rosWriteIntensity

Write intensity data points to a ROS or ROS 2 PointCloud2 message structure

Since R2023a

Syntax

msgOut = rosWriteIntensity(msgIn,intensity)

msgOut = rosWriteIntensity(msgIn,intensity,Name=Value)

Description

msgOut = rosWriteIntensity(msgIn,intensity) writes the intensity values from m-by-1 matrix or m-by-n matrix of 3-D point to a ROS or ROS 2 sensor_msgs/PointCloud2 message msgIn and stores the data points in the message msgOut.

msgOut = rosWriteIntensity(msgIn,intensity,Name=Value) specifies additional options using one or more name-value arguments.

Examples

Write Intensity Data Points to a ROS or ROS 2 PointCloud2 Message

This example shows how to write intensity data points to a ROS or ROS 2 PointCloud2 message structure. To write intensity data points to a ROS or ROS 2 PointCloud2 message, you must write x,y and z data points first.

Create a random m-by-n-by-3 matrix with x, y and z coordinate points.

xyzPoints = single(10*rand(480,640,3));

Create a sensor_msgs/PointCloud2 message in ROS network.

rosMsg = rosmessage("sensor_msgs/PointCloud2","DataFormat","struct")

rosMsg = struct with fields:
    MessageType: 'sensor_msgs/PointCloud2'
         Header: [1x1 struct]
         Height: 0
          Width: 0
         Fields: [0x1 struct]
    IsBigendian: 0
      PointStep: 0
        RowStep: 0
           Data: [0x1 uint8]
        IsDense: 0

Write the x, y and z coordinate points to the ROS message and set PointStep of sensor_msgs/PointCloud2 to 16 to store the intensity data points.

rosMsg = rosWriteXYZ(rosMsg,xyzPoints,"PointStep",16)

rosMsg = struct with fields:
    MessageType: 'sensor_msgs/PointCloud2'
         Header: [1x1 struct]
         Height: 480
          Width: 640
         Fields: [3x1 struct]
    IsBigendian: 0
      PointStep: 16
        RowStep: 10240
           Data: [4915200x1 uint8]
        IsDense: 1

Create a random m-by-n matrix with intensity values.

intensity = uint8(10*rand(480,640));

Write the intensity information to the ROS message and set the offset of the intensity field in sensor_msgs/PointField to 8. This means that intensity field begins to be stored from 16th byte for each PointStep.

rosMsg = rosWriteIntensity(rosMsg,intensity,"FieldOffset",8)

rosMsg = struct with fields:
    MessageType: 'sensor_msgs/PointCloud2'
         Header: [1x1 struct]
         Height: 480
          Width: 640
         Fields: [4x1 struct]
    IsBigendian: 0
      PointStep: 16
        RowStep: 10240
           Data: [4915200x1 uint8]
        IsDense: 1

You can also create a sensor_msgs/PointCloud2 message in ROS 2 network.

ros2Msg = ros2message("sensor_msgs/PointCloud2");

Write the x, y and z coordinate points to the ROS 2 message. Set PointStep to 16.

ros2Msg = rosWriteXYZ(ros2Msg,xyzPoints,"PointStep",16)

ros2Msg = struct with fields:
     MessageType: 'sensor_msgs/PointCloud2'
          header: [1x1 struct]
          height: 480
           width: 640
          fields: [3x1 struct]
    is_bigendian: 0
      point_step: 16
        row_step: 10240
            data: [4915200x1 uint8]
        is_dense: 1

Write the intensity information to the ROS 2 message and set FieldOffset to 8.

ros2Msg = rosWriteIntensity(ros2Msg,intensity,"FieldOffset",8)

ros2Msg = struct with fields:
     MessageType: 'sensor_msgs/PointCloud2'
          header: [1x1 struct]
          height: 480
           width: 640
          fields: [4x1 struct]
    is_bigendian: 0
      point_step: 16
        row_step: 10240
            data: [4915200x1 uint8]
        is_dense: 1

Input Arguments

msgIn — PointCloud2 message

"struct"

PointCloud2, specified as a structure for ROS or ROS 2 sensor_msgs/PointCloud2 message.

Data Types: struct

intensity — List of intensity values

m-by-1 vector | m-by-n matrix

List of intensity values, specified as a m-by-1 vector or m-by-n matrix.

Data Types: single | double | int32 | uint8 | uint16 | uint32

Name-Value Arguments

Example: PointStep=pointstep

PointStep — Provides optional parameter for setting up the point step value of the input sensor_msgs/PointCloud2 message

uint32(0) (default)

Point step is number of bytes or data entries for one point. If the PointStep field is not set in the input sensor_msgs/PointCloud2 message, you can use this parameter to manually set the PointStep information.

Example: msgOut = rosWriteIntensity(msgIn,intensity,PointStep=pointstep)

Data Types: uint32

FieldOffset — provides optional parameter for setting up the offset of a PointField of the input sensor_msgs/PointCloud2 message

uint32(0) (default)

Field Offset is number of bytes from the start of the point to the byte in which the field begins to be stored. If the offset field is not set for a PointField in the input sensor_msgs/PointCloud2 message, you can use this parameter to manually set the offset information.

Example: msgOut = rosWriteIntensity(msgIn,intensity,FieldOffset=fieldoffset)

Data Types: uint32

Output Arguments

msgOut — PointCloud2 message

"struct"

PointCloud2, specified as a structure for ROS or ROS 2 'sensor_msgs/PointCloud2' message.

Data Types: struct

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• Usage in MATLAB Function block is not supported.

Version History

Introduced in R2023a