getPointCloud

Get point cloud image from TurtleBot camera

Syntax

pcloud = getPointCloud(tbot)
[pcloud,pcloudMsg] = getPointCloud(tbot)
[___] = getPointCloud(tbot,timeout)

Description

example

pcloud = getPointCloud(tbot) waits for the next published point cloud message from the TurtleBot® connected through the interface object, tbot, and returns the point cloud image. If no message is received in five seconds, the function displays an error.

[pcloud,pcloudMsg] = getPointCloud(tbot) also returns the received ROS point cloud message.

[___] = getPointCloud(tbot,timeout) waits for the next point cloud image for timeout seconds. If no new message is received in that time, the function displays an error. A timeout of zero returns the latest received message without waiting. If no message has been received, the function returns an empty matrix for pcloud and an empty message for pcloudMsg, if specified.

Examples

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Connect to the TurtleBot robot. Change '192.168.1.1' to the IP address of the robot.

tbot = turtlebot('192.168.1.1');

Get the latest point cloud image from the TurtleBot.

pcloud = getPointCloud(tbot);

Connect to the TurtleBot robot. Change '192.168.1.1' to the IP address of the robot.

tbot = turtlebot('192.168.1.1');

Get the latest point cloud image and message from the TurtleBot.

[pcloud,pcloudMsg] = getPointCloud(tbot);

Get RGB values for each point in the point cloud message using readRGB. You can read other information as MATLAB® data types including readXYZ and readAllFieldNames.

rgb = readRGB(pcloudMsg);

Connect to the TurtleBot robot. Change '192.168.1.1' to the IP address of the robot.

tbot = turtlebot('192.168.1.1');

Get the latest point cloud image and message from the TurtleBot.

[pcloud,pcloudMsg] = getPointCloud(tbot);

Plot the point cloud using scatter3.

scatter3(pcloudMsg)

Input Arguments

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TurtleBot interface object, specified as a turtlebot object. The object contains properties for activating subscribers and accessing topic names relevant to the TurtleBot. The properties contain the topic name and active status of different subscribers for the TurtleBot. When you create the object with turtlebot, the properties available are:

tbot = turtlebot
tbot = 

  turtlebot with properties:

           Velocity: [1x1 struct]
         ColorImage: [1x1 struct]
          GrayImage: [1x1 struct]
         DepthImage: [1x1 struct]
         PointCloud: [1x1 struct]
          LaserScan: [1x1 struct]
           Odometry: [1x1 struct]
      OdometryReset: [1x1 struct]
                IMU: [1x1 struct]
    TransformFrames: {0x1 cell}
         TopicNames: {3x1 cell}

For properties with relevant ROS data messages , you can view the topic name and a subscriber’s active status. A specific subscriber is active for the given TopicName if Active equals 1.

tbot.Velocity
ans = 

    TopicName: '/mobile_base/commands/velocity'
       Active: 1

Timeout for receiving an image, specified as a scalar in seconds. The function returns an error after timeout seconds. If timeout equals zero, the function returns the latest image. If the TurtleBot has no latest message, the function returns a blank image and blank image message.

Output Arguments

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Point cloud image, returned as a structure containing these fields:

  • XYZ — An n-by-3 matrix containing the xyz-coordinates of all n points. Each row represents one 3–D point.

  • RGB — An n-by-3 matrix containing the RGB values of all n points. Each row corresponds to the one 3-D point in pcloud.XYZ.

'sensor_msgs/PointCloud2' ROS point cloud message, returned as a PointCloud2 object handle.

Introduced in R2016a