getDepthImage

Get depth image from TurtleBot camera

Description

example

depthImg = getDepthImage(tbot) waits for the next published depth image message from the TurtleBot® connected through the interface object,tbot, and returns the image. If no message is received in five seconds, the function displays an error. Depth images measure the distance to an object for each area in the camera field of view.

[depthImg,depthImgMsg] = getColorImage(tbot) also returns the received ROS depth image message.

[___] = getColorImage(tbot,timeout) waits for the next 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 depthImg and an empty message for depthImgMsg, 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 depth image from the TurtleBot.

depthImg = getDepthImage(tbot);

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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Depth image, returned as an m-by-n-by-1 array. Values in the array correspond to distances from the camera sensor to the object in meters. NaN values indicate that no object was detected.

'sensor_msgs/Image' ROS image message, specified as an Image object handle.

Introduced in R2016a