Compute the mean of Feret diameters over a range of uniformly distributed orientations.

MeanFeretDiameter measure computes the mean of Feret diameters measured on a shape over a uniform distribution of orientations. This measure is done on the polygonal (2d shapes) / polyhedral (3d shapes) approximations of the shapes. The number of orientations in the distribution can be specified by the user (it must be strictly greater than 0).

See FeretDiameter2d for more details about the 2d Feret diameters and FeretDiameter3d for more details about the 3d Feret diameters.

See MaxFeretDiameter for more details about way the uniformly distributed orientations are computed.

Here is an example of mean of Feret diameters measurement on a 2d shape with a number of orientations of 180:

mean of Feret diameters over the range of orientations [0; PI[

Measure synthesis :

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

See Shape measurement for additional information on these pictograms

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, "MeanFeretDiameterMsr")
    
    #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("MeanFeretDiameterMsr")
    
    # 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>();
    readFromXmlFile(inputShape2dCollPath, *pShape2dColl);
    // define a measure info set
    MeasureInfoSetPtr pMeasureInfoSet = MeasureInfoSet::create2dInstance();
    createMeasureInfo(pMeasureInfoSet, "MeanFeretDiameterMsr", createMeanFeretDiameterMsrParams(180));
    
    // compute measure on shape 2d collection
    MeasureSetPtr pOutMeasureSet = shapeAnalysis2d(pInGreyImg2d, pShape2dColl, pMeasureInfoSet);
    // retrieve associated results
    const MeasureConstPtr& pMeanFeretDiameterOutMsr = pOutMeasureSet->getMeasure("MeanFeretDiameterMsr");
    const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>& outResults = static_cast<const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>&>(pMeanFeretDiameterOutMsr->getMeasureResult());