Eccentricity2d

Measure eccentricity of the ellipse that has the same second moments as 2d shape. More...

Classes
class	ipsdk::imaproc::shape::analysis::Eccentricity2dMsr
	Measurement object for measure Eccentricity2d. More...
class	ipsdk::imaproc::shape::analysis::Eccentricity2dMsrInfo
	Information object for measure Eccentricity2d. More...

Detailed Description

Measure eccentricity of the ellipse that has the same second moments as 2d shape.

Eccentricity 2d measure computes the eccentricity of the ellipse that has the same second moments as 2d shape.

The eccentricity of the ellipse (commonly denoted as either or ) is given by :

where and are one-half of the ellipse's major and minor axes respectively (see InertiaLambdaMax and InertiaLambdaMin respectively).

Here is an example of eccentricity 2d measurement :

See also

http://en.wikipedia.org/wiki/Ellipse#Eccentricity

Author

E. Noirfalise

Date

2015/12/16

Copyright

2015 Reactiv'IP, all right reserved.

Measure eccentricity of the ellipse that has the same second moments as 2d shape

Measure synthesis :

Measure Type	Measure Unit Type	Parameter Type	Result Type	Shape Requirements
Generic	None	None	Value (ipsdk::ipReal64)	Row Intersections

See Shape measurement for additional information on these pictograms

Measure Type :

This is a generic measure

• it does not directly use shape or image data
• it can use dependencies to other measures to compute a result (see Measure Dependencies section)

This measure can only be used in 2d case

Measure Unit Type:

Measure Eccentricity2d is not associated to any unit [ipsdk::shape::analysis::eMsrUnitFormat::eMUF_NoUnit]

Measure Parameter Type :

Measure Eccentricity2d has no parameters

Measure Result Type :

Measure Eccentricity2d is associated to ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64> results

Measure Shape Requirements :

Measure Eccentricity2d requires row intersections from shape data

Measure Dependencies :

Measure Eccentricity2d depends on following measures :

Measure Mode	Measure Name	Measure Type	Measure Parameters
eMVP_2d	Inertia	Inertia2d

Note

See Shape Analysis 2d for more information on general shape 2d analysis and measurement usage.

Example of Python code :

Generic example in 2d case :

import PyIPSDK
import PyIPSDK.IPSDKIPLShapeAnalysis as shapeanalysis

    # Create the infoset
    inMeasureInfoSet2d = PyIPSDK.createMeasureInfoSet2d()
    PyIPSDK.createMeasureInfo(inMeasureInfoSet2d, "Eccentricity2dMsr")
    
    #Perform the analysis
    outMeasureSet = shapeanalysis.labelAnalysis2d(inGreyImg, inLabelImg2d, inMeasureInfoSet2d)
    
    # save results to csv format
    PyIPSDK.saveCsvMeasureFile(os.path.join(tmpPath,  "shape_analysis_results.csv"), outMeasureSet)
    
    # retrieve measure results
    outMsr = outMeasureSet.getMeasure("Eccentricity2dMsr")
    
    # retrieve measure values
    outMsrValues = outMsr.getMeasureResult().getColl(0)
    print("First label measurement equal " + str(outMsrValues[1]))

Example of C++ code :

Example informations

Associated library

IPSDKIPLShapeAnalysis

Code Example

    // opening grey level input image
    ImagePtr pInGreyImg2d = loadTiffImageFile(inputGreyImgPath);

    // read entity shape 2d collection used for processing
    Shape2dCollPtr pShape2dColl = boost::make_shared<Shape2dColl>();
    IPSDK_REQUIRE(readFromXmlFile(inputShape2dCollPath, *pShape2dColl) == true);

    // define a measure info set
    MeasureInfoSetPtr pMeasureInfoSet = MeasureInfoSet::create2dInstance();
    createMeasureInfo(pMeasureInfoSet, "Eccentricity2dMsr");
    
    // compute measure on shape 2d collection
    MeasureSetPtr pOutMeasureSet = shapeAnalysis2d(pInGreyImg2d, pShape2dColl, pMeasureInfoSet);

    // retrieve associated results
    const MeasureConstPtr& pEccentricity2dOutMsr = pOutMeasureSet->getMeasure("Eccentricity2dMsr");
    const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>& outResults = static_cast<const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>&>(pEccentricity2dOutMsr->getMeasureResult());