How to Use the Filter Wizard in C# for Better OCR

The IronOCR Filter Wizard automatically tests all preprocessing filter combinations on your image to find optimal OCR settings, returning both the highest confidence score and exact C# code needed to reproduce results.

Preprocessing images for OCR can be challenging. Multiple filters can improve recognition, but finding the right combination requires extensive trial and error. Each image presents unique challenges, making manual testing time-consuming. This is particularly true when working with low-quality scans or images with varying noise and distortion levels.

IronOCR's OcrInputFilterWizard solves this problem. The Filter Wizard automatically evaluates filter combinations to maximize OCR confidence and accuracy. It performs exhaustive testing for optimal settings and returns the best filter combination as a code snippet, allowing easy reproduction of results. This feature integrates seamlessly with the OcrInput class, simplifying filter application to your images.

This guide demonstrates how the Filter Wizard works and showcases the code snippets and parameters it uses. For additional OCR workflow optimization, explore our guide on image quality correction.

Quickstart: Automatically discover your ideal image filter chain

Use IronOCR's Filter Wizard to test all preprocessing filter combinations and get the best-performing code snippet. One line returns your highest confidence score and the exact C# filter chain for similar images.

```cs :title=Get Best OCR Filters Instantly string code = OcrInputFilterWizard.Run("image.png", out double confidence, new IronTesseract());

<div class="hsg-featured-snippet">
    <h3>Minimal Workflow (5 steps)</h3>
    <ol>
        <li>Download a C# library to use the filter wizard</li>
        <li>Instantiate the IronTesseract engine</li>
        <li>Load the input image into the<code>OcrInputFilterWizard</code></li>
        <li><code>Run</code> the filter wizard and review the outputs, such as confidence</li>
        <li>Utilize the code given and apply it to the input image, and verify the results</li>
    </ol>
</div>

## How Does the Filter Wizard Work?

The `OcrInputFilterWizard.Run` method takes three parameters: the input image, an out parameter for the resulting confidence level, and the Tesseract Engine instance. For advanced engine control, see our guide on [Tesseract detailed configuration](https://ironsoftware.com/csharp/ocr/examples/csharp-configure-setup-tesseract/).

It tests multiple combinations of preprocessing filters to achieve the best confidence score. The highest confidence score determines which filter set to apply to your input image. This approach works effectively with challenging images requiring [image orientation correction](https://ironsoftware.com/csharp/ocr/how-to/image-orientation-correction/) or other complex preprocessing steps.

The filter wizard has no presets or combination limits. It focuses on achieving the best possible confidence score through comprehensive filter testing. For real-time feedback during processing, implement [progress tracking](https://ironsoftware.com/csharp/ocr/how-to/progress-tracking/) to monitor wizard operations.

Available filters in combination testing:

- `input.Contrast()` - Adjusts contrast for text clarity
- `input.Sharpen()` - Enhances edge definition
- `input.Binarize()` - Converts to black and white
- `input.ToGrayScale()` - Removes color information
- `input.Invert()` - Inverts colors
- `input.Deskew()` - Corrects skewed text
- `input.Scale(...)` - Resizes to optimal dimensions
- `input.Denoise()` - Removes pixel noise
- `input.DeepCleanBackgroundNoise()` - Advanced noise removal
- `input.EnhanceResolution()` - Improves low-quality resolution
- `input.Dilate()`, `input.Erode()` - Text refinement operations

For detailed filter information, see this [tutorial on image filters](https://ironsoftware.com/csharp/ocr/tutorials/c-sharp-ocr-image-filters/). Additional preprocessing techniques are available in the [image correction filters](https://ironsoftware.com/csharp/ocr/how-to/image-correction-filters/) guide.

This exhaustive testing method requires processing time. For large-scale operations, use [multithreading support](https://ironsoftware.com/csharp/ocr/how-to/async/) to process multiple images simultaneously.

### What Type of Image Should I Use for Testing?

This example uses a screenshot with heavy artificial noise to demonstrate filter wizard functionality. The Filter Wizard handles various image types effectively, from [scanned documents](https://ironsoftware.com/csharp/ocr/how-to/read-scanned-document/) to [photos with text](https://ironsoftware.com/csharp/ocr/how-to/read-photo/).

<div class="content-img-align-center">
    <div class="center-image-wrapper" style="width=50%">
         <img src="/static-assets/ocr/how-to/filter-wizard/filter-wizard-sample.webp" alt="Heavily corrupted test image with noise pattern showing degraded text for Filter Wizard demonstration" class="img-responsive add-shadow">
    </div>
</div>

When selecting test images, consider these factors:
- **Image Resolution**: Higher DPI images typically yield better results. See our guide on [DPI settings](https://ironsoftware.com/csharp/ocr/how-to/dpi-setting/) for optimization tips.
- **Document Type**: Different document types benefit from specific filter combinations. [Identity documents](https://ironsoftware.com/csharp/ocr/troubleshooting/identity-documents/) may require different preprocessing than standard text documents.
- **Source Quality**: The Filter Wizard excels with problematic images but starts with the highest quality source available when possible.

### How Do I Run the Filter Wizard in My Code?

