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 | |
| Typical 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(LightH,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 2 (H_MSG_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.
opening_circle is reentrant and automatically parallelized (on tuple level).
threshold, regiongrowing, connection, union1, watersheds, class_ndim_norm
reduce_domain, select_shape, area_center, connection
opening, dilation1, minkowski_add1, gen_circle
Morphology
