Finds the convex hull of a point set.
H = imconvexHull(contours[, cw[, ind]])
Contours in list
Return points in clockwise or counter-clockwise direction, 0 as CCW, 1 as CW
Return points in image rectangular coordinate pairs or the indices of contours, 0 to return coor pairs, 1 to return indexes
Convex hulls in list in correspond to the contours
The functions find the convex hull of all the contours in list using the Sklansky's algorithm.