PolygonArea2d

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

Classes
class	ipsdk::imaproc::shape::analysis::PolygonArea2dMsr
	Measurement object for measure PolygonArea2d. More...
class	ipsdk::imaproc::shape::analysis::PolygonArea2dMsrInfo
	Information object for measure PolygonArea2d. More...

Typedefs
typedef ipsdk::imaproc::shape::analysis::HolesBasicPolicyMsrParams	ipsdk::imaproc::shape::analysis::PolygonArea2dMsrParams
	parameters type associated to measure

Detailed Description

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 :

See also

https://en.wikipedia.org/wiki/Shoelace_formula

Author

R. Abbal

Date

2022/04/07

Copyright

2022 ReactivIP, all right reserved.

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

Measure Type :

This is a geometry 2d measure

• it use shape 2d data to compute a result
• it optionally 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 PolygonArea2d is associated to an area measurement unit [ipsdk::shape::analysis::eMsrUnitFormat::eMUF_AreaUnit]

Measure Parameter Type :

Measure PolygonArea2d is associated to PolygonArea2dMsrParams parameters

Measure Result Type :

Measure PolygonArea2d is associated to ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64> results

Measure Shape Requirements :

Measure PolygonArea2d requires boundary approximation from shape data

Measure Dependencies :

Measure PolygonArea2d has no dependency

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, "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());