lines of code.

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How to Convert Images to Text in C# Using IronOCR

  1. Download IronOCR - the C# OCR library for image to text conversion
  2. Use IronTesseract class to read text from images instantly
  3. Apply image filters to enhance OCR accuracy on low-quality scans
  4. Process multiple languages with downloadable language packs
  5. Export results as searchable PDFs or extract text strings

How Do I Read Text from Images in .NET Applications?

To achieve C# OCR image to text functionality in your .NET applications, you'll need a reliable OCR library. IronOCR provides a managed solution using the IronOcr.IronTesseract class that maximizes both accuracy and speed without requiring external dependencies.

First, install IronOCR into your Visual Studio project. You can download the IronOCR DLL directly or use NuGet Package Manager.

Install-Package IronOcr

Why Choose IronOCR for C# OCR Without Tesseract?

When you need to convert images to text in C#, IronOCR offers significant advantages over traditional Tesseract implementations:

  • Works immediately in pure .NET environments
  • No Tesseract installation or configuration required
  • Runs the latest engines: Tesseract 5 (plus Tesseract 4 & 3)
  • Compatible with .NET Framework 4.5+, .NET Standard 2+, and .NET Core 2, 3, 5, 6, 7, 8, 9, and 10
  • Improves accuracy and speed compared to vanilla Tesseract
  • Supports Xamarin, Mono, Azure, and Docker deployments
  • Manages complex Tesseract dictionaries through NuGet packages
  • Handles PDFs, MultiFrame TIFFs, and all major image formats automatically
  • Corrects low-quality and skewed scans for optimal results

Start using IronOCR in your project today with a free trial.

First Step:
green arrow pointer

How to Use IronOCR C# Tutorial for Basic OCR?

This Iron Tesseract C# example demonstrates the simplest way to read text from image using IronOCR. The IronOcr.IronTesseract class extracts text and returns it as a string.

// Basic C# OCR image to text conversion using IronOCR
// This example shows how to extract text from images without complex setup

using IronOcr;
using System;

try
{
    // Initialize IronTesseract for OCR operations
    var ocrEngine = new IronTesseract();

    // Path to your image file - supports PNG, JPG, TIFF, BMP, and more
    var imagePath = @"img\Screenshot.png";

    // Create input and perform OCR to convert image to text
    using (var input = new OcrInput(imagePath))
    {
        // Read text from image and get results
        OcrResult result = ocrEngine.Read(input);

        // Display extracted text
        Console.WriteLine(result.Text);
    }
}
catch (OcrException ex)
{
    // Handle OCR-specific errors
    Console.WriteLine($"OCR Error: {ex.Message}");
}
catch (Exception ex)
{
    // Handle general errors
    Console.WriteLine($"Error: {ex.Message}");
}
// Basic C# OCR image to text conversion using IronOCR
// This example shows how to extract text from images without complex setup

using IronOcr;
using System;

try
{
    // Initialize IronTesseract for OCR operations
    var ocrEngine = new IronTesseract();

    // Path to your image file - supports PNG, JPG, TIFF, BMP, and more
    var imagePath = @"img\Screenshot.png";

    // Create input and perform OCR to convert image to text
    using (var input = new OcrInput(imagePath))
    {
        // Read text from image and get results
        OcrResult result = ocrEngine.Read(input);

        // Display extracted text
        Console.WriteLine(result.Text);
    }
}
catch (OcrException ex)
{
    // Handle OCR-specific errors
    Console.WriteLine($"OCR Error: {ex.Message}");
}
catch (Exception ex)
{
    // Handle general errors
    Console.WriteLine($"Error: {ex.Message}");
}
' Basic C# OCR image to text conversion using IronOCR

' This example shows how to extract text from images without complex setup



Imports IronOcr

Imports System



Try

	' Initialize IronTesseract for OCR operations

	Dim ocrEngine = New IronTesseract()



	' Path to your image file - supports PNG, JPG, TIFF, BMP, and more

	Dim imagePath = "img\Screenshot.png"



	' Create input and perform OCR to convert image to text

	Using input = New OcrInput(imagePath)

		' Read text from image and get results

		Dim result As OcrResult = ocrEngine.Read(input)



		' Display extracted text

		Console.WriteLine(result.Text)

	End Using

Catch ex As OcrException

	' Handle OCR-specific errors

	Console.WriteLine($"OCR Error: {ex.Message}")

Catch ex As Exception

	' Handle general errors

	Console.WriteLine($"Error: {ex.Message}")

End Try
$vbLabelText   $csharpLabel

This code achieves 100% accuracy on clear images, extracting text exactly as it appears:

IronOCR Simple Example

In this simple example we test the accuracy of our C# OCR library to read text from a PNG Image. This is a very basic test, but things will get more complicated as the tutorial continues.

The quick brown fox jumps over the lazy dog

The IronTesseract class handles complex OCR operations internally. It automatically scans for alignment, optimizes resolution, and uses AI to read text from image using IronOCR with human-level accuracy.

Despite the sophisticated processing happening behind the scenes - including image analysis, engine optimization, and intelligent text recognition - the OCR process matches human reading speed while maintaining exceptional accuracy levels.

IronOCR Simple Example showing C# OCR image to text conversion with 100% accuracy Screenshot demonstrating IronOCR's ability to extract text from a PNG image with perfect accuracy

How to Implement Advanced C# OCR Without Tesseract Configuration?

For production applications requiring optimal performance when you convert images to text in C#, use the OcrInput and IronTesseract classes together. This approach provides fine-grained control over the OCR process.

OcrInput Class Features

  • Processes multiple image formats: JPEG, TIFF, GIF, BMP, PNG
  • Imports complete PDFs or specific pages
  • Enhances contrast, resolution, and image quality automatically
  • Corrects rotation, scan noise, skew, and negative images

IronTesseract Class Features

  • Access to 125+ prepackaged languages
  • Tesseract 5, 4, and 3 engines included
  • Document type specification (screenshot, snippet, or full document)
  • Integrated barcode reading capabilities
  • Multiple output formats: Searchable PDFs, HOCR HTML, DOM objects, and strings

How to Get Started with OcrInput and IronTesseract?

