HomographySharp

HomographySharp is a (C#/.NET Standard2.0) class library for finding and using homography matrics.

Install

Package Manager

PM > Install-Package HomographySharp -Version 1.1.1

.NET CLI

dotnet add package HomographySharp --version 1.1.1

How to use

var srcList = new List<PointF>(4);
var dstList = new List<PointF>(4);

srcList.Add(new PointF { X = -152, Y = 394 });
srcList.Add(new PointF { X = 218, Y = 521 });
srcList.Add(new PointF { X = 223, Y = -331 });
srcList.Add(new PointF { X = -163, Y = -219 });

dstList.Add(new PointF { X = -666, Y = 431 });
dstList.Add(new PointF { X = 500, Y = 300 });
dstList.Add(new PointF { X = 480, Y = -308 });
dstList.Add(new PointF { X = -580, Y = -280 });

var homo = HomographyHelper.FindHomography(srcList, dstList);

(double x, double y) = HomographyHelper.Translate(homo, -152, 394);
Assert.IsTrue(Math.Abs(x - -666) < 0.001);
Assert.IsTrue(Math.Abs(y - 431) < 0.001);
            

or

var srcList = new List<DenseVector>(4);
var dstList = new List<DenseVector>(4);

srcList.Add(DenseVector.OfArray(new double[] { 10, 10 }));
srcList.Add(DenseVector.OfArray(new double[] { 100, 10 }));
srcList.Add(DenseVector.OfArray(new double[] { 100, 150 }));
srcList.Add(DenseVector.OfArray(new double[] { 10, 150 }));

dstList.Add(HomographyHelper.CreateVector2(11, 11));
dstList.Add(HomographyHelper.CreateVector2(500, 11));
dstList.Add(HomographyHelper.CreateVector2(500, 200));
dstList.Add(HomographyHelper.CreateVector2(11, 200));

var homo = HomographyHelper.FindHomography(srcList, dstList);// <-

(double dstX, double dstY) = HomographyHelper.Translate(homo, 100, 10);// <-

Assert.IsTrue(Math.Abs(dstX - 500) < 0.001);//true
Assert.IsTrue(Math.Abs(dstY - 11) < 0.001); //true

Visualize App

If you want to see how points are transformed by homography matrix, use this app.
https://github.com/nenoNaninu/HomographySharp/tree/master/HomographyVisualizer

External Library

• Math.NET Numerics
  • Copyright (c) 2002-2018 Math.NET
  • Released under the Math.NET Numerics License(MIT/X11)