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selectLabelsByGroup

Select ground truth labels by label group

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Syntax

gtLabel = selectLabelsByGroup(gTruth,labelGroups)

Description

gtLabel = selectLabelsByGroup(gTruth,labelGroups) selects labels belonging to the groups specified by labelGroups from a groundTruth object, gTruth. The function returns a corresponding groundTruth object, gtLabel, that contains only the selected labels. If gTruth is a vector of groundTruth objects, then the function returns a vector of corresponding groundTruth objects that contain only the selected labels.

example

Examples

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Open Live Script

Load data to create a ground truth object. Add the image folder to the path. 

data = load('stopSignsAndCars.mat');
imageFilenames = data.stopSignsAndCars.imageFilename(1:2)
imageFilenames = 2x1 cell
    {'stopSignImages/image001.jpg'}
    {'stopSignImages/image002.jpg'}


imageFilenames = fullfile(toolboxdir('vision'),'visiondata',imageFilenames);
dataSource = groundTruthDataSource(imageFilenames);

Define labels for identifying ground truth data.

names = {'stopSign';'carRear'};
types = [
    labelType('Rectangle')
    labelType('Rectangle')
    ];
groups = {'TrafficSigns';'Vehicles'};

labelDefs = table(names,types,groups,'VariableNames', {'Name','Type','Group'})
labelDefs=2×3 table
        Name          Type            Group      
    ____________    _________    ________________

    {'stopSign'}    Rectangle    {'TrafficSigns'}
    {'carRear' }    Rectangle    {'Vehicles'    }

Initialize label data for rectangle ROIs.

numRows = numel(imageFilenames);
stopSignTruth = {[856   318    39    41]; [445   523  52    54]};
carRearTruth = {[398   378   315   210]; [332   633   691   287]};

Construct a table containing label data.

labelData = table(stopSignTruth,carRearTruth,'VariableNames',names)
labelData=2×2 table
        stopSign               carRear      
    _________________    ___________________

    {[856 318 39 41]}    {[398 378 315 210]}
    {[445 523 52 54]}    {[332 633 691 287]}

Create a groundTruth object.

gTruth = groundTruth(dataSource,labelDefs,labelData)
gTruth = 
  groundTruth with properties:

          DataSource: [1x1 groundTruthDataSource]
    LabelDefinitions: [2x3 table]
           LabelData: [2x2 table]

Select labels by group.

vehicleGroundTruth = selectLabelsByGroup(gTruth, 'Vehicles')
vehicleGroundTruth = 
  groundTruth with properties:

          DataSource: [1x1 groundTruthDataSource]
    LabelDefinitions: [1x3 table]
           LabelData: [2x1 table]

Input Arguments

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Ground truth, specified as a groundTruth object or vector of groundTruth objects.

Label groups, specified as a character vector, string scalar, cell array of character vectors, or string vector.

To view all label groups in a groundTruth object, gTruth, enter this command at the MATLAB® command prompt.

unique(gTruth.LabelDefinitions.Group)

Example: 'Vehicles'

Example: "Vehicles"

Example: {'Vehicles','Signs'}

Example: ["Vehicles" "Signs"]

Output Arguments

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Ground truth with only the selected labels, returned as a groundTruth object or vector of groundTruth objects.

Each groundTruth object in gtLabel corresponds to a groundTruth object in the gTruth input. The returned objects contain only the labels belonging to the groups specified by the labelGroups input.

Version History

Introduced in R2019a

See Also

Objects

Functions