Denotes how a bounding box is represented.
Represents the bounding box by using the combination of boundaries, {left, top, right, bottom}. The default order is {left, top, right, bottom}. Other orders can be indicated by an index array.
Represents the bounding box by using the center of the box, width and height. The default order is {center_x, center_y, width, height}. Other orders can be indicated by an index array.
Represents the bounding box by using the upper_left corner, width and height. The default order is {upper_left_x, upper_left_y, width, height}. Other orders can be indicated by an index array.