circularity_xld
— Shape factor for the circularity (similarity to a circle) of contours or
polygons.
circularity_xld(XLD : : : Circularity)
The operator circularity_xld
calculates the similarity of
each input contour or polygon with a circle. The input contour or polygon
must not intersect itself, otherwise the resulting parameter is not
meaningful (Whether the input contour or polygon intersects itself or not
can be determined with test_self_intersection_xld
). If
the input contour or polygon is not closed it will be closed automatically.
Calculation:
If F is the enclosed area of the contour or polygon and max is the
maximum distance from the center to all contour or polygon pixels, the
shape factor Circularity
is defined as:
The shape factor Circularity
of a circle is 1. If the contour
or polygon encloses an elongated area Circularity
is smaller than 1.
The operator circularity_xld
especially responds to large bulges.
If more than one contour or polygon is passed, the numerical values of the
shape factor are stored in a tuple in the same order as the respective
contours or polygons in XLD
.
XLD
(input_object) xld(-array) →
object
Contours or polygons to be examined.
Circularity
(output_control) real(-array) →
(real)
Roundness of the input contours or polygons.
Assertion: 0 <= Circularity && Circularity <= 1.0
The operator circularity_xld
returns the value 2 (H_MSG_TRUE)
if the input is not empty.
The behavior in case of empty input (no input contour available) is
set via the operator set_system('no_object_result',<Result>)
.
If necessary an exception is raised.
gen_contours_skeleton_xld
,
edges_sub_pix
,
threshold_sub_pix
,
gen_contour_polygon_xld
,
test_self_intersection_xld
compactness_xld
,
convexity_xld
,
eccentricity_xld
,
rectangularity_xld
area_center_xld
,
select_shape_xld
Foundation