lidar.labeler.loading.LasFileSequenceSource class

Package: lidar.labeler.loading
Superclasses: vision.labeler.loading.MultiSignalSource

Load signals from LAS or LAZ file sequence sources into Lidar Labeler app

Description

The lidar.labeler.loading.LasFileSequenceSource class creates an interface for loading a signal from a LAS or LAZ file sequence data source into the Lidar Labeler app. In the Select Point Cloud dialog box of the app, when Source Type is set to LAS/LAZ File Sequence, this class controls the parameters in that dialog box.

To access this dialog box, in the app, select Import > Add Point Cloud.

The lidar.labeler.loading.LasFileSequenceSource class is a handle class.

Creation

When you export labels from a Lidar Labeler app session that contains a LAS or LAZ file sequence source, the exported groundTruthLidar object stores an instance of this class in its DataSource property.

To create a LasFileSequenceSource object programmatically, such as when programmatically creating a groundTruthLidar object, use the lidar.labeler.loading.LasFileSequenceSource function (described here).

Syntax

lasSeqSource = lidar.labeler.loading.LasFileSequenceSource

Description

lasSeqSource = lidar.labeler.loading.LasFileSequenceSource creates a LasFileSequenceSource object for loading a signal from a LAS or LAZ file sequence data source. To specify the data source and the parameters required to load the source, use the loadSource method.

Properties

Name — Name of source type

"LAS/LAZ File Sequence" (default) | string scalar

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

Attributes:

GetAccess	public
Constant	true
NonCopyable	true

Description — Description of class functionality

"A LAS/LAZ file sequence reader" (default) | string scalar

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

Attributes:

GetAccess	public
Constant	true
NonCopyable	true

SourceName — Name of data source

[] (default) | 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 LAS or LAZ file sequence signal from data source

[] (default) | structure

Parameters for loading a LAS or LAZ file sequence signal from a data source, specified as a structure.

This table describes the required and optional fields of the SourceParams structure.

Field	Description	Required or Optional
Timestamps	Timestamps for the LAS or LAZ file sequence signal, specified as a cell array containing a single duration vector of timestamps. In the Select Point Cloud dialog box of the app, if you set the Timestamps parameter to From Workspace and read the timestamps from a variable in the MATLAB® workspace, then the SourceParams property stores these timestamps in the Timestamps field.	Optional If you set the Timestamps parameter to Use Default and use the default timestamps for LAS or LAZ file sequence signals, then the structure does not include this field, and the SourceParams property is empty, []. For LAS or LAZ file sequence signals, the default timestamp duration vector has elements from 0 to the number of valid LAS or LAZ files minus 1. Units are in seconds.

Attributes:

GetAccess	public
SetAccess	protected

SignalName — Names of signals in data source

[] (default) | 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

[] (default) | 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

[] (default) | 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

0 (default) | 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.
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.
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.
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.
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

Examples

Create LAS File Sequence Source

Specify the path to a folder containing a LAS file sequence.

lasSeqFolder = fullfile(toolboxdir('lidar'),'lidardata','las');

The LAS file consists of two point cloud frames that occur at one-second intervals. Specify the timestamps of the frames as a duration vector of two seconds.

timestamps = seconds(1:2);

Create a LAS file sequence source. Load the folder path and timestamps into the LasFileSequenceSource object.

sourceName = lasSeqFolder;
sourceParams = struct;
sourceParams.Timestamps = timestamps;

lasSeqSource = lidar.labeler.loading.LasFileSequenceSource;
loadSource(lasSeqSource,sourceName,sourceParams)

Read the second frame in the sequence. Display the frame.

signalName = lasSeqSource.SignalName;
pc = readFrame(lasSeqSource,signalName,2);

figure
pcshow(pc)

Version History

Introduced in R2020b