watersheds_threshold — Extract watershed basins from an image using a threshold.
The operator watersheds_threshold segments regions (basins)
that are separated from each other by a watershed that has a
height of at least Threshold.
In the first step, watersheds_threshold computes the watersheds
without applying a threshold, resulting in the same basins that would be
obtained when calling watersheds (for more details please refer to
the description of watersheds). In the second step, the basins are
successively merged if they are separated by a watershed that is smaller than
Threshold. Let and be the minimum
gray values of two neighboring basins and W the minimum gray value
of the watershed that separates the two basins. The watershed is eliminated
and the two basins are merged if
The thus obtained basins are returned in Basins.
If Threshold is set to 0, watersheds_threshold is
comparable to watersheds except that no watersheds but only expanded
basins are returned. If Threshold is set to the maximum gray value
range of Image then no two basins are separated by a watershed
exceeding Threshold, and hence, Basins will contain only
one region.
Image (input_object) singlechannelimage → object (byte / uint2 / real)
Image to be segmented.
Basins (output_object) region-array → object
Segments found (dark basins).
Threshold (input_control) number → (integer / real)
Threshold for the watersheds.
Default value: 10
Suggested values: 0, 5, 10, 20, 30, 50
Restriction: Threshold >= 0
watersheds always returns 2 (H_MSG_TRUE). The behavior with
respect to the input image and output regions can be determined by
setting the values of the flags 'no_object_result',
'empty_region_result', and 'store_empty_region'
with set_system. If necessary, an exception is raised.
binomial_filter,
gauss_filter,
smooth_image,
invert_image
expand_region,
select_shape,
reduce_domain,
opening
Foundation