9.40. Compute Moment Invariants (2D)
Group (Subgroup)
Statistics (Statistics)
Description
This Filter computes the 2D Omega-1 and Omega 2 values from the Central Moments matrix and optionally will normalize the values to a unit circle and also optionally save the Central Moments matrix as a DataArray to the Cell Feature Attribute Matrix. Based off the paper by MacSleyne et. al [1], the algorithm will calculate the 2D central moments for each feature starting at feature id = 1. Because feature id 0 is of special significance and typically is a matrix or background it is ignored in this filter. If any feature id has a Z Delta of > 1, the feature will be skipped. This algorithm works strictly in the XY plane and is meant to be applied to a 2D image. Using the research from the cited paper certain shapes can be detected using the Omega-1 and Omega-2 values. An example usage is finding elliptical shapes in an image:
See below figure from [1] that can help the user classify objects.


Input Cell Data
Parameter Name |
Parameter Type |
Parameter Notes |
Description |
|---|---|---|---|
2D Image Geometry |
Geometry Selection |
Image |
The path to the 2D image geometry to be used as input |
Cell Feature Ids |
Array Selection |
Allowed Types: int32 Comp. Shape: 1 |
Data Array that specifies to which Feature each Element belongs |
Feature Rect |
Array Selection |
Allowed Types: uint32 Comp. Shape: 6 |
Array holding the min xy and max xy pixel coordinates of each feature id |
Normalize Moment Invariants |
Bool |
Should the algorithm normalize the results to unit circle. |
Output Feature Data
Parameter Name |
Parameter Type |
Parameter Notes |
Description |
|---|---|---|---|
Feature Attribute Matrix |
AttributeMatrixSelection |
The path to the cell feature attribute matrix where the created data arrays will be stored |
|
Omega 1 |
DataObjectName |
Omega1 value |
|
Omega 2 |
DataObjectName |
Omega2 value |
|
Save Central Moments |
Bool |
Write the Central Moments to a new Data Array |
|
Central Moments |
DataObjectName |
Central Moments value |
9.41. Citations
[1] J.P. MacSleyne, J.P. Simmons, M. De Graef, On the use of 2-D moment invariants for the automated classification of particle shapes, Acta Materialia, Volume 56, Issue 3, February 2008, Pages 427-437, ISSN 1359-6454, http://dx.doi.org/10.1016/j.actamat.2007.09.039. http://www.sciencedirect.com/science/article/pii/S1359645407006702
9.42. Acknowledgements
The authors would like to thank Dr. Marc De Graef from Carnegie Mellon University for enlightening discussions and a concrete implementation from which to start this filter.
Example Pipelines
License & Copyright
Please see the description file distributed with this plugin.
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