Compute, for a given orientation, Feret diameter (measure based on polyhedral approximation)

The 3d Feret diameter (also called "caliper diameter", referring to the measurement of an object size with a caliper) is a measure of the size of a 3d shape in a given direction (that will be described by 2 angles $\phi$ and $\theta$ ). The 2 angles $\phi$ and $\theta$ of the Feret diameter can be specified by the user. $\phi$ must belong to the range [0; $2*\pi$ [, and $\theta$ must belong to the range [0; $\pi$ ]

For more information about the definition of the 2 angles, report to "ConventionsPoints3d" section in the Core documentation

Here is an example of 3d Feret diameter measurement for $\phi=\theta=\pi$ :

computes, for a given orientation, Feret diameter

Measure synthesis :

Measure Type	Measure Unit Type	Parameter Type	Result Type	Shape Requirements
Generic	Length	FeretDiameter3dMsrParams	Value (ipsdk::ipReal64)	Boundary Approximation

See Shape measurement for additional information on these pictograms

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, "FeretDiameter3dMsr")
    
    #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("FeretDiameter3dMsr")
    
    # 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 pInGreyImg3d = loadTiffImageFile(inputGreyImgPath, eTiffDirectoryMode::eTDM_Volume);
    // 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, "FeretDiameter3dMsr", createFeretDiameter3dMsrParams(phi, theta));
    
    // compute measure on shape 3d collection
    MeasureSetPtr pOutMeasureSet = shapeAnalysis3d(pInGreyImg3d, pShape3dColl, pMeasureInfoSet);
    // retrieve associated results
    const MeasureConstPtr& pFeretDiameter3dOutMsr = pOutMeasureSet->getMeasure("FeretDiameter3dMsr");
    const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>& outResults = static_cast<const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>&>(pFeretDiameter3dOutMsr->getMeasureResult());