Here's a recommended configuration for this IronOCR C# tutorial that works well with most document types:

using IronOcr;

// Initialize IronTesseract for advanced OCR operations
IronTesseract ocr = new IronTesseract();

// Create input container for processing multiple images
using (OcrInput input = new OcrInput())
{
    // Process specific pages from multi-page TIFF files
    int[] pageIndices = new int[] { 1, 2 };

    // Load TIFF frames - perfect for scanned documents
    input.LoadImageFrames(@"img\Potter.tiff", pageIndices);

    // Execute OCR to read text from image using IronOCR
    OcrResult result = ocr.Read(input);

    // Output the extracted text
    Console.WriteLine(result.Text);
}
using IronOcr;

// Initialize IronTesseract for advanced OCR operations
IronTesseract ocr = new IronTesseract();

// Create input container for processing multiple images
using (OcrInput input = new OcrInput())
{
    // Process specific pages from multi-page TIFF files
    int[] pageIndices = new int[] { 1, 2 };

    // Load TIFF frames - perfect for scanned documents
    input.LoadImageFrames(@"img\Potter.tiff", pageIndices);

    // Execute OCR to read text from image using IronOCR
    OcrResult result = ocr.Read(input);

    // Output the extracted text
    Console.WriteLine(result.Text);
}
Imports IronOcr



' Initialize IronTesseract for advanced OCR operations

Private ocr As New IronTesseract()



' Create input container for processing multiple images

Using input As New OcrInput()

	' Process specific pages from multi-page TIFF files

	Dim pageIndices() As Integer = { 1, 2 }



	' Load TIFF frames - perfect for scanned documents

	input.LoadImageFrames("img\Potter.tiff", pageIndices)



	' Execute OCR to read text from image using IronOCR

	Dim result As OcrResult = ocr.Read(input)



	' Output the extracted text

	Console.WriteLine(result.Text)

End Using
$vbLabelText   $csharpLabel

This configuration consistently achieves near-perfect accuracy on medium-quality scans. The LoadImageFrames method efficiently handles multi-page documents, making it ideal for batch processing scenarios.


Multi-page TIFF document showing Harry Potter text ready for C# OCR processing

Sample TIFF document demonstrating IronOCR's multi-page text extraction capabilities

The ability to read text from images and barcodes in scanned documents like TIFFs showcases how IronOCR simplifies complex OCR tasks. The library excels with real-world documents, seamlessly handling multi-page TIFFs and PDF text extraction.

How Does IronOCR Handle Low-Quality Scans?


Low-quality scan with digital noise demonstrating IronOCR's image enhancement capabilities

Low-resolution document with noise that IronOCR can process accurately using image filters

When working with imperfect scans containing distortion and digital noise, IronOCR outperforms other C# OCR libraries. It's specifically designed for real-world scenarios rather than pristine test images.

// Advanced Iron Tesseract C# example for low-quality images
using IronOcr;
using System;

var ocr = new IronTesseract();

try
{
    using (var input = new OcrInput())
    {
        // Load specific pages from poor-quality TIFF
        var pageIndices = new int[] { 0, 1 };
        input.LoadImageFrames(@"img\Potter.LowQuality.tiff", pageIndices);

        // Apply deskew filter to correct rotation and perspective
        input.Deskew(); // Critical for improving accuracy on skewed scans

        // Perform OCR with enhanced preprocessing
        OcrResult result = ocr.Read(input);

        // Display results
        Console.WriteLine("Recognized Text:");
        Console.WriteLine(result.Text);
    }
}
catch (Exception ex)
{
    Console.WriteLine($"Error during OCR: {ex.Message}");
}
// Advanced Iron Tesseract C# example for low-quality images
using IronOcr;
using System;

var ocr = new IronTesseract();

try
{
    using (var input = new OcrInput())
    {
        // Load specific pages from poor-quality TIFF
        var pageIndices = new int[] { 0, 1 };
        input.LoadImageFrames(@"img\Potter.LowQuality.tiff", pageIndices);

        // Apply deskew filter to correct rotation and perspective
        input.Deskew(); // Critical for improving accuracy on skewed scans

        // Perform OCR with enhanced preprocessing
        OcrResult result = ocr.Read(input);

        // Display results
        Console.WriteLine("Recognized Text:");
        Console.WriteLine(result.Text);
    }
}
catch (Exception ex)
{
    Console.WriteLine($"Error during OCR: {ex.Message}");
}
' Advanced Iron Tesseract C# example for low-quality images

Imports IronOcr

Imports System



Private ocr = New IronTesseract()



Try

	Using input = New OcrInput()

		' Load specific pages from poor-quality TIFF

		Dim pageIndices = New Integer() { 0, 1 }

		input.LoadImageFrames("img\Potter.LowQuality.tiff", pageIndices)



		' Apply deskew filter to correct rotation and perspective

		input.Deskew() ' Critical for improving accuracy on skewed scans



		' Perform OCR with enhanced preprocessing

		Dim result As OcrResult = ocr.Read(input)



		' Display results

		Console.WriteLine("Recognized Text:")

		Console.WriteLine(result.Text)

	End Using

Catch ex As Exception

	Console.WriteLine($"Error during OCR: {ex.Message}")

End Try
$vbLabelText   $csharpLabel

Using Input.Deskew(), accuracy improves to 99.8% on low-quality scans, nearly matching high-quality results. This demonstrates why IronOCR is the preferred choice for C# OCR without Tesseract complications.

Image filters may slightly increase processing time but significantly reduce overall OCR duration. Finding the right balance depends on your document quality.

