computation of distance to nearest neighbor for each shape

This measure allows to compute the distance to the nearest neighbor for each shape. It is based on a geometric analysis of the shape neighborhood.

A polygonal approximation of shapes is used to compute the distances between shapes.

The parameter flag ProcessHoles allows to specify whether shape holes should be taken into account during computation :

In the previous figure :

stands for inter-shape distance computed while ignoring holes
stands for inter-shape distance computed while taking care of holes

Here is an example of nearest neighbor computation for several shapes :

In the previous figure shapes (ie. the polygonal approximation of boundaries), are colored with respect to the computed distance to its nearest neighbor.

computation of distance to nearest neighbor for each shape

Measure synthesis :

Measure Type	Measure Unit Type	Parameter Type	Result Type	Shape Requirements
Geometry 2d	Length	DistanceToNearestNeighbor2dMsrParams	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, "DistanceToNearestNeighbor2dMsr")
    
    #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("DistanceToNearestNeighbor2dMsr")
    
    # 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, "DistanceToNearestNeighbor2dMsr", createHolesBasicPolicyMsrParams(bProcessHoles));
    
    // compute measure on shape 2d collection
    MeasureSetPtr pOutMeasureSet = shapeAnalysis2d(pInGreyImg2d, pShape2dColl, pMeasureInfoSet);
    // retrieve associated results
    const MeasureConstPtr& pDistanceToNearestNeighbor2dOutMsr = pOutMeasureSet->getMeasure("DistanceToNearestNeighbor2dMsr");
    const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>& outResults = static_cast<const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>&>(pDistanceToNearestNeighbor2dOutMsr->getMeasureResult());