public override IObservable <Contours> Process(IObservable <Contours> source) { return(source.Select(input => { Seq output = input.FirstContour; if (output != null) { output = CV.ApproxPoly(output, Contour.HeaderSize, output.Storage, Method, Eps, Recursive); } return new Contours(output, input.ImageSize); })); }