Shape 2d area measurement (measure based on polygonal approximation)

Area2d measure is based on polygonal approximation of shapes. It computes area of polygons using Surveyor's triangulation algorithm.

Note that shape 2d area and number of pixels may differ since area is computed with respect to a given polygonal approximation while the number of pixels only take care of the initial image binary shape.

Here is an example of area 2d measurement :

Shape 2d area measurement (measure based on polygonal approximation)

Measure synthesis :

Measure Type	Measure Unit Type	Parameter Type	Result Type	Shape Requirements
Geometry 2d	Area	PolygonArea2dMsrParams	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, "AreaMinusHoles", "PolygonArea2dMsr", shapeanalysis.createHolesBasicPolicyMsrParams(True))
    PyIPSDK.createMeasureInfo(inMeasureInfoSet2d, "AreaWithHoles", "PolygonArea2dMsr", shapeanalysis.createHolesBasicPolicyMsrParams(False))
    
    #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
    outAreaMinusHolesMsr = outMeasureSet.getMeasure("AreaMinusHoles")
    outAreaWithHolesMsr = outMeasureSet.getMeasure("AreaWithHoles")
    
    # retrieve measure values
    outAreaWithHolesValues = outAreaWithHolesMsr.getMeasureResult().getColl(0)
    print("First label area with holes measurement equal " + str(outAreaWithHolesValues[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, "PolygonArea2dMsr", createHolesBasicPolicyMsrParams(bProcessHoles));
    
    // compute measure on shape 2d collection
    MeasureSetPtr pOutMeasureSet = shapeAnalysis2d(pInGreyImg2d, pShape2dColl, pMeasureInfoSet);
    // retrieve associated results
    const MeasureConstPtr& pPolygonArea2dOutMsr = pOutMeasureSet->getMeasure("PolygonArea2dMsr");
    const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>& outResults = static_cast<const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>&>(pPolygonArea2dOutMsr->getMeasureResult());