NbPixels2d

Number of pixels in shape 2d measurement. More...

Classes
class	ipsdk::imaproc::shape::analysis::NbPixels2dMsr
	Measurement object for measure NbPixels2d. More...
class	ipsdk::imaproc::shape::analysis::NbPixels2dMsrInfo
	Information object for measure NbPixels2d. More...

Detailed Description

Number of pixels in shape 2d measurement.

NbPixels2d measure simply count number of pixels associated to a 2d shape.

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 number of pixels measurement :

Author

H. Delestre

Date

2015/07/07

Copyright

2015 Reactiv'IP, all right reserved.

Number of pixels in shape 2d measurement

Measure synthesis :

Measure Type	Measure Unit Type	Parameter Type	Result Type	Shape Requirements
Geometry 2d	None	None	Value (ipsdk::ipUInt64)	Row Intersections

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 NbPixels2d is not associated to any unit [ipsdk::shape::analysis::eMsrUnitFormat::eMUF_NoUnit]

Measure Parameter Type :

Measure NbPixels2d has no parameters

Measure Result Type :

Measure NbPixels2d is associated to ipsdk::shape::analysis::ValueMeasureResult<ipsdk::ipUInt64> results

Measure Shape Requirements :

Measure NbPixels2d requires row intersections from shape data

Measure Dependencies :

Measure NbPixels2d 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, "NbPixels2dMsr")
    
    #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("NbPixels2dMsr")
    
    # 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();
    BoolResult bCreateNbPixels2dMsr = pMeasureInfoSet->createMeasureInfo("NbPixels2dMsr");
    IPSDK_REQUIRE_MESSAGE(bCreateNbPixels2dMsr == true, bCreateNbPixels2dMsr.getMsg());

    // compute measure on shape 2d collection
    MeasureSetPtr pOutMeasureSet = shapeAnalysis2d(pInGreyImg2d, pShape2dColl, pMeasureInfoSet);

    // retrieve associated results
    const MeasureConstPtr& pNbPixels2dOutMsr = pOutMeasureSet->getMeasure("NbPixels2dMsr");
    const ValueMeasureResult<ipUInt64>& outResults = static_cast<const ValueMeasureResult<ipUInt64>&>(pNbPixels2dOutMsr->getMeasureResult());