vision.labeler.loading.MultiSignalSource Class

Namespace: vision.labeler.loading
Superclasses: matlab.mixin.Heterogeneous

Interface for loading signal data into Ground Truth Labeler app

Description

The vision.labeler.loading.MultiSignalSource class creates an interface for loading signals from a data source into the Ground Truth Labeler app. The data source can be a file format or any custom source.

The interface created using this class enables you to customize the panel for loading custom data sources in the Add/Remove Signal dialog box of the app. The figure shows a sample loading panel.

The class also provides an interface to read frames from loaded signals. The app renders these frames for labeling.

To define a custom class to load a data source into the app, follow these steps.

1. Create a class that inherits from the vision.labeler.loading.MultiSignalSource class. The class definition must have this format, where customSourceClass is the name of your custom data source class.

   classdef customSourceClass < vision.labeler.loading.MultiSignalSource

2. Save the class to this folder, where matlabroot is the full path to your MATLAB^® installation folder as returned by the matlabroot function.

   <matlabroot>\toolbox\vision\vision\+vision\+labeler\+loading

   Alternatively, create a +vision/+labeler/+loading folder structure, add these folders to the MATLAB search path, and save the class to the +vision/+labeler/+loading folder. The Ground Truth Labeler app recognizes data source classes in folders with this path only.

3. Define the class properties and methods required to load the data source into the app. This table shows the predefined custom classes that you can use as starting points for defining these properties and methods.

   Class	Data Source Loaded by Class	Command to View Class Source Code
   vision.labeler.loading.VideoSource	Video file	edit vision.labeler.loading.VideoSource
   vision.labeler.loading.ImageSequenceSource	Image sequence folder	edit vision.labeler.loading.ImageSequenceSource
   vision.labeler.loading.VelodyneLidarSource	Velodyne® packet capture (PCAP) file	edit vision.labeler.loading.VelodyneLidarSource
   vision.labeler.loading.RosbagSource	Rosbag file	edit vision.labeler.loading.RosbagSource
   vision.labeler.loading.PointCloudSequenceSource	Point cloud sequence folder	edit vision.labeler.loading.PointCloudSequenceSource
   vision.labeler.loading.CustomImageSource	Custom image format	edit vision.labeler.loading.CustomImageSource

   For an explanation of the required properties and methods used for defining a custom data source class, see the Create Class for Loading Custom Ground Truth Data Sources example.

The vision.labeler.loading.MultiSignalSource class is a handle class.

Class Attributes

Abstract

true

For information on class attributes, see Class Attributes.

Properties

Name — Name of source type

string scalar

Name of the type of source that this class loads, specified as a string scalar.

Attributes:

GetAccess	public
Abstract	true
Constant	true
NonCopyable	true

Description — Description of class functionality

string scalar

Description of the functionality that this class provides, specified as a string scalar.

Attributes:

GetAccess	public
Abstract	true
Constant	true
NonCopyable	true

SourceName — Name of data source

string scalar

Name of the data source, specified as a string scalar. Typically, SourceName is the name of the file from which the signal is loaded.

Attributes:

GetAccess	public
SetAccess	protected

SourceParams — Parameters for loading signals from data source

structure

Parameters for loading signals from the data source into the app, specified as a structure. The fields of this structure contain values that the loadSource method requires to load the signal.

Attributes:

GetAccess	public
SetAccess	protected

SignalName — Names of signals in data source

string vector

Names of the signals that can be loaded from the data source, specified as a string vector.

Attributes:

GetAccess	public
SetAccess	protected

SignalType — Types of signals in data source

vector of vision.labeler.loading.SignalType enumerations

Types of the signals that can be loaded from the data source, specified as a vector of vision.labeler.loading.SignalType enumerations. Each signal listed in the SignalName property is of the type in the corresponding position of SignalType.

Attributes:

GetAccess	public
SetAccess	protected

Timestamp — Timestamps of signals in data source

cell array of duration vectors

Timestamps of the signals that can be loaded from the data source, specified as a cell array of duration vectors. Each signal listed in the SignalName property has the timestamps in the corresponding position of Timestamp.

Attributes:

GetAccess	public
SetAccess	protected

NumSignals — Number of signals in data source

nonnegative integer

Number of signals that can be read from the data source, specified as a nonnegative integer. NumSignals is equal to the number of signals in the SignalName property.

Attributes:

GetAccess	public
SetAccess	public
Dependent	true
NonCopyable	true

Methods

Public Methods

customizeLoadPanel	customizeLoadPanel(sourceObj,panel) Customize the loading panel for the data source object. In the loading dialog box of the app, this method is invoked when you select the data source type from the Source Type list. Abstract true
getLoadPanelData	[sourceName,sourceParams] = getLoadPanelData(sourceObj) Obtain the data needed to load the data source object currently selected in the loading panel. In the loading dialog box of the app, this method is invoked when you add a source. The method returns these outputs. sourceName is a string capturing the name of the data source object. sourceParams is a structure with fields containing the parameters required to load the data source object. Both of these outputs are passed to the loadSource method. Abstract true
loadSource	loadSource(sourceObj,sourceName,sourceParams) Load a data source object into the app. In the loading dialog box of the app, this method is invoked after you add a source and the getLoadPanelData method executes successfully. This method is also invoked when you load the data source object into the MATLAB workspace. When you load the data source object, MATLAB expects that the source has the name sourceName and parameters sourceParams that are needed to load that source and read data from it. Abstract true
readFrame	frame = readFrame(sourceObj,signalName,tsIndex) Read a frame of data from a signal contained in a data source object at the specified timestamp index. The index must be in the bounds of the length of the timestamps for that signal. Abstract true
loadPanelChecker	loadPanelChecker Check the load panel for the loading dialog box of the app. This method opens a dialog box similar to the loading dialog box that you open from the Open menu on the app toolstrip. Use this method to preview how the customizeLoadPanel method populates the loading panel for the selected data source object. Static true

Version History

Introduced in R2020a