ImageDev

Measurement Group

This example shows how to save a set of measurements in a file and reload it afterwards.
It may be useful to let a user of your application select a subset of measurements from all ImageDev measurements and allow him to recall this list each time the application is restarted.

In this case, you must store this list of measurements in a file and reload it when your application restarts.

This example simulates this situation and demonstrates that an analysis can be calculated from a saved list of measurements. 

#include <ImageDev/ImageDev.h>
#include <ioformat/IOFormat.h>
#include <string.h>

using namespace imagedev;
using namespace ioformat;
using namespace iolink;

int
main( int argc, char* argv[] )
{
    int status = 0;

    try
    {
        // ImageDev library initialization if not done
        if ( isInitialized() == false )
            imagedev::init();

        // Open a grayscale image from a tif file
        auto imageInput = readImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "objects.tif" );

        // Threshold and label the binary input
        auto imageBin = thresholdingByCriterion( imageInput,
                                                 ThresholdingByCriterion::ComparisonCriterion::GREATER_THAN_OR_EQUAL_TO,
                                                 40 );
        auto imageLab = labeling2d( imageBin, Labeling2d::LABEL_8_BIT, Labeling2d::CONNECTIVITY_8 );

        // Create a group of measurements
        MeasurementGroup::Ptr group = std::make_shared< MeasurementGroup >();
        group->add( NativeMeasurements::inverseCircularity2d );
        group->add( NativeMeasurements::feretDiameter2d );

        // Save this group and reload it
        group->write( "T04_04_group.xml" );
        MeasurementGroup::Ptr saved_group = std::make_shared< MeasurementGroup >();
        saved_group->read( "T04_04_group.xml" );

        // Define the analysis features to be computed
        AnalysisMsr::Ptr analysis = std::make_shared< AnalysisMsr >();
        analysis->select( saved_group->getMeasurements() );

        // Launch the feature extraction on the segmented image
        labelAnalysis( imageLab, imageInput, analysis );

        // Export the analysis in a dataframe and save it in a csv file
        auto dataframe = analysis->toDataFrame();
        writeView( dataframe, "T04_04_analysis.csv" );

        std::cout << "This example ran successfully." << std::endl;
    }
    catch ( const imagedev::Exception& error )
    {
        // Print potential exception in the standard output
        std::cerr << "T04_04_MeasurementGroup exception: " << error.what() << std::endl;
        status = -1;
    }

    // ImageDev library finalization
    imagedev::finish();

    // Check if we must ask for an enter key to close the program
    if ( !( ( argc == 2 ) && strcmp( argv[1], "--no-stop-at-end" ) == 0 ) )
        std::cout << "Press Enter key to close this window." << std::endl, getchar();

    return status;
}


See also