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selectLabelsByLabelType

Select multisignal ground truth by label type

Description

example

gtLabel = selectLabelsByLabelType(gTruth,labelTypes) selects labels of the types specified by labelTypes from a groundTruthMultisignal object, gTruth. The function returns a corresponding groundTruthMultisignal object, gtLabel, that contains only the selected labels. If gTruth is a vector of groundTruthMultisignal objects, then the function returns a vector of corresponding groundTruthMultisignal objects that contain only the selected labels.

Examples

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Select ground truth labels from a groundTruthMultisignal object by specifying a label type.

Load a groundTruthMultisignal object containing ROI and scene label data for a video and corresponding lidar point cloud sequence. The helper function used to load this object is attached to the example as a supporting file.

gTruth = helperLoadGTruthVideoLidar;

Inspect the label definitions. The object contains definitions for rectangle, cuboid, and scene label types.

gTruth.LabelDefinitions
ans =

  5x7 table

      Name       SignalType    LabelType       Group        Description     LabelColor      Hierarchy  
    _________    __________    _________    ____________    ___________    ____________    ____________

    {'car'  }    Image         Rectangle    {'Vehicles'}    {0x0 char}     {1x3 double}    {1x1 struct}
    {'car'  }    PointCloud    Cuboid       {'Vehicles'}    {0x0 char}     {1x3 double}    {1x1 struct}
    {'truck'}    Image         Rectangle    {'Vehicles'}    {0x0 char}     {1x3 double}    {0x0 double}
    {'truck'}    PointCloud    Cuboid       {'Vehicles'}    {0x0 char}     {1x3 double}    {0x0 double}
    {'sunny'}    Time          Scene        {'None'    }    {0x0 char}     {1x3 double}    {0x0 double}

Inspect the ROI labels. The object contains labels for the lidar point cloud sequence and the video.

gTruth.ROILabelData
ans = 

  ROILabelData with properties:

    video_01_city_c2s_fcw_10s: [204x2 timetable]
                lidarSequence: [34x2 timetable]

Create a new groundTruthMultisignal object that contains only labels that are of type cuboid.

labelTypes = labelType.Cuboid;
gtLabel = selectLabelsByLabelType(gTruth,labelTypes);

For the original and new objects, inspect the first five rows of label data for the lidar point cloud sequence. Because the lidar point cloud signal in the original object contains only cuboid labels, the new object contains the same label data for the lidar sequence as the original object.

lidarLabels = gTruth.ROILabelData.lidarSequence;
lidarLabelsSelection = gtLabel.ROILabelData.lidarSequence;

numrows = 5;
head(lidarLabels,numrows)
head(lidarLabelsSelection,numrows)
ans =

  5x2 timetable

       Time            car            truck    
    ___________    ____________    ____________

    0 sec          {1x1 struct}    {1x0 struct}
    0.29926 sec    {1x1 struct}    {1x0 struct}
    0.59997 sec    {1x1 struct}    {1x0 struct}
    0.8485 sec     {1x1 struct}    {1x0 struct}
    1.1484 sec     {1x1 struct}    {1x0 struct}


ans =

  5x2 timetable

       Time            car            truck    
    ___________    ____________    ____________

    0 sec          {1x1 struct}    {1x0 struct}
    0.29926 sec    {1x1 struct}    {1x0 struct}
    0.59997 sec    {1x1 struct}    {1x0 struct}
    0.8485 sec     {1x1 struct}    {1x0 struct}
    1.1484 sec     {1x1 struct}    {1x0 struct}

For the original and new objects, inspect the first five rows of label data for the video. Because video signals do not support the Cuboid label type, the new object contains no label data for the video.

videoLabels = gTruth.ROILabelData.video_01_city_c2s_fcw_10s;
videoLabelsSelection = gtLabel.ROILabelData.video_01_city_c2s_fcw_10s;

head(videoLabels,numrows)
head(videoLabelsSelection,numrows)
ans =

  5x2 timetable

      Time          car            truck    
    ________    ____________    ____________

    0 sec       {1x3 struct}    {1x0 struct}
    0.05 sec    {1x3 struct}    {1x0 struct}
    0.1 sec     {1x3 struct}    {1x0 struct}
    0.15 sec    {1x3 struct}    {1x0 struct}
    0.2 sec     {1x3 struct}    {1x0 struct}


ans =

  5x0 empty timetable

Input Arguments

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Multisignal ground truth data, specified as a groundTruthMultisignal object or vector of groundTruthMultisignal objects.

Label types, specified as a labelType (Computer Vision Toolbox) enumeration or vector of labelType enumerations.

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

unique(gTruth.LabelDefinitions.LabelType)

Example: labelType.Cuboid

Example: [labelType.Cuboid labelType.Scene]

Output Arguments

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

Each groundTruthMultisignal object in gtLabel corresponds to a groundTruthMultisignal object in the gTruth input. The returned objects contain only the labels that are of the label types specified by the labelTypes input.

Limitations

  • Selecting sublabels by label type is not supported.

Introduced in R2020a