For most scenarios, Input.Deskew() and Input.DeNoise() provide reliable improvements to OCR performance. Learn more about image preprocessing techniques.

How to Optimize OCR Performance and Speed?

The most significant factor affecting OCR speed when you convert images to text in C# is input quality. Higher DPI (~200 dpi) with minimal noise produces the fastest and most accurate results.

While IronOCR excels at correcting imperfect documents, this enhancement requires additional processing time.

Choose image formats with minimal compression artifacts. TIFF and PNG typically yield faster results than JPEG due to lower digital noise.

Which Image Filters Improve OCR Speed?

The following filters can dramatically enhance performance in your C# OCR image to text workflow:

  • OcrInput.Rotate(double degrees): Rotates images clockwise (negative for counterclockwise)
  • OcrInput.Binarize(): Converts to black/white, improving performance in low-contrast scenarios
  • OcrInput.ToGrayScale(): Converts to grayscale for potential speed improvements
  • OcrInput.Contrast(): Auto-adjusts contrast for better accuracy
  • OcrInput.DeNoise(): Removes digital artifacts when noise is expected
  • OcrInput.Invert(): Inverts colors for white-on-black text
  • OcrInput.Dilate(): Expands text boundaries
  • OcrInput.Erode(): Reduces text boundaries
  • OcrInput.Deskew(): Corrects alignment - essential for skewed documents
  • OcrInput.DeepCleanBackgroundNoise(): Aggressive noise removal
  • OcrInput.EnhanceResolution: Improves low-resolution image quality

How to Configure IronOCR for Maximum Speed?

Use these settings to optimize speed when processing high-quality scans:

using IronOcr;

// Configure for speed - ideal for clean documents
IronTesseract ocr = new IronTesseract();

// Exclude problematic characters to speed up recognition
ocr.Configuration.BlackListCharacters = "~`$#^*_{[]}
\\";

// Use automatic page segmentation
ocr.Configuration.PageSegmentationMode = TesseractPageSegmentationMode.Auto;

// Select fast English language pack
ocr.Language = OcrLanguage.EnglishFast;

using (OcrInput input = new OcrInput())
{
    // Load specific pages from document
    int[] pageIndices = new int[] { 1, 2 };
    input.LoadImageFrames(@"img\Potter.tiff", pageIndices);

    // Read with optimized settings
    OcrResult result = ocr.Read(input);
    Console.WriteLine(result.Text);
}
using IronOcr;

// Configure for speed - ideal for clean documents
IronTesseract ocr = new IronTesseract();

// Exclude problematic characters to speed up recognition
ocr.Configuration.BlackListCharacters = "~`$#^*_{[]}
\\";

// Use automatic page segmentation
ocr.Configuration.PageSegmentationMode = TesseractPageSegmentationMode.Auto;

// Select fast English language pack
ocr.Language = OcrLanguage.EnglishFast;

using (OcrInput input = new OcrInput())
{
    // Load specific pages from document
    int[] pageIndices = new int[] { 1, 2 };
    input.LoadImageFrames(@"img\Potter.tiff", pageIndices);

    // Read with optimized settings
    OcrResult result = ocr.Read(input);
    Console.WriteLine(result.Text);
}
Imports IronOcr



' Configure for speed - ideal for clean documents

Private ocr As New IronTesseract()



' Exclude problematic characters to speed up recognition

ocr.Configuration.BlackListCharacters = "~`$#^*_{[]}
\"



' Use automatic page segmentation

ocr.Configuration.PageSegmentationMode = TesseractPageSegmentationMode.Auto



' Select fast English language pack

ocr.Language = OcrLanguage.EnglishFast



Using input As New OcrInput()

	' Load specific pages from document

	Dim pageIndices() As Integer = { 1, 2 }

	input.LoadImageFrames("img\Potter.tiff", pageIndices)



	' Read with optimized settings

	Dim result As OcrResult = ocr.Read(input)

	Console.WriteLine(result.Text)

End Using
$vbLabelText   $csharpLabel

This optimized setup maintains 99.8% accuracy while achieving a 35% speed improvement compared to default settings.

How to Read Specific Areas of Images Using C# OCR?

The Iron Tesseract C# example below shows how to target specific regions using System.Drawing.Rectangle. This technique is invaluable for processing standardized forms where text appears in predictable locations.

Can IronOCR Process Cropped Regions for Faster Results?

Using pixel-based coordinates, you can limit OCR to specific areas, dramatically improving speed and preventing unwanted text extraction:

using IronOcr;
using IronSoftware.Drawing;

// Initialize OCR engine for targeted region processing
var ocr = new IronTesseract();

using (var input = new OcrInput())
{
    // Define exact region for OCR - coordinates in pixels
    var contentArea = new System.Drawing.Rectangle(
        x: 215, 
        y: 1250, 
        width: 1335, 
        height: 280
    );

    // Load image with specific area - perfect for forms and invoices
    input.AddImage("img/ComSci.png", contentArea);

    // Process only the defined region
    OcrResult result = ocr.Read(input);
    Console.WriteLine(result.Text);
}
using IronOcr;
using IronSoftware.Drawing;

// Initialize OCR engine for targeted region processing
var ocr = new IronTesseract();

using (var input = new OcrInput())
{
    // Define exact region for OCR - coordinates in pixels
    var contentArea = new System.Drawing.Rectangle(
        x: 215, 
        y: 1250, 
        width: 1335, 
        height: 280
    );

    // Load image with specific area - perfect for forms and invoices
    input.AddImage("img/ComSci.png", contentArea);

    // Process only the defined region
    OcrResult result = ocr.Read(input);
    Console.WriteLine(result.Text);
}
Imports IronOcr

Imports IronSoftware.Drawing



' Initialize OCR engine for targeted region processing

Private ocr = New IronTesseract()



Using input = New OcrInput()

	' Define exact region for OCR - coordinates in pixels

	Dim contentArea = New System.Drawing.Rectangle(x:= 215, y:= 1250, width:= 1335, height:= 280)



	' Load image with specific area - perfect for forms and invoices

	input.AddImage("img/ComSci.png", contentArea)



	' Process only the defined region

	Dim result As OcrResult = ocr.Read(input)

	Console.WriteLine(result.Text)

End Using
$vbLabelText   $csharpLabel

This targeted approach provides a 41% speed improvement while extracting only relevant text. It's ideal for structured documents like invoices, checks, and forms. The same cropping technique works seamlessly with PDF OCR operations.