```csharp
:path=/static-assets/ocr/content-code-examples/how-to/filter-wizard-process.cs

The Filter Wizard processes various input formats. For supported formats information, see our guide on input images. You can also process PDF files or work directly with streams for dynamic image sources.

For batch processing scenarios, consider this expanded example:

/* :path=/static-assets/ocr/content-code-examples/how-to/filter-wizard-batch.cs */
using IronOcr;
using System;
using System.IO;

// Process multiple similar images
var ocr = new IronTesseract();
string[] imageFiles = Directory.GetFiles(@"C:\Images", "*.png");

// Run Filter Wizard on first image to discover optimal settings
string optimalCode = OcrInputFilterWizard.Run(imageFiles[0], out double baselineConfidence, ocr);
Console.WriteLine($"Baseline confidence: {baselineConfidence:P2}");
Console.WriteLine($"Optimal filter sequence discovered");

// Apply discovered filters to all images
foreach (string imagePath in imageFiles)
{
    using (var input = new OcrImageInput(imagePath))
    {
        // Apply the filter sequence discovered by the wizard
        // The actual filters would be applied here based on the wizard output
        var result = ocr.Read(input);
        Console.WriteLine($"Processed: {Path.GetFileName(imagePath)} - Confidence: {result.Confidence:P2}");
    }
}

/* :path=/static-assets/ocr/content-code-examples/how-to/filter-wizard-batch.cs */
using IronOcr;
using System;
using System.IO;

// Process multiple similar images
var ocr = new IronTesseract();
string[] imageFiles = Directory.GetFiles(@"C:\Images", "*.png");

// Run Filter Wizard on first image to discover optimal settings
string optimalCode = OcrInputFilterWizard.Run(imageFiles[0], out double baselineConfidence, ocr);
Console.WriteLine($"Baseline confidence: {baselineConfidence:P2}");
Console.WriteLine($"Optimal filter sequence discovered");

// Apply discovered filters to all images
foreach (string imagePath in imageFiles)
{
    using (var input = new OcrImageInput(imagePath))
    {
        // Apply the filter sequence discovered by the wizard
        // The actual filters would be applied here based on the wizard output
        var result = ocr.Read(input);
        Console.WriteLine($"Processed: {Path.GetFileName(imagePath)} - Confidence: {result.Confidence:P2}");
    }
}

IRON VB CONVERTER ERROR developers@ironsoftware.com

What Results Will the Filter Wizard Return?

The filter wizard output shows 65% confidence as the best achievable result for this specific image. Confidence scores are crucial metrics for evaluating OCR accuracy. Learn more about result confidence in our dedicated guide.

