CompressedImage

Create compressed image message

Since R2019b

Description

The CompressedImage object is an implementation of the sensor_msgs/CompressedImage message type in ROS. The object contains the compressed image and meta-information about the message. You can create blank CompressedImage messages and populate them with data, or subscribe to image messages over the ROS network. To convert the image to a MATLAB^® image, use the readImage function.

Only images that are sent through the ROS Image Transport package are supported for conversion to MATLAB images.

Creation

Syntax

msg = rosmessage('sensor_msgs/CompressedImage')

Description

msg = rosmessage('sensor_msgs/CompressedImage') creates an empty CompressedImage object. To specify image data, use the msg.Data property. You can also get these image messages off the ROS network using rossubscriber.

Properties

MessageType — Message type of ROS message

character vector

This property is read-only.

Message type of ROS message, returned as a character vector.

Data Types: char

Header — ROS Header message

Header object

This property is read-only.

ROS Header message, returned as a Header object. This header message contains the MessageType, sequence (Seq), timestamp (Stamp), and FrameId.

Format — Image format

character vector

Image format, specified as a character vector.

Example: 'bgr8; jpeg compressed bgr8'

Data — Image data

uint8 array

Image data, specified as a uint8 array.

Object Functions

readImage

Convert ROS image data into MATLAB image

Examples

Read and Write CompressedImage Messages

Read and write a sample ROS CompressedImage message by converting it.

Load sample ROS messages and inspect the image message. The imgcomp object is a sample ROS CompressedImage message object.

exampleHelperROSLoadMessages
imgcomp

imgcomp = 
  ROS CompressedImage message with properties:

    MessageType: 'sensor_msgs/CompressedImage'
         Header: [1x1 Header]
         Format: 'bgr8; jpeg compressed bgr8'
           Data: [30376x1 uint8]

  Use showdetails to show the contents of the message

Create a MATLAB image from the CompressedImage message using readImage and display it.

I = readImage(imgcomp);
imshow(I)

Create Blank Compressed Image Message

compImg = rosmessage('sensor_msgs/CompressedImage')

compImg = 
  ROS CompressedImage message with properties:

    MessageType: 'sensor_msgs/CompressedImage'
         Header: [1x1 Header]
         Format: ''
           Data: [0x1 uint8]

  Use showdetails to show the contents of the message

Version History

Introduced in R2019b