Computer Science document showing targeted OCR region extraction in C# Document demonstrating precise region-based text extraction using IronOCR's rectangle selection

How Many Languages Does IronOCR Support?

IronOCR provides 125 international languages through convenient language packs. Download them as DLLs from our website or via NuGet Package Manager.

Install language packs through the NuGet interface (search "IronOcr.Languages") or visit the complete language pack listing.

Supported languages include Arabic, Chinese (Simplified/Traditional), Japanese, Korean, Hindi, Russian, German, French, Spanish, and 115+ others, each optimized for accurate text recognition.

How to Implement OCR in Multiple Languages?

This IronOCR C# tutorial example demonstrates Arabic text recognition:

Install-Package IronOcr.Languages.Arabic
Arabic text being processed by IronOCR demonstrating multi-language OCR support

IronOCR accurately extracting Arabic text from a GIF image

// Install-Package IronOcr.Languages.Arabic
using IronOcr;

// Configure for Arabic language OCR
var ocr = new IronTesseract();
ocr.Language = OcrLanguage.Arabic;

using (var input = new OcrInput())
{
    // Load Arabic text image
    input.AddImage("img/arabic.gif");

    // IronOCR handles low-quality Arabic text that standard Tesseract cannot
    var result = ocr.Read(input);

    // Save to file (console may not display Arabic correctly)
    result.SaveAsTextFile("arabic.txt");
}
// Install-Package IronOcr.Languages.Arabic
using IronOcr;

// Configure for Arabic language OCR
var ocr = new IronTesseract();
ocr.Language = OcrLanguage.Arabic;

using (var input = new OcrInput())
{
    // Load Arabic text image
    input.AddImage("img/arabic.gif");

    // IronOCR handles low-quality Arabic text that standard Tesseract cannot
    var result = ocr.Read(input);

    // Save to file (console may not display Arabic correctly)
    result.SaveAsTextFile("arabic.txt");
}
' Install-Package IronOcr.Languages.Arabic

Imports IronOcr



' Configure for Arabic language OCR

Private ocr = New IronTesseract()

ocr.Language = OcrLanguage.Arabic



Using input = New OcrInput()

	' Load Arabic text image

	input.AddImage("img/arabic.gif")



	' IronOCR handles low-quality Arabic text that standard Tesseract cannot

	Dim result = ocr.Read(input)



	' Save to file (console may not display Arabic correctly)

	result.SaveAsTextFile("arabic.txt")

End Using
$vbLabelText   $csharpLabel

Can IronOCR Handle Documents with Multiple Languages?

When documents contain mixed languages, configure IronOCR for multi-language support:

Install-Package IronOcr.Languages.ChineseSimplified
// Multi-language OCR configuration
using IronOcr;

var ocr = new IronTesseract();

// Set primary language
ocr.Language = OcrLanguage.ChineseSimplified;

// Add secondary languages as needed
ocr.AddSecondaryLanguage(OcrLanguage.English);

// Custom .traineddata files can be added for specialized recognition
// ocr.AddSecondaryLanguage("path/to/custom.traineddata");

using (var input = new OcrInput())
{
    // Process multi-language document
    input.AddImage("img/MultiLanguage.jpeg");

    var result = ocr.Read(input);
    result.SaveAsTextFile("MultiLanguage.txt");
}
// Multi-language OCR configuration
using IronOcr;

var ocr = new IronTesseract();

// Set primary language
ocr.Language = OcrLanguage.ChineseSimplified;

// Add secondary languages as needed
ocr.AddSecondaryLanguage(OcrLanguage.English);

// Custom .traineddata files can be added for specialized recognition
// ocr.AddSecondaryLanguage("path/to/custom.traineddata");

using (var input = new OcrInput())
{
    // Process multi-language document
    input.AddImage("img/MultiLanguage.jpeg");

    var result = ocr.Read(input);
    result.SaveAsTextFile("MultiLanguage.txt");
}
' Multi-language OCR configuration

Imports IronOcr



Private ocr = New IronTesseract()



' Set primary language

ocr.Language = OcrLanguage.ChineseSimplified



' Add secondary languages as needed

ocr.AddSecondaryLanguage(OcrLanguage.English)



' Custom .traineddata files can be added for specialized recognition

' ocr.AddSecondaryLanguage("path/to/custom.traineddata");



Using input = New OcrInput()

	' Process multi-language document

	input.AddImage("img/MultiLanguage.jpeg")



	Dim result = ocr.Read(input)

	result.SaveAsTextFile("MultiLanguage.txt")

End Using
$vbLabelText   $csharpLabel

How to Process Multi-Page Documents with C# OCR?

IronOCR seamlessly combines multiple pages or images into a single OcrResult. This feature enables powerful capabilities like creating searchable PDFs and extracting text from entire document sets.

