Return the union of all input regions.

union1 computes the union of all input regions and returns the result in RegionUnion.

/* Union of segmentation results: */
threshold(Image,Region1,128,255)
dyn_threshold(Image,Mean,Region2,5,'light')
concat_obj(Region1,Region2,Regions)
union1(Regions,RegionUnion).

Let F be the sum of all areas of the input regions. Then the runtime complexity is O(log(sqrt(F)) * sqrt(F)).

union1 always returns 2 (H_MSG_TRUE). The behavior in case of empty input (no regions given) can be set via set_system('no_object_result',<Result>) and the behavior in case of an empty input region via set_system('empty_region_result',<Result>). If necessary, an exception handling is raised.

union1 is reentrant and processed without parallelization.

threshold, connection, regiongrowing, pouring

select_shape, disp_region

union2

intersection, complement

Region processing