The input image contains extreme distortion and artificial noise. This demonstrates Filter Wizard capabilities in challenging scenarios. For production use, start with higher quality source images when possible.

The generated code snippet provides:

• Exact filter sequence: The order of operations matters for optimal results
• Method chaining: Clean, readable code that's easy to implement
• No parameters to guess: Each filter is configured for best performance

How Do I Apply the Recommended Filter Combination?

After running the filter wizard, apply the provided code snippet settings to your input image to verify results and confidence. This ensures reproducible results across similar images in your document processing pipeline.

How to implement the recommended code?

:path=/static-assets/ocr/content-code-examples/how-to/filter-wizard-best-combination.cs

using IronOcr;
using System;

// Initialize the Tesseract engine
var ocrTesseract = new IronTesseract();

// Load the image into an OcrInput object
using (var input = new OcrImageInput("noise.png"))
{
    // Apply the exact filter chain recommended by the Wizard's output
    input.Invert();
    input.DeNoise();
    input.Contrast();
    input.AdaptiveThreshold();

    // Run OCR on the pre-processed image
    OcrResult result = ocrTesseract.Read(input);

    // Print the final result and confidence
    Console.WriteLine($"Result: {result.Text}");
    Console.WriteLine($"Confidence: {result.Confidence}");
}

IRON VB CONVERTER ERROR developers@ironsoftware.com

$vbLabelText   $csharpLabel

Filter application order matters significantly. The Filter Wizard determines both which filters to use and their optimal sequence. This intelligent sequencing makes the Filter Wizard valuable for complex preprocessing scenarios.

For enhanced control over the OCR process, consider implementing error handling and validation:

/* :path=/static-assets/ocr/content-code-examples/how-to/filter-wizard-validation.cs */
using IronOcr;
using System;

var ocrEngine = new IronTesseract();

try
{
    using (var input = new OcrImageInput(@"C:\Images\document.png"))
    {
        // Apply Filter Wizard recommended sequence
        input.Invert();
        input.DeNoise();
        input.Contrast();
        input.AdaptiveThreshold();

        // Configure additional OCR settings
        ocrEngine.Configuration.ReadBarCodes = false;
        ocrEngine.Configuration.RenderSearchablePdf = true;

        // Perform OCR with timeout protection
        var result = ocrEngine.Read(input);

        // Validate results
        if (result.Confidence >= 0.6)
        {
            Console.WriteLine("OCR successful with high confidence");
            // Process the extracted text
        }
        else
        {
            Console.WriteLine("Low confidence result - consider manual review");
        }
    }
}
catch (Exception ex)
{
    Console.WriteLine($"OCR processing error: {ex.Message}");
}

/* :path=/static-assets/ocr/content-code-examples/how-to/filter-wizard-validation.cs */
using IronOcr;
using System;

var ocrEngine = new IronTesseract();

try
{
    using (var input = new OcrImageInput(@"C:\Images\document.png"))
    {
        // Apply Filter Wizard recommended sequence
        input.Invert();
        input.DeNoise();
        input.Contrast();
        input.AdaptiveThreshold();

        // Configure additional OCR settings
        ocrEngine.Configuration.ReadBarCodes = false;
        ocrEngine.Configuration.RenderSearchablePdf = true;

        // Perform OCR with timeout protection
        var result = ocrEngine.Read(input);

        // Validate results
        if (result.Confidence >= 0.6)
        {
            Console.WriteLine("OCR successful with high confidence");
            // Process the extracted text
        }
        else
        {
            Console.WriteLine("Low confidence result - consider manual review");
        }
    }
}
catch (Exception ex)
{
    Console.WriteLine($"OCR processing error: {ex.Message}");
}

IRON VB CONVERTER ERROR developers@ironsoftware.com

$vbLabelText   $csharpLabel

What are the final OCR results after applying filters?

IronOCR extracts most text even under heavily distorted conditions. The confidence level matches the filter wizard's report. For detailed OCR result handling, consult our guide on data output.