Mix and match various sources - images, TIFF frames, and PDF pages - in a single OCR operation:

// Multi-source document processing
using IronOcr;

IronTesseract ocr = new IronTesseract();

using (OcrInput input = new OcrInput())
{
    // Add various image formats
    input.AddImage("image1.jpeg");
    input.AddImage("image2.png");

    // Process specific frames from multi-frame images
    int[] frameNumbers = { 1, 2 };
    input.AddImageFrames("image3.gif", frameNumbers);

    // Process all sources together
    OcrResult result = ocr.Read(input);

    // Verify page count
    Console.WriteLine($"{result.Pages.Count} Pages processed.");
}
// Multi-source document processing
using IronOcr;

IronTesseract ocr = new IronTesseract();

using (OcrInput input = new OcrInput())
{
    // Add various image formats
    input.AddImage("image1.jpeg");
    input.AddImage("image2.png");

    // Process specific frames from multi-frame images
    int[] frameNumbers = { 1, 2 };
    input.AddImageFrames("image3.gif", frameNumbers);

    // Process all sources together
    OcrResult result = ocr.Read(input);

    // Verify page count
    Console.WriteLine($"{result.Pages.Count} Pages processed.");
}
' Multi-source document processing

Imports IronOcr



Private ocr As New IronTesseract()



Using input As New OcrInput()

	' Add various image formats

	input.AddImage("image1.jpeg")

	input.AddImage("image2.png")



	' Process specific frames from multi-frame images

	Dim frameNumbers() As Integer = { 1, 2 }

	input.AddImageFrames("image3.gif", frameNumbers)



	' Process all sources together

	Dim result As OcrResult = ocr.Read(input)



	' Verify page count

	Console.WriteLine($"{result.Pages.Count} Pages processed.")

End Using
$vbLabelText   $csharpLabel

Process all pages of a TIFF file efficiently:

using IronOcr;

IronTesseract ocr = new IronTesseract();

using (OcrInput input = new OcrInput())
{
    // Define pages to process (0-based indexing)
    int[] pageIndices = new int[] { 0, 1 };

    // Load specific TIFF frames
    input.LoadImageFrames("MultiFrame.Tiff", pageIndices);

    // Extract text from all frames
    OcrResult result = ocr.Read(input);

    Console.WriteLine(result.Text);
    Console.WriteLine($"{result.Pages.Count} Pages processed");
}
using IronOcr;

IronTesseract ocr = new IronTesseract();

using (OcrInput input = new OcrInput())
{
    // Define pages to process (0-based indexing)
    int[] pageIndices = new int[] { 0, 1 };

    // Load specific TIFF frames
    input.LoadImageFrames("MultiFrame.Tiff", pageIndices);

    // Extract text from all frames
    OcrResult result = ocr.Read(input);

    Console.WriteLine(result.Text);
    Console.WriteLine($"{result.Pages.Count} Pages processed");
}
Imports IronOcr



Private ocr As New IronTesseract()



Using input As New OcrInput()

	' Define pages to process (0-based indexing)

	Dim pageIndices() As Integer = { 0, 1 }



	' Load specific TIFF frames

	input.LoadImageFrames("MultiFrame.Tiff", pageIndices)



	' Extract text from all frames

	Dim result As OcrResult = ocr.Read(input)



	Console.WriteLine(result.Text)

	Console.WriteLine($"{result.Pages.Count} Pages processed")

End Using
$vbLabelText   $csharpLabel

Convert TIFFs or PDFs to searchable formats:

using System;
using IronOcr;

IronTesseract ocr = new IronTesseract();

using (OcrInput input = new OcrInput())
{
    try
    {
        // Load password-protected PDF if needed
        input.LoadPdf("example.pdf", "password");

        // Process entire document
        OcrResult result = ocr.Read(input);

        Console.WriteLine(result.Text);
        Console.WriteLine($"{result.Pages.Count} Pages recognized");
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error processing PDF: {ex.Message}");
    }
}
using System;
using IronOcr;

IronTesseract ocr = new IronTesseract();

using (OcrInput input = new OcrInput())
{
    try
    {
        // Load password-protected PDF if needed
        input.LoadPdf("example.pdf", "password");

        // Process entire document
        OcrResult result = ocr.Read(input);

        Console.WriteLine(result.Text);
        Console.WriteLine($"{result.Pages.Count} Pages recognized");
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error processing PDF: {ex.Message}");
    }
}
Imports System

Imports IronOcr



Private ocr As New IronTesseract()



Using input As New OcrInput()

	Try

		' Load password-protected PDF if needed

		input.LoadPdf("example.pdf", "password")



		' Process entire document

		Dim result As OcrResult = ocr.Read(input)



		Console.WriteLine(result.Text)

		Console.WriteLine($"{result.Pages.Count} Pages recognized")

	Catch ex As Exception

		Console.WriteLine($"Error processing PDF: {ex.Message}")

	End Try

End Using
$vbLabelText   $csharpLabel

How to Create Searchable PDFs from Images?

IronOCR excels at creating searchable PDFs - a critical feature for database systems, SEO optimization, and document accessibility.

using IronOcr;

IronTesseract ocr = new IronTesseract();

using (OcrInput input = new OcrInput())
{
    // Set document metadata
    input.Title = "Quarterly Report";

    // Combine multiple sources
    input.AddImage("image1.jpeg");
    input.AddImage("image2.png");

    // Add specific frames from animated images
    int[] gifFrames = new int[] { 1, 2 };
    input.AddImageFrames("image3.gif", gifFrames);

    // Create searchable PDF
    OcrResult result = ocr.Read(input);
    result.SaveAsSearchablePdf("searchable.pdf");
}
using IronOcr;

IronTesseract ocr = new IronTesseract();

using (OcrInput input = new OcrInput())
{
    // Set document metadata
    input.Title = "Quarterly Report";

    // Combine multiple sources
    input.AddImage("image1.jpeg");
    input.AddImage("image2.png");

    // Add specific frames from animated images
    int[] gifFrames = new int[] { 1, 2 };
    input.AddImageFrames("image3.gif", gifFrames);

    // Create searchable PDF
    OcrResult result = ocr.Read(input);
    result.SaveAsSearchablePdf("searchable.pdf");
}
Imports IronOcr



Private ocr As New IronTesseract()



