Open a region with a circular structuring element.
opening_circle is defined as an erosion followed by a Minkowsi addition with a circular structuring element (see example). opening serves to eliminate small regions (smaller than the circular structuring element) and to smooth the boundaries of a region.
Region (input_object) |
region(-array) -> object |
Regions to be opened. |
RegionOpening (output_object) |
region(-array) -> object |
Opened regions. |
Radius (input_control) |
real -> real / integer |
Radius of the circular structuring element. | |
Default value: 3.5 | |
Suggested values: 1.5, 2.5, 3.5, 4.5, 5.5, 7.5, 9.5, 12.5, 15.5, 19.5, 25.5, 33.5, 45.5, 60.5, 110.5 | |
Range of values: 0.5 <= Radius <= 511.5 (lin) | |
Minimum increment: 1.0 | |
Recommended increment: 1.0 |
/* Large regions in an aerial picture (beech trees or meadows): */ read_image(:Image:'wald1':) > threshold__(Image:Light:80,255:) > /* close the small gap */ closing_circle(Light:H:2:) > /* selecting the large regions */ opening_circle(H:Large:20:).
Let F1 be the area of the input region. Then the runtime complexity for one region is:
O(4 * sqrt(F1) * Radius) .
opening_circle returns TRUE if all parameters are correct. The behavior in case of empty or no input region can be set via:
a) no region: set_system(::'no_object_result',<RegionResult>:) b) empty region: set_system(::'empty_region_result',<RegionResult>:)Otherwise, an exception is raised.
threshold__, regiongrowing__, connection, union1, watersheds, class_ndim1__
reduce_domain, select_shape, area_center, connection
opening, dilation1, minkowski_add1, circle