Shape factor for the convexity of a region.
The operator convexity calculates the convexity of each input region of Regions.
Calculation: If $Fc$ is the area of the convex hull and $Fo$ the original area of the region the shape factor $C$ is defined as: C = Fo / Fc3cm C = F_{o}{F_{c}} description The shape factor C is 1 if the region is convex (e.g. rectangle, circle etc.). If there are indentations or holes C is smaller than 1. In case of an empty region the operator convexity returns the value 0 (if no other behavior was set (see set_system)). If more than one region is passed the numerical values of the contour length are stored in a tuple, the position of a value in the tuple corresponding to the position of the region in the input tuple.
Regions (input_object) |
region(-array) -> object |
Region(s) to be examined. |
Convexity (output_control) |
real(-array) -> real |
Convexity of the input region(s). | |
Assertion: Convexity <= 1 |
The operator convexity returns the value TRUE if the input is not empty. The behavior in case of empty input (no input regions available) is set via the operator set_system(::'no_object_result',<Result>:). The behavior in case of empty region (the region is the empty set) is set via set_system(::'empty_region_result',<Result>:). If necessary an exception is raised.
threshold__, regiongrowing__, connection
select_shape, area_center, shape_trans