Using input As New OcrInput()

	' Set document metadata

	input.Title = "Quarterly Report"



	' Combine multiple sources

	input.AddImage("image1.jpeg")

	input.AddImage("image2.png")



	' Add specific frames from animated images

	Dim gifFrames() As Integer = { 1, 2 }

	input.AddImageFrames("image3.gif", gifFrames)



	' Create searchable PDF

	Dim result As OcrResult = ocr.Read(input)

	result.SaveAsSearchablePdf("searchable.pdf")

End Using
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Convert existing PDFs to searchable versions:

using IronOcr;

var ocr = new IronTesseract();

using (var input = new OcrInput())
{
    // Set PDF metadata
    input.Title = "Annual Report 2024";

    // Process existing PDF
    input.LoadPdf("example.pdf", "password");

    // Generate searchable version
    var result = ocr.Read(input);
    result.SaveAsSearchablePdf("searchable.pdf");
}
using IronOcr;

var ocr = new IronTesseract();

using (var input = new OcrInput())
{
    // Set PDF metadata
    input.Title = "Annual Report 2024";

    // Process existing PDF
    input.LoadPdf("example.pdf", "password");

    // Generate searchable version
    var result = ocr.Read(input);
    result.SaveAsSearchablePdf("searchable.pdf");
}
Imports IronOcr



Private ocr = New IronTesseract()



Using input = New OcrInput()

	' Set PDF metadata

	input.Title = "Annual Report 2024"



	' Process existing PDF

	input.LoadPdf("example.pdf", "password")



	' Generate searchable version

	Dim result = ocr.Read(input)

	result.SaveAsSearchablePdf("searchable.pdf")

End Using
$vbLabelText   $csharpLabel

Apply the same technique to TIFF conversions:

using IronOcr;

var ocr = new IronTesseract();

using (var input = new OcrInput())
{
    // Configure document properties
    input.Title = "Scanned Archive Document";

    // Select pages to process
    var pageIndices = new int[] { 1, 2 };
    input.LoadImageFrames("example.tiff", pageIndices);

    // Create searchable PDF from TIFF
    OcrResult result = ocr.Read(input);
    result.SaveAsSearchablePdf("searchable.pdf");
}
using IronOcr;

var ocr = new IronTesseract();

using (var input = new OcrInput())
{
    // Configure document properties
    input.Title = "Scanned Archive Document";

    // Select pages to process
    var pageIndices = new int[] { 1, 2 };
    input.LoadImageFrames("example.tiff", pageIndices);

    // Create searchable PDF from TIFF
    OcrResult result = ocr.Read(input);
    result.SaveAsSearchablePdf("searchable.pdf");
}
Imports IronOcr



Private ocr = New IronTesseract()



Using input = New OcrInput()

	' Configure document properties

	input.Title = "Scanned Archive Document"



	' Select pages to process

	Dim pageIndices = New Integer() { 1, 2 }

	input.LoadImageFrames("example.tiff", pageIndices)



	' Create searchable PDF from TIFF

	Dim result As OcrResult = ocr.Read(input)

	result.SaveAsSearchablePdf("searchable.pdf")

End Using
$vbLabelText   $csharpLabel

How to Export OCR Results as HOCR HTML?

IronOCR supports HOCR HTML export, enabling structured PDF to HTML and TIFF to HTML conversions while preserving layout information:

using IronOcr;

var ocr = new IronTesseract();

using (var input = new OcrInput())
{
    // Set HTML title
    input.Title = "Document Archive";

    // Process multiple document types
    input.AddImage("image2.jpeg");
    input.AddPdf("example.pdf", "password");

    // Add TIFF pages
    var pageIndices = new int[] { 1, 2 };
    input.AddTiff("example.tiff", pageIndices);

    // Export as HOCR with position data
    OcrResult result = ocr.Read(input);
    result.SaveAsHocrFile("hocr.html");
}
using IronOcr;

var ocr = new IronTesseract();

using (var input = new OcrInput())
{
    // Set HTML title
    input.Title = "Document Archive";

    // Process multiple document types
    input.AddImage("image2.jpeg");
    input.AddPdf("example.pdf", "password");

    // Add TIFF pages
    var pageIndices = new int[] { 1, 2 };
    input.AddTiff("example.tiff", pageIndices);

    // Export as HOCR with position data
    OcrResult result = ocr.Read(input);
    result.SaveAsHocrFile("hocr.html");
}
Imports IronOcr



Private ocr = New IronTesseract()



Using input = New OcrInput()

	' Set HTML title

	input.Title = "Document Archive"



	' Process multiple document types

	input.AddImage("image2.jpeg")

	input.AddPdf("example.pdf", "password")



	' Add TIFF pages

	Dim pageIndices = New Integer() { 1, 2 }

	input.AddTiff("example.tiff", pageIndices)



	' Export as HOCR with position data

	Dim result As OcrResult = ocr.Read(input)

	result.SaveAsHocrFile("hocr.html")

End Using
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Can IronOCR Read Barcodes Along with Text?

