MATLAB Answers

Image format error when reading ROS compressed images

50 views (last 30 days)
Hi,
I am trying to read ROS compressed images from Matlab using the following commands. I use a real Turtlebot3 robot.
imgSub = rossubscriber('/raspicam_node/image/compressed');
imgMsg = receive(imgSub);
rgbImg = readImage(imgMsg);
The last line gives this error:
Error using robotics.ros.msg.sensor_msgs.CompressedImage/readImage (line 64)
Could not find a semicolon in format character vector jpg. Modify the "format" property of the message object appropriately.
I found that manually changing the ROS message format solves the problem (change from jpg to bgr8; jpeg compressed bgr8).
imgSub = rossubscriber('/raspicam_node/image/compressed');
imgMsg = receive(imgSub);
imgMsg.Format = 'bgr8; jpeg compressed bgr8';
rgbImg = readImage(imgMsg);
Can someone explain why this happens and if it is possible to solve this without hardcoding the format.
Thanks.

  1 Comment

Francesco Ciriello
Francesco Ciriello on 2 Mar 2020
Have you tried using the '/raspicam_node/image/compressed' and '/raspicam_node/image/' messages in the Simulink readImage block? I can't seem to get anything but error code 1, i.e. Incorrect image encoding. Check that the incoming message encoding matches the ImageEncoding parameter.

Sign in to comment.

Accepted Answer

Cam Salzberger
Cam Salzberger on 13 May 2019
Hello Asanka,
Any messages published by the image_transport package should ensure that the Format field is in the form expected by MATLAB. Consider using the image_transport system on the TurtleBot3, if that is possible.
-Cam

  1 Comment

Sign in to comment.

More Answers (0)

Sign in to answer this question.