A pure-C# image processing library designed for image segmentation, color space conversions, and visual saliency map computation. It is fully generic, optimized, and has zero external dependencies on its core algorithms.

Features

Here is a comprehensive example demonstrating how to load an image, perform Gaussian blurring, segment it, and compute both global and regional visual saliency maps.

using System;
using SixLabors.ImageSharp;
using SixLabors.ImageSharp.PixelFormats;
using Leiter.Core;
using Leiter.Pixels;
using Leiter.Pixels.ColorSpaces;
using Leiter.Algorithms;
using Leiter.Algorithms.DataStructures;
using Leiter.Algorithms.Segmentation;
using Leiter.Algorithms.Saliency;
using Leiter.Platform.Linux; // Or Leiter.Platform.Windows on Windows

class Program
{
    static void Main()
    {
        // 1. Load an image using ImageSharp
        using var image = Image.Load<Rgb24>("input.png");
        
        // 2. Convert SixLabors Image to a generic Leiter Matrix
        Matrix<Rgb8> imageMatrix = image.ToSequentialMatrix();
        
        // 3. Smooth the image using Gaussian Blur
        Matrix<Rgb8> blurredImageMatrix = Blur.GaussianBlur(imageMatrix, 0.8f, 2);
        
        // 4. Convert colors to Lab32 color space for precise delta-E calculations
        var labImageMatrix = blurredImageMatrix.Map(pixel => pixel.ToLab32(RgbColorSpace.sRGB));
        
        // 5. Segment the image using EGBI (Felzenszwalb algorithm)
        IDisjointSet segmentationMatrix = EgbiSegmentation.Segment(labImageMatrix, kFactor: 50, minSegmentSize: 200);
        
        // 6. Color image by segments using the Average Color Assigner
        var imageSegmented = imageMatrix.Clone();
        EgbiSegmentation.ColorImageBySegmentation(
            imageSegmented, 
            segmentationMatrix.ToRegions(), 
            EgbiSegmentation.AverageColorAssigner()
        );
        using var segmentedImg = imageSegmented.ToImage();
        segmentedImg.Save("segmented.png");
        
        // 7. Compute Global Contrast Saliency Map
        var globalSaliencyMatrix = GlobalContrastSaliency.ComputeSaliency(imageMatrix);
        var globalSaliencyImageMatrix = globalSaliencyMatrix.Map(s => new Rgb8((byte)(s.Value * 255), (byte)(s.Value * 255), (byte)(s.Value * 255)));
        using var globalSaliencyImg = globalSaliencyImageMatrix.ToImage();
        globalSaliencyImg.Save("global_saliency.png");
        
        // 8. Compute Regional Contrast Saliency Map
        var regionalSaliencyMatrix = RegionalContrastSaliency.ComputeSaliency(imageMatrix, segmentationMatrix);
        var regionalSaliencyImageMatrix = regionalSaliencyMatrix.Map(s => new Rgb8((byte)(s.Value * 255), (byte)(s.Value * 255), (byte)(s.Value * 255)));
        using var regionalSaliencyImg = regionalSaliencyImageMatrix.ToImage();
        regionalSaliencyImg.Save("regional_saliency.png");
    }
}

Visual Saliency & Segmentation Showcase

Below is an actual example demonstrating the outputs of the library processing a studio-lit red tulip.

Library Architecture

License

This project is licensed under the MIT License - see the LICENSE.md file for details.