How to use Iron Tesseract in C#

How Do I Create an IronTesseract Instance?

Initialize a Tesseract object with this code:

:path=/static-assets/ocr/content-code-examples/how-to/irontesseract-initialize-irontesseract.cs

using IronOcr;

IronTesseract ocr = new IronTesseract();

You can customize the behavior of IronTesseract by selecting different languages, enabling barcode reading, and whitelisting/blacklisting characters. IronOCR provides comprehensive configuration options to fine-tune your OCR process:

:path=/static-assets/ocr/content-code-examples/how-to/irontesseract-configure-irontesseract.cs

IronTesseract ocr = new IronTesseract
{
    Configuration = new TesseractConfiguration
    {
        ReadBarCodes = false,
        RenderHocr = true,
        TesseractVariables = null,
        WhiteListCharacters = null,
        BlackListCharacters = "`ë|^",
    },
    MultiThreaded = false,
    Language = OcrLanguage.English,
    EnableTesseractConsoleMessages = true, // False as default
};

Once configured, you can use Tesseract functionality to read OcrInput objects. The OcrInput class provides flexible methods for loading various input formats:

:path=/static-assets/ocr/content-code-examples/how-to/irontesseract-read.cs

IronTesseract ocr = new IronTesseract();

using OcrInput input = new OcrInput();
input.LoadImage("attachment.png");
OcrResult result = ocr.Read(input);
string text = result.Text;

For complex scenarios, you can leverage multithreading capabilities to process multiple documents simultaneously, significantly improving performance for batch operations.

What Are the Advanced Tesseract Configuration Variables?

The IronOcr Tesseract interface allows full control of Tesseract configuration variables through the IronOcr.TesseractConfiguration Class. These advanced settings enable you to optimize OCR performance for specific use cases, such as fixing low quality scans or reading specific document types.

:path=/static-assets/ocr/content-code-examples/how-to/irontesseract-tesseract-configuration.cs

using IronOcr;
using System;

IronTesseract Ocr = new IronTesseract();

Ocr.Language = OcrLanguage.English;
Ocr.Configuration.PageSegmentationMode = TesseractPageSegmentationMode.AutoOsd;

// Configure Tesseract Engine
Ocr.Configuration.TesseractVariables["tessedit_parallelize"] = false;

using var input = new OcrInput();
input.LoadImage("/path/file.png");

OcrResult Result = Ocr.Read(input);
Console.WriteLine(Result.Text);

// Example: Configure for financial documents
IronTesseract ocr = new IronTesseract
{
    Language = OcrLanguage.English,
    Configuration = new TesseractConfiguration
    {
        PageSegmentationMode = TesseractPageSegmentationMode.SingleBlock,
        TesseractVariables = new Dictionary<string, object>
        {
            ["tessedit_char_whitelist"] = "0123456789.$,",
            ["textord_heavy_nr"] = false,
            ["edges_max_children_per_outline"] = 10
        }
    }
};

// Apply preprocessing filters for better accuracy
using OcrInput input = new OcrInput();
input.LoadPdf("financial-document.pdf");
input.Deskew();
input.EnhanceResolution(300);

OcrResult result = ocr.Read(input);

// Example: Configure for financial documents
IronTesseract ocr = new IronTesseract
{
    Language = OcrLanguage.English,
    Configuration = new TesseractConfiguration
    {
        PageSegmentationMode = TesseractPageSegmentationMode.SingleBlock,
        TesseractVariables = new Dictionary<string, object>
        {
            ["tessedit_char_whitelist"] = "0123456789.$,",
            ["textord_heavy_nr"] = false,
            ["edges_max_children_per_outline"] = 10
        }
    }
};

// Apply preprocessing filters for better accuracy
using OcrInput input = new OcrInput();
input.LoadPdf("financial-document.pdf");
input.Deskew();
input.EnhanceResolution(300);

OcrResult result = ocr.Read(input);

What Is the Complete List of All Tesseract Configuration Variables?

These can be set using IronTesseract.Configuration.TesseractVariables["key"] = value;. The configuration variables allow you to fine-tune OCR behavior for optimal results with your specific documents. For detailed guidance on optimizing OCR performance, refer to our fast OCR configuration guide.

For best results, it's recommended to use IronOCR's image preprocessing filters before applying OCR. These filters can dramatically improve accuracy, especially when working with low quality scans or complex documents like tables.