Operator Reference
moments_region_3rd (Operator)
moments_region_3rd — Geometric moments of regions.
Signature
Description
The operator moments_region_3rd calculates the
translation-invariant central moments (M21, M12,
M03, M30) of order p+q.
- Calculation:
-
x and y are the coordinates of the center of a region R with the area Z.
Then the moments are defined by:
,
wherein are .
If more than one region is passed the results are stored in tuples, the index of a value in the tuple corresponding to the index of a region in the input.
In case of empty region all parameters have the value 0.0 if no other
behavior was set (see set_system).
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
Regions (input_object) region(-array) → object
Regions to be examined.
M21 (output_control) real(-array) → (real)
Moment of 3rd order (line-dependent).
M12 (output_control) real(-array) → (real)
Moment of 3rd order (column-dependent).
M03 (output_control) real(-array) → (real)
Moment of 3rd order (column-dependent).
M30 (output_control) real(-array) → (real)
Moment of 3rd order (line-dependent).
Complexity
If Z is the area of the region the mean runtime complexity is O(sqrt(Z)).
Result
The operator moments_region_3rd returns the value 2 (
H_MSG_TRUE)
if the input is not empty.
The behavior in case of empty input (no input regions available) is
set via the operator set_system('no_object_result',<Result>).
The behavior in case of empty region (the region is the empty set) is set via
set_system('empty_region_result',<Result>).
If necessary an exception is raised.
Possible Predecessors
threshold,
regiongrowing,
connection
Alternatives
See also
Module
Foundation