readData

Read lane boundary data from lane data object

Since R2023a

Syntax

data = readData(lanedata,"all")

data = readData(lanedata,Timestamps=timestamps)

data = readData(lanedata,RowIndices=rowIndices)

data = readData(___,SortLanes=sortLanes)

Description

Add-On Required: This feature requires the Scenario Builder for Automated Driving Toolbox add-on.

data = readData(lanedata,"all") reads all data from the laneData object lanedata, and returns a table, data.

data = readData(lanedata,Timestamps=timestamps) reads data from the laneData object for the timestamps timestamps you specify.

data = readData(lanedata,RowIndices=rowIndices) reads data from the laneData object for the row indices rowIndices you specify.

data = readData(___,SortLanes=sortLanes) specifies whether to sort the lanes in the output table data.

Examples

Read Data from Lane Data Object Using Row Indices

Load recorded lane boundary data into the workspace.

data = load("laneBoundaryData.mat");

Extract the recorded timestamps and the lane boundaries from the data.

t = data.timestamps;    % Extract timestamps
lbdata = data.lbdata;   % Extract lane boundaries

Initialize a laneData object by using the extracted data.

ld = laneData(t,lbdata);

Specify row indices for which to read data from the laneData object.

idxs = 1:10;

Read data for the specified row indices.

tab = readData(ld,RowIndices=idxs);

Display the table containing the first 10 rows of lane information.

disp(tab)

    TimeStamp           LaneBoundary1                  LaneBoundary2       
    _________    ___________________________    ___________________________

           0     {1×1 parabolicLaneBoundary}    {1×1 parabolicLaneBoundary}
    0.049887     {1×1 parabolicLaneBoundary}    {1×1 parabolicLaneBoundary}
    0.099382     {1×1 parabolicLaneBoundary}    {1×1 parabolicLaneBoundary}
     0.15034     {1×1 parabolicLaneBoundary}    {1×1 parabolicLaneBoundary}
     0.19999     {1×1 parabolicLaneBoundary}    {1×1 parabolicLaneBoundary}
     0.24967     {1×1 parabolicLaneBoundary}    {1×1 parabolicLaneBoundary}
     0.30038     {1×1 parabolicLaneBoundary}    {1×1 parabolicLaneBoundary}
     0.35012     {1×1 parabolicLaneBoundary}    {1×1 parabolicLaneBoundary}
     0.40052     {1×1 parabolicLaneBoundary}    {1×1 parabolicLaneBoundary}
     0.44945     {1×1 parabolicLaneBoundary}    {1×1 parabolicLaneBoundary}

Input Arguments

lanedata — Recorded lane data

laneData object

Recorded lane data, specified as a laneData object.

rowIndices — Row indices for which to read lane information

N-element vector

Row indices for which to read lane information, specified as an N-element vector of positive integers. N is the number of rows of the lanedata input from which to read. Values must be in the range [1, NumSamples], where NumSamples is the value of the NumSamples property of the input laneData object lanedata.

Data Types: single | double | uint8 | uint16 | uint32 | uint64

timestamps — Timestamps for which to read lane information

scalar | N-element vector

Timestamps for which to read lane information, specified as a scalar or an N-element vector. N is the number of timestamps for which to read data from the input lanedata. Units are in seconds. The data in the output table retains the order you specify to this argument.

Data Types: single | double

sortLanes — Sort lanes flag

true or 1 (default) | false or 0

Sort lanes flag, specified as a logical 1 (true) or 0 (false). Specify 1 to sort the lane boundaries in the output table data. Otherwise, specify 0. If you specify 1, the function sorts the lane boundaries in left-to-right order, with respect to the travel direction of the ego vehicle.

Output Arguments

data — Lane detection data

M-by-P table

Lane detection data, returned as an M-by-P table. M is the number of lane-detection samples.

• The first column of the table is the recorded timestamp, in seconds, for each detection in the corresponding row.

• If the input laneData object does not contain LaneInformation and TrackIDs properties, then, all other columns contain data for the detected lane boundaries as parabolicLaneBoundary objects, cubicLaneBoundary objects, or clothoidLaneBoundary objects. All lane boundaries in the table are of the same object type.

• If the input laneData object contains additional lane information LaneInformation, the readData function appends additional columns as a structure specifying additional lane information for each timestamp.

• If the input laneData object contains track IDs of the lane boundary detections TrackIDs, the readData function appends an additional column TrackIDs to the output table which specifies the track IDs of lane boundaries detected at each timestamp.

• If the input laneData object contains both the additional lane information LaneInformation, and the track IDs of the lane boundary detections TrackIDs, then, (P/2–1) is the greatest number of detected lane boundaries across all samples.

This table shows an example of the data organization.

TimeStamp	LaneBoundary1	LaneBoundary2	LaneBoundary1_Info	LaneBoundary2_Info	TrackIDs
0	1x1 parabolicLaneBoundary	1x1 parabolicLaneBoundary	1x1 struct	1x1 struct	1x2 string
0.05	1x1 parabolicLaneBoundary	1x1 parabolicLaneBoundary	1x1 struct	1x1 struct	1x2 string
0.1	1x1 parabolicLaneBoundary	1x1 parabolicLaneBoundary	1x1 struct	1x1 struct	1x2 string

• Empty cells represent missing lane boundary detections.

• The detected lane boundaries are in left-to-right order with respect to the travel direction of the ego vehicle.

• If you specify values in the timestamps argument that do not correspond to timestamps present in the laneData object, the function returns NaN for every column in the corresponding row of the output table data.

Data Types: table

Version History

Introduced in R2023a

R2023a_plus: Additional input argument sortLanes

You can now use an additional input argument, sortLanes, to specify whether to sort the lanes in the output table data.