Inertia3d

Measure allowing to compute the second order moment for 3d shape. More...

Classes
class	ipsdk::imaproc::shape::analysis::Inertia3dMsr
	Measurement object for measure Inertia3d. More...
class	ipsdk::imaproc::shape::analysis::Inertia3dMsrInfo
	Information object for measure Inertia3d. More...
class	ipsdk::imaproc::shape::analysis::Inertia3dMsrResults
	Measurement results object for measure Inertia3d. More...

Detailed Description

Measure allowing to compute the second order moment for 3d shape.

The Inertia3d measurement computes the second order central moment for each shape, without taking the pixels intensities into consideration.

It is equivalent to GreyInertia with all voxels intensities set to 1 in 3d case.

Here is an example of the inertia calculation :

See also

https://en.wikipedia.org/wiki/Image_moment#Central_moments

Author

H. Delestre

Date

2016/03/25

Copyright

2016 Reactiv'IP, all right reserved.

Measure allowing to compute the second order moment for 3d shape

Measure synthesis :

Measure Type	Measure Unit Type	Parameter Type	Result Type	Shape Requirements
Geometry 3d	None	None	Custom	Row Intersections

See Shape measurement for additional information on these pictograms

Measure Type :

This is a geometry 3d measure

• it use shape 3d data to compute a result
• it optionally can use dependencies to other measures to compute a result (see Measure Dependencies section)

This measure can only be used in 3d case

Measure Unit Type:

Measure Inertia3d is not associated to any unit [ipsdk::shape::analysis::eMsrUnitFormat::eMUF_NoUnit]

Measure Parameter Type :

Measure Inertia3d has no parameters

Measure Result Type :

Measure Inertia3d is associated to Inertia3dMsrResults results

Measure Shape Requirements :

Measure Inertia3d requires row intersections from shape data

Measure Dependencies :

Measure Inertia3d depends on following measures :

Measure Mode	Measure Name	Measure Type	Measure Parameters
eMVP_3d	Barycenter	Barycenter3d

Note

See Shape Analysis 3d for more information on general shape 3d analysis and measurement usage.

Example of Python code :

Generic example in 3d case :

import PyIPSDK
import PyIPSDK.IPSDKIPLShapeAnalysis as shapeanalysis

    # Create the infoset
    inMeasureInfoSet3d = PyIPSDK.createMeasureInfoSet3d()
    PyIPSDK.createMeasureInfo(inMeasureInfoSet3d, "Inertia3dMsr")
    
    #Perform the analysis
    outMeasureSet = shapeanalysis.labelAnalysis3d(inGreyImg, inLabelImg, inMeasureInfoSet3d)
    
    # save results to csv format
    PyIPSDK.saveCsvMeasureFile(os.path.join(tmpPath,  "shape_analysis_results.csv"), outMeasureSet)
    
    # retrieve measure results
    outMsr = outMeasureSet.getMeasure("Inertia3dMsr")
    
    # retrieve measure values
    outMsrValues = outMsr.getMeasureResult().getColl(0)
    print("First label inertia mxx component measurement equal " + str(outMsrValues[1].mxx()))

Example of C++ code :

Example informations

Associated library

IPSDKIPLShapeAnalysis

Code Example

    // opening grey level input image
    ImagePtr pInGreyImg3d = loadTiffImageFile(inputGreyImgPath);

    // read entity shape 3d collection used for processing
    Shape3dCollPtr pShape3dColl = boost::make_shared<Shape3dColl>();
    readFromBinaryFile(inputShape3dCollPath, *pShape3dColl);

    // define a measure info set
    MeasureInfoSetPtr pMeasureInfoSet = MeasureInfoSet::create3dInstance();
    createMeasureInfo(pMeasureInfoSet, "Inertia3dMsr");
    
    // compute measure on shape 3d collection
    MeasureSetPtr pOutMeasureSet = shapeAnalysis3d(pInGreyImg3d, pShape3dColl, pMeasureInfoSet);

    // retrieve associated results
    const MeasureConstPtr& pInertia3dOutMsr = pOutMeasureSet->getMeasure("Inertia3dMsr");
    const Inertia3dMsrResults& outResults = static_cast<const Inertia3dMsrResults&>(pInertia3dOutMsr->getMeasureResult());