Point location = new Point();
location.X = topleft.X;
location.Y = topleft.Y;
Size ze = new Size();
ze.Height = width;
ze.Height = height;
Rectangle rt = new Rectangle(location, ze);
MagickGeometry mgeomentory = new MagickGeometry(rt);
originalImage.Crop(mgeomentory);

List<AForge.IntPoint> corners = new List<AForge.IntPoint>();
corners.Add(new AForge.IntPoint(topleft.X, topleft.Y));
corners.Add(new AForge.IntPoint(topright.X, topright.Y));
corners.Add(new AForge.IntPoint(bottomright.X, bottomright.Y));
corners.Add(new AForge.IntPoint(bottomleft.X, bottomleft.Y));

SimpleQuadrilateralTransformation filter = new
SimpleQuadrilateralTransformation(corners, width, height);
Bitmap newImage = filter.Apply(originalImage);