IronOCR uniquely combines text recognition with barcode reading capabilities, eliminating the need for separate libraries:

// Enable combined text and barcode recognition
using IronOcr;

var ocr = new IronTesseract();

// Enable barcode detection
ocr.Configuration.ReadBarCodes = true;

using (var input = new OcrInput())
{
    // Load image containing both text and barcodes
    input.AddImage("img/Barcode.png");

    // Process both text and barcodes
    var result = ocr.Read(input);

    // Extract barcode data
    foreach (var barcode in result.Barcodes)
    {
        Console.WriteLine($"Barcode Value: {barcode.Value}");
        Console.WriteLine($"Type: {barcode.Type}, Location: {barcode.Location}");
    }
}
// Enable combined text and barcode recognition
using IronOcr;

var ocr = new IronTesseract();

// Enable barcode detection
ocr.Configuration.ReadBarCodes = true;

using (var input = new OcrInput())
{
    // Load image containing both text and barcodes
    input.AddImage("img/Barcode.png");

    // Process both text and barcodes
    var result = ocr.Read(input);

    // Extract barcode data
    foreach (var barcode in result.Barcodes)
    {
        Console.WriteLine($"Barcode Value: {barcode.Value}");
        Console.WriteLine($"Type: {barcode.Type}, Location: {barcode.Location}");
    }
}
' Enable combined text and barcode recognition

Imports IronOcr



Private ocr = New IronTesseract()



' Enable barcode detection

ocr.Configuration.ReadBarCodes = True



Using input = New OcrInput()

	' Load image containing both text and barcodes

	input.AddImage("img/Barcode.png")



	' Process both text and barcodes

	Dim result = ocr.Read(input)



	' Extract barcode data

	For Each barcode In result.Barcodes

		Console.WriteLine($"Barcode Value: {barcode.Value}")

		Console.WriteLine($"Type: {barcode.Type}, Location: {barcode.Location}")

	Next barcode

End Using
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How to Access Detailed OCR Results and Metadata?

The IronOCR results object provides comprehensive data that advanced developers can leverage for sophisticated applications.

Each OcrResult contains hierarchical collections: pages, paragraphs, lines, words, and characters. All elements include detailed metadata like location, font information, and confidence scores.

Individual elements (paragraphs, words, barcodes) can be exported as images or bitmaps for further processing:

using System;
using IronOcr;
using IronSoftware.Drawing;

// Configure with barcode support
IronTesseract ocr = new IronTesseract
{
    Configuration = { ReadBarCodes = true }
};

using OcrInput input = new OcrInput();

// Process multi-page document
int[] pageIndices = { 1, 2 };
input.LoadImageFrames(@"img\Potter.tiff", pageIndices);

OcrResult result = ocr.Read(input);

// Navigate the complete results hierarchy
foreach (var page in result.Pages)
{
    // Page-level data
    int pageNumber = page.PageNumber;
    string pageText = page.Text;
    int pageWordCount = page.WordCount;

    // Extract page elements
    OcrResult.Barcode[] barcodes = page.Barcodes;
    AnyBitmap pageImage = page.ToBitmap();
    double pageWidth = page.Width;
    double pageHeight = page.Height;

    foreach (var paragraph in page.Paragraphs)
    {
        // Paragraph properties
        int paragraphNumber = paragraph.ParagraphNumber;
        string paragraphText = paragraph.Text;
        double paragraphConfidence = paragraph.Confidence;
        var textDirection = paragraph.TextDirection;

        foreach (var line in paragraph.Lines)
        {
            // Line details including baseline information
            string lineText = line.Text;
            double lineConfidence = line.Confidence;
            double baselineAngle = line.BaselineAngle;
            double baselineOffset = line.BaselineOffset;

            foreach (var word in line.Words)
            {
                // Word-level data
                string wordText = word.Text;
                double wordConfidence = word.Confidence;

                // Font information (when available)
                if (word.Font != null)
                {
                    string fontName = word.Font.FontName;
                    double fontSize = word.Font.FontSize;
                    bool isBold = word.Font.IsBold;
                    bool isItalic = word.Font.IsItalic;
                }

                foreach (var character in word.Characters)
                {
                    // Character-level analysis
                    string charText = character.Text;
                    double charConfidence = character.Confidence;

                    // Alternative character choices for spell-checking
                    OcrResult.Choice[] alternatives = character.Choices;
                }
            }
        }
    }
}
using System;
using IronOcr;
using IronSoftware.Drawing;

// Configure with barcode support
IronTesseract ocr = new IronTesseract
{
    Configuration = { ReadBarCodes = true }
};

using OcrInput input = new OcrInput();

// Process multi-page document
int[] pageIndices = { 1, 2 };
input.LoadImageFrames(@"img\Potter.tiff", pageIndices);

OcrResult result = ocr.Read(input);

// Navigate the complete results hierarchy
foreach (var page in result.Pages)
{
    // Page-level data
    int pageNumber = page.PageNumber;
    string pageText = page.Text;
    int pageWordCount = page.WordCount;

    // Extract page elements
    OcrResult.Barcode[] barcodes = page.Barcodes;
    AnyBitmap pageImage = page.ToBitmap();
    double pageWidth = page.Width;
    double pageHeight = page.Height;

    foreach (var paragraph in page.Paragraphs)
    {
        // Paragraph properties
        int paragraphNumber = paragraph.ParagraphNumber;
        string paragraphText = paragraph.Text;
        double paragraphConfidence = paragraph.Confidence;
        var textDirection = paragraph.TextDirection;

        foreach (var line in paragraph.Lines)
        {
            // Line details including baseline information
            string lineText = line.Text;
            double lineConfidence = line.Confidence;
            double baselineAngle = line.BaselineAngle;
            double baselineOffset = line.BaselineOffset;

            foreach (var word in line.Words)
            {
                // Word-level data
                string wordText = word.Text;
                double wordConfidence = word.Confidence;

                // Font information (when available)
                if (word.Font != null)
                {
                    string fontName = word.Font.FontName;
                    double fontSize = word.Font.FontSize;
                    bool isBold = word.Font.IsBold;
                    bool isItalic = word.Font.IsItalic;
                }

                foreach (var character in word.Characters)
                {
                    // Character-level analysis
                    string charText = character.Text;
                    double charConfidence = character.Confidence;

                    // Alternative character choices for spell-checking
                    OcrResult.Choice[] alternatives = character.Choices;
                }
            }
        }
    }
}
Imports System

Imports IronOcr

Imports IronSoftware.Drawing



' Configure with barcode support

Private ocr As New IronTesseract With {

	.Configuration = { ReadBarCodes = True }

}



Private OcrInput As using



' Process multi-page document

Private pageIndices() As Integer = { 1, 2 }

input.LoadImageFrames("img\Potter.tiff", pageIndices)



