readIMU

Read IMU data from Ouster PCAP file

Since R2024b

Syntax

imuData = readIMU(ousterReader)

[imuData,tform] = readIMU(ousterReader)

Description

imuData = readIMU(ousterReader) reads all the inertial measurement unit (IMU) data from the Ouster^® PCAP file, and returns a structure that contains accelerometer and gyroscope measurements.

example

[imuData,tform] = readIMU(ousterReader) additionally returns the transformation matrix from the IMU coordinate frame to the lidar coordinate frame.

Examples

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Read IMU Data from Ouster PCAP File

Open Live Script

Download a ZIP file containing an Ouster packet capture (PCAP) file and the corresponding calibration file, and then unzip the file.

zipFile = matlab.internal.examples.downloadSupportFile("lidar","data/ouster_RoadIntersection.zip");
saveFolder = fileparts(zipFile);
pcapFileName = [saveFolder,filesep,'ouster_RoadIntersection',filesep,'ouster_RoadIntersection.pcap'];
calibFileName = [saveFolder,filesep,'ouster_RoadIntersection',filesep,'OS1-128U.json'];
if ~(exist(pcapFileName,"file") && exist(calibFileName,"file"))
    unzip(zipFile,saveFolder);
end

Create an ousterFileReader object using the PCAP and calibration files, and read the IMU data.

ousterReader = ousterFileReader(pcapFileName,calibFileName);
imuData = readIMU(ousterReader);

Display the first three accelerometer readings.

imuData.AccelerometerReadings(1:3,:)

ans=3×1 timetable
       Time                Acceleration          
    __________    _______________________________

    576.64 sec    0.21555     0.58917      9.7837
    576.65 sec    0.22992    -0.40955      9.8387
    576.66 sec    0.23471    -0.16286       9.719

Display the first three gyroscope readings.

gyroReadings = imuData.GyroscopeReadings(1:3,:)

gyroReadings=3×1 timetable
       Time                  AngluarVelocity            
    __________    ______________________________________

    576.64 sec    -0.0099869      0.033689     -0.012117
    576.65 sec    -0.0082558      0.025167    -0.0066579
    576.66 sec    -0.0049268      0.025167     -0.010919

Input Arguments

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`ousterReader` — Ouster file reader
`ousterFileReader` object

Ouster file reader, specified as ousterFileReader object.

Output Arguments

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`imuData` — IMU data
structure

IMU data, returned as a structure with these fields:

Field	Description
`AccelerometerReadings`	Raw accelerometer readings, returned as an M-by-1 `timetable`. M is the number of measurements. The first column of the table specifies timestamps, and the rest of the columns specify raw accelerometer readings along the x-, y-, and z-axes. Units are in m/s².
`GyroscopeReadings`	Raw gyroscope readings, returned as an M-by-1 `timetable`. M is the number of measurements. The first column of the table specifies timestamps, and the rest of the columns specify angular velocities along the x-, y-, and z-axes. Units are in rad/s.