Operator Reference
erosion_golay (Operator)
erosion_golay
— Erode a region with an element from the Golay alphabet.
Warning
erosion_golay
is obsolete and is only provided for
reasons of backward compatibility.
Signature
erosion_golay(Region : RegionErosion : GolayElement, Iterations, Rotation : )
Description
erosion_golay
erodes a region with the selected element
GolayElement
from the Golay alphabet. The following
structuring elements are available:
'l', 'm', 'd', 'c', 'e', 'i', 'f', 'f2', 'h', 'k'.
The rotation number Rotation
determines which rotation of
the element should be used, and whether the foreground (even) or
background version (odd) of the selected element should be used.
The Golay elements, together with all possible rotations, are
described with the operator golay_elements
. The
operator works by shifting the structuring element over the region
to be processed (Region
). For all positions of the
structuring element fully contained in the region, the
corresponding reference point (relative to the structuring element)
is added to the output region. This means that the intersection of
all translations of the structuring element within the region is
computed.
The parameter Iterations
determines the number of
iterations which are to be performed with the structuring element.
The result of iteration n-1 is used as input for iteration n.
Attention
Not all values of Rotation
are valid for any Golay
element. For some of the values of Rotation
, the
resulting regions are identical to the input regions.
Execution Information
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Automatically parallelized on tuple level.
Parameters
Region
(input_object) region(-array) →
object
Regions to be eroded.
RegionErosion
(output_object) region(-array) →
object
Eroded regions.
GolayElement
(input_control) string →
(string)
Structuring element from the Golay alphabet.
Default: 'h'
List of values: 'c' , 'd' , 'e' , 'f' , 'f2' , 'h' , 'i' , 'k' , 'l' , 'm'
Iterations
(input_control) integer →
(integer)
Number of iterations.
Default: 1
Suggested values: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 17, 20, 30, 40, 50
Value range:
1
≤
Iterations
(lin)
Minimum increment: 1
Recommended increment: 1
Rotation
(input_control) integer →
(integer)
Rotation of the Golay element. Depending on the element, not all rotations are valid.
Default: 0
List of values: 0, 2, 4, 6, 8, 10, 12, 14, 1, 3, 5, 7, 9, 11, 13, 15
Complexity
Let F be the area of an input region. Then the runtime complexity for one region is:
Result
erosion_golay
returns 2 (
H_MSG_TRUE)
if all parameters are
correct. The behavior in case of empty or no input region can be
set via:
-
empty region:
set_system('empty_region_result',<RegionResult>)
Otherwise, an exception is raised.
Possible Predecessors
threshold
,
regiongrowing
,
watersheds
,
class_ndim_norm
Possible Successors
reduce_domain
,
select_shape
,
area_center
,
connection
Alternatives
erosion_seq
,
erosion1
,
erosion2
See also
dilation_golay
,
opening_golay
,
closing_golay
,
hit_or_miss_golay
,
thinning_golay
,
thickening_golay
,
golay_elements
Module
Foundation