import numpy
triangle = numpy.array([ [100,300], [400,800],[200,500] ], numpy.int32)#[1，3]，[4，8],[1,9]为要填充的轮廓坐标
cv2.fillConvexPoly(image, triangle, (0, 0, 255))
cv2.imshow("fff", image)
cv2.waitKey (0)
cv2.destroyAllWindows()
原文：https://www.cnblogs.com/lhuser/p/13733257.html