The Recall function method returns the recall value from a confusion matrix, as an array with one value per class. Recall is the same as Producer Accuracy.


The code example below evaluates classifications using a confusion matrix.

PRO EvaluateClassificationUsingConfusionMatrix
    ; Start the application
    e = ENVI()
    ; Open an input file
    File = Filepath('qb_boulder_msi', Subdir=['data'], $
    Raster = e.OpenRaster(File)
    File2 = Filepath('qb_boulder_roi.xml', Subdir=['data'], $
    Rois = envi.OpenROI(roiFile)
    ; Get training statistics
    StatTask = ENVITask('ROIStatistics')
    StatTask.INPUT_RASTER = Raster
    StatTask.INPUT_ROI = Rois
    ; Get the task from the catalog of ENVITasks
    Task = ENVITask('MahalanobisDistanceClassification')
    ; Define inputs
    Task.INPUT_RASTER = Raster
    Task.COVARIANCE = StatTask.Covariance
    Task.MEAN = StatTask.Mean
    Task.CLASS_PIXEL_COUNT = StatTask.Roi_Pixel_Count
    Task.CLASS_NAMES = [Rois[0].name, Rois[1].name, Rois[2].name]
    Task.CLASS_COLORS = [[0,0,255], [0,255,0], [255,0,0]]
    ; Run the task and display the result
    ClassRaster = Task.OUTPUT_RASTER
    View = e.GetView()
    Layer = View.CreateLayer(ClassRaster)
    ; Add the output to the Data Manager
    envi.Data.Add, ClassRaster
    ; Calculate the confusion matrix
    ConfusionMatrix = ENVICalculateConfusionMatrixFromRaster(ClassRaster, Rois)
    ; Print results
    Print, 'Confusion Matrix:'
    Print, ConfusionMatrix.Confusion_Matrix
    Print, 'Errors of commission: '
    Print, Transpose([[ConfusionMatrix.Column_Names+': '], [(ConfusionMatrix.CommissionError()).ToString()]])
    Print, 'Errors of omission: '
    Print, Transpose([[ConfusionMatrix.Column_Names+': '], [(ConfusionMatrix.OmissionError()).ToString()]])
    Print, 'Overall accuracy: ', ConfusionMatrix.Accuracy()


Result = ENVIConfusionMatrix.Recall([, ERROR=variable])

Return Value

This function method returns a recall value from the confusion matrix.




ERROR (optional)

Set this keyword to a named variable that will contain any error message issued during execution of this routine. If no error occurs, the ERROR variable will be set to a null string (''). If an error occurs and the routine is a function, then the function result will be undefined.

When this keyword is not set and an error occurs, ENVI returns to the caller and execution halts. In this case, the error message is contained within !ERROR_STATE and can be caught using IDL's CATCH routine. See IDL Help for more information on !ERROR_STATE and CATCH.

See Manage Errors for more information on error handling in ENVI programming.

Version History

ENVI 5.4


API Version


See Also