Outline slope angularity 2d

this measure allows to compute changes in the slope of the shape outline More...

Classes
class	ipsdk::imaproc::shape::analysis::OutlineSlopeAngularity2dMsr
	Measurement object for measure OutlineSlopeAngularity2d. More...
class	ipsdk::imaproc::shape::analysis::OutlineSlopeAngularity2dMsrInfo
	Information object for measure OutlineSlopeAngularity2d. More...
class	ipsdk::imaproc::shape::analysis::OutlineSlopeAngularity2dMsrParams
	Parameter object for measure OutlineSlopeAngularity2d. More...

Detailed Description

this measure allows to compute changes in the slope of the shape outline

This measure allows to quantified the angularity using the changes in the slope of of a shape outline.

For each tops of the polygonal approximation of shape, we compute an intermediate value given by :

where :

• is angle between segments ending at considered top .
  

We then compute the histogram of these values using a number of orientation defined by parameter NbOrientations.

The global shape angularity value is then given by following formula :

where :

• is the requested number of orientations for histogram analysis (ie. parameter NbOrientations).
• is the angle associated to center of class .
• is the probability associated to class .

Here is an example of degree of angularity 2d computation on few caracteristic shapes :

See also

Rao, C., Tutumluer, E. and Kim, I. T. (2002). Quantification of coarse aggregate angularity based on image analysis. In Transportation Research Record, Journal of the Transportation Research Board, No. 1787, Washington, D.C, pp. 117-124.

Lees, G. (1964) A new method for determining the angularity of particles. Sedimentology, 3, pp. 2-21.

Taleb Al-Rousan, Eyad Masad, Erol Tutumluer, Tongyan Pan, Evaluation of image analysis techniques for quantifying aggregate shape characteristics, Construction and Building Materials 21 (2007) 978-990.

Tafesse Solomon, Sun Wenjuan, Fernlund Joanne, and Linbing Wang, A new image analysis technique to quantify particle angularity, Engineering Geology and Geophysics Research Group Royal Institute of Technology (KTH)

Moaveni, Wang, Hart, Tutumluer, and Ahuja , Aggregate size and shape evaluation using segmentation techniques and aggregate image processing algorithms, Transportation Research Board Washington, DC, January 2013

Author

E.Noirfalise

Date

2017/07/21

Copyright

2017 Reactiv'IP, all right reserved.

this measure allows to compute changes in the slope of the shape outline

Measure synthesis :

Measure Type	Measure Unit Type	Parameter Type	Result Type	Shape Requirements
Geometry 2d	Angle	OutlineSlopeAngularity2dMsrParams	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 OutlineSlopeAngularity2d is associated to an angular (radians) measurement unit [ipsdk::shape::analysis::eMsrUnitFormat::eMUF_RadianUnit]

Measure Parameter Type :

Measure OutlineSlopeAngularity2d is associated to OutlineSlopeAngularity2dMsrParams parameters

Measure Result Type :

Measure OutlineSlopeAngularity2d is associated to ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64> results

Measure Shape Requirements :

Measure OutlineSlopeAngularity2d requires boundary approximation from shape data

Measure Dependencies :

Measure OutlineSlopeAngularity2d 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, "OutlineSlopeAngularity2dMsr")
    
    #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("OutlineSlopeAngularity2dMsr")
    
    # 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, "OutlineSlopeAngularity2dMsr");
    
    // compute measure on shape 2d collection
    MeasureSetPtr pOutMeasureSet = shapeAnalysis2d(pInGreyImg2d, pShape2dColl, pMeasureInfoSet);

    // retrieve associated results
    const MeasureConstPtr& pOutlineSlopeAngularity2dOutMsr = pOutMeasureSet->getMeasure("OutlineSlopeAngularity2dMsr");
    const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>& outResults = static_cast<const ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipReal64>&>(pOutlineSlopeAngularity2dOutMsr->getMeasureResult());