Operator Reference
moments_region_2nd_invar (Operator)
moments_region_2nd_invar
— Geometric moments of regions.
Signature
Description
The operator moments_region_2nd_invar
calculates the
scaled moments (M20
, M02
)
and the product of inertia of the axes through the center parallel to the
coordinate axes (M11
).
- Calculation:
-
and are the coordinates of the center of a region R with the area F. Then the moments are defined by:
,
wherein Z and S run through all pixels of the region R.
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.
M11
(output_control) real(-array) →
(real)
Product of inertia of the axes through the center parallel to the coordinate axes.
M20
(output_control) real(-array) →
(real)
Moment of 2nd order (line-dependent).
M02
(output_control) real(-array) →
(real)
Moment of 2nd order (column-dependent).
Complexity
If F is the area of the region the mean runtime complexity is O(sqrt(F)).
Result
The operator moments_region_2nd_invar
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