private Rect CalculateSquareRect(Mat[] contours)
{
if (contours.Length <= 1)
{
return(Rect.Empty);
}
Array.Sort(contours, (x, y) => y.ContourArea().CompareTo(x.ContourArea()));
Mat biggestContour = contours[1];
Mat approx = new Mat();
var epsilon = 0.1f * biggestContour.ArcLength(true);
Cv2.ApproxPolyDP(biggestContour, approx, epsilon, true);
Rect approxRect = Cv2.BoundingRect(approx);
float ar = approxRect.Width / (float)approxRect.Height;
Cv2.Rectangle(frame, approxRect, Scalar.Green, 2);
return(approxRect);
}
