selectLabelsBySignalName

R2026b

Select multi-sensor ground truth by signal name

Since R2026b

Syntax

gtLabel = selectLabelsBySignalName(gTruth,signalNames)

Description

gtLabel = selectLabelsBySignalName(gTruth,signalNames) selects labels for the signals specified by signalNames from a groundTruthMultiSensor object, gTruth. The function returns a corresponding groundTruthMultiSensor object, gtLabel, that contains only the selected labels. If gTruth is a vector of groundTruthMultiSensor objects, then the function returns a vector of corresponding groundTruthMultiSensor objects that contain only the selected labels. Use this function to isolate label data for specific sensors in a multi-sensor ground truth object.

Examples

Select Ground Truth Labels by Signal Name

Select ground truth labels from a groundTruthMultiSensor object by specifying a signal name.

This example assumes you have a groundTruthMultiSensor object, gTruth, in the workspace containing ROI and scene label data for a video and corresponding lidar point cloud sequence.

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: [204×2 timetable]
                lidarSequence: [34×2 timetable]

Create a new groundTruthMultiSensor object that contains labels for only the lidarSequence signal.

signalNames = "lidarSequence";
gtLabel = selectLabelsBySignalName(gTruth,signalNames);

For the original and new objects, inspect the first five rows of label data for the lidar point cloud sequence. 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)

       Time            car            truck
    ___________    ____________    ____________

    0 sec          {1×1 struct}    {1×0 struct}
    0.29926 sec    {1×1 struct}    {1×0 struct}
    0.59997 sec    {1×1 struct}    {1×0 struct}
    0.8485 sec     {1×1 struct}    {1×0 struct}
    1.1484 sec     {1×1 struct}    {1×0 struct}

       Time            car            truck
    ___________    ____________    ____________

    0 sec          {1×1 struct}    {1×0 struct}
    0.29926 sec    {1×1 struct}    {1×0 struct}
    0.59997 sec    {1×1 struct}    {1×0 struct}
    0.8485 sec     {1×1 struct}    {1×0 struct}
    1.1484 sec     {1×1 struct}    {1×0 struct}

For the original and new objects, inspect the first five rows of label data for the video. 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)

      Time          car            truck
    ________    ____________    ____________

    0 sec       {1×3 struct}    {1×0 struct}
    0.05 sec    {1×3 struct}    {1×0 struct}
    0.1 sec     {1×3 struct}    {1×0 struct}
    0.15 sec    {1×3 struct}    {1×0 struct}
    0.2 sec     {1×3 struct}    {1×0 struct}

      Time
    ________

    0 sec
    0.05 sec
    0.1 sec
    0.15 sec
    0.2 sec

Input Arguments

gTruth — Multi-sensor ground truth data

groundTruthMultiSensor object | vector of groundTruthMultiSensor objects

Multi-sensor ground truth data, specified as a groundTruthMultiSensor object or vector of groundTruthMultiSensor objects.

signalNames — Signal names

character vector | string scalar | cell array of character vectors | string vector

Signal names, specified as a character vector, string scalar, cell array of character vectors, or string vector.

To view all signal names in a groundTruthMultiSensor object, gTruth, enter this command at the MATLAB^® command prompt.

gTruth.DataSource.SignalName

Example: "lidarSequence"

Example: "lidarSequence"

Example: {"lidarSequence","imageSequence"}

Example: ["lidarSequence" "imageSequence"]

Output Arguments

gtLabel — Ground truth with only selected labels

groundTruthMultiSensor object | vector of groundTruthMultiSensor objects

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

Each groundTruthMultiSensor object in gtLabel corresponds to a groundTruthMultiSensor object in the gTruth input. The returned objects contain only the labels with signal names specified by the signalNames input.

Version History

Introduced in R2026b