CustomMeasurement

This class allows the creation of a new label analysis measurement, based on a user-defined formula.

A custom measurement is defined by a string formula that can invoke other measurements. It can be used by most of the individual analysis algorithms. It must have a unique name.

The formula defining a custom measurement must be written in accordance with the custom formula syntax. The validity of the formula can be verified with the checkMeasurementFormula method.

Notes

Even if it generally works, it is not recommended to create a new user measurement which depends on another user measurement, because it may not be as efficient as one might expect. The order of computation may also cause some problems.
A user-defined measurement cannot refer to an array of another measurement, except for distributions like FeretDiameter where the array is accessed through brackets.

See also

LabelAnalysis

AnalysisMsr::Ptr analysis = std::make_shared< AnalysisMsr >();
// Create a circularity factor between 0 and 1
std::string circularityFormula = "1.0/" + NativeMeasurements::inverseCircularity2d->name();
if ( checkMeasurementFormula( circularityFormula ) )
{
    const auto* customMeasurementInfo =
        AnalysisMsr::registerCustomMeasurement( "Circularity", circularityFormula, "This is my circularity factor." );
    auto circularity = analysis->select( customMeasurementInfo );
}
else
    std::cerr << "Invalid formula: " << circularityFormula << std::endl;

analysis = imagedev.AnalysisMsr()
# Create a circularity factor between 0 and 1
circularity_formula = "1.0/"+imagedev.native_measurements.InverseCircularity2d.name
if (imagedev.check_measurement_formula(circularity_formula)):
  custom_msr_info = imagedev.AnalysisMsr.register_custom_measurement("Circularity", circularity_formula, "This is my circularity factor.")
  circularity = analysis.select(custom_msr_info)
else:
  print(f"Invalid formula: {circularity_formula}")

AnalysisMsr analysis = new AnalysisMsr();
// Create a circularity factor between 0 and 1
String circularityFormula = "1.0/" + NativeMeasurements.InverseCircularity2d.name;
if (Processing.CheckMeasurementFormula(circularityFormula))
{
    var customMeasurementInfo =
        AnalysisMsr.RegisterCustomMeasurement("Circularity", circularityFormula, "This is my circularity factor.");
    var circularity = analysis.Select(customMeasurementInfo);
}
else
    Console.Error.WriteLine("Invalid formula: " + circularityFormula);