Is there any built-in function to draw rectangle on tracked objects?

Question

After some HSV correction, erosion and dilation using trackbars, contours are generated using

findContours(hsv, contours, RETR_TREE, CHAIN_APPROX_SIMPLE);

and then in a sequential loop

for (int i = 0; i < contours.size(); i++) {
    bound = boundingRect(contours[i]);
    if (bound.area() > 1000 && bound.area() < 2000)
        rectangle(cam, bound.tl(), bound.br(), color);
}

rectangles are drawn on screen.

Is there any built in function to do it in parallel or without using sequential loop?