Dim result As OcrResult = ocr.Read(input)



' Navigate the complete results hierarchy

For Each page In result.Pages

	' Page-level data

	Dim pageNumber As Integer = page.PageNumber

	Dim pageText As String = page.Text

	Dim pageWordCount As Integer = page.WordCount



	' Extract page elements

	Dim barcodes() As OcrResult.Barcode = page.Barcodes

	Dim pageImage As AnyBitmap = page.ToBitmap()

	Dim pageWidth As Double = page.Width

	Dim pageHeight As Double = page.Height



	For Each paragraph In page.Paragraphs

		' Paragraph properties

		Dim paragraphNumber As Integer = paragraph.ParagraphNumber

		Dim paragraphText As String = paragraph.Text

		Dim paragraphConfidence As Double = paragraph.Confidence

		Dim textDirection = paragraph.TextDirection



		For Each line In paragraph.Lines

			' Line details including baseline information

			Dim lineText As String = line.Text

			Dim lineConfidence As Double = line.Confidence

			Dim baselineAngle As Double = line.BaselineAngle

			Dim baselineOffset As Double = line.BaselineOffset



			For Each word In line.Words

				' Word-level data

				Dim wordText As String = word.Text

				Dim wordConfidence As Double = word.Confidence



				' Font information (when available)

				If word.Font IsNot Nothing Then

					Dim fontName As String = word.Font.FontName

					Dim fontSize As Double = word.Font.FontSize

					Dim isBold As Boolean = word.Font.IsBold

					Dim isItalic As Boolean = word.Font.IsItalic

				End If



				For Each character In word.Characters

					' Character-level analysis

					Dim charText As String = character.Text

					Dim charConfidence As Double = character.Confidence



					' Alternative character choices for spell-checking

					Dim alternatives() As OcrResult.Choice = character.Choices

				Next character

			Next word

		Next line

	Next paragraph

Next page
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Summary

IronOCR provides C# developers with the most advanced Tesseract API implementation, running seamlessly across Windows, Linux, and Mac platforms. Its ability to accurately read text from image using IronOCR - even from imperfect documents - sets it apart from basic OCR solutions.

The library's unique features include integrated barcode reading and the ability to export results as searchable PDFs or HOCR HTML, capabilities unavailable in standard Tesseract implementations.

Moving Forward

To continue mastering IronOCR:

Source Code Download

Ready to implement C# OCR image to text conversion in your applications? Download IronOCR and start your free trial today.

Frequently Asked Questions

How do I fix low OCR accuracy on scanned documents?

Use IronOCR's image filters like Input.Deskew() and Input.DeNoise() to improve accuracy on low-quality scans. These filters correct rotation, remove noise, and enhance contrast, often improving accuracy from 95% to 99.8%.

What image formats are supported for OCR processing?

IronOCR supports all major image formats including PNG, JPEG, TIFF, BMP, and GIF. It also processes PDFs and multi-frame TIFF files, allowing you to mix different formats in a single OCR operation.

How can I speed up OCR processing for large documents?

Configure IronOCR with OcrLanguage.EnglishFast, use BlackListCharacters to exclude unnecessary symbols, and process specific regions using System.Drawing.Rectangle. These optimizations can improve speed by 35-41%.

Can I extract text from specific areas of an image?

Yes, use OcrInput.AddImage() with a System.Drawing.Rectangle parameter to define exact pixel coordinates for OCR processing. This is ideal for forms, invoices, and structured documents.

How do I handle documents with multiple languages?

Set the primary language using ocr.Language and add secondary languages with ocr.AddSecondaryLanguage(). IronOCR supports 125 languages through downloadable NuGet packages.

What's the difference between Read() and ReadAsync() methods?

The Read() method performs synchronous OCR processing, while ReadAsync() enables asynchronous operations for better application responsiveness when processing large documents or multiple files.

How can I export OCR results to different formats?

IronOCR provides multiple export methods: SaveAsSearchablePdf() for searchable PDFs, SaveAsHocrFile() for HOCR HTML with layout data, and SaveAsTextFile() for plain text output.

Why is my OCR failing on PDF files?

Ensure you're using LoadPdf() method with the correct password if the PDF is protected. For image-based PDFs, IronOCR automatically converts pages to images for processing. Check that the PDF isn't corrupted.

How do I access confidence scores for OCR results?

Each element in the OcrResult hierarchy (pages, paragraphs, lines, words, characters) has a Confidence property ranging from 0 to 1, indicating the recognition certainty.

Can I read both text and barcodes from the same document?

Yes, enable barcode reading with ocr.Configuration.ReadBarCodes = true. The OcrResult will contain both text content and a Barcodes collection with detected barcode values and types.

Jacob Mellor, Chief Technology Officer @ Team Iron
Jacob Mellor
  Chat with engineering team now
Chief Technology Officer

Jacob Mellor is Chief Technology Officer at Iron Software and a visionary engineer pioneering C# PDF technology. As the original developer behind Iron Software's core codebase, he has shaped the company's product architecture since its inception, transforming it alongside CEO Cameron Rimington into a 50+ person company serving NASA, Tesla, and global government agencies.

Jacob holds a First-Class Honours Bachelor of Engineering (BEng) in Civil Engineering from the University of Manchester (1998–2001). After opening his first software business in London in 1999 and creating his first .NET components in 2005, he specialized in solving complex problems across the Microsoft ecosystem.

His flagship IronPDF & IronSuite .NET libraries have achieved over 30 million NuGet installations globally, with his foundational code continuing to power developer tools used worldwide. With 25 years of commercial experience and 41 years of coding expertise, Jacob remains focused on driving innovation in enterprise-grade C#, Java, and Python PDF technologies while mentoring the next generation of technical leaders.

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