## Image upside down when streaming to ROS

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Rick Shen
Posts: 4
Joined: 15 Oct 2018, 01:30

### Image upside down when streaming to ROS

Hi, I am using ROSInterface to streaming VisionSensor data to ROS. However, when I run the demo scene rosInterfaceTopicPublisherAndSubscriber.ttt from VREP official ROS tutorial, the image published to ros is upside down.

I never change any code from the template. The passive vision sensor is having a normal display. But the image_view and Rviz all shows upside down.

Why is this happen? How to solve this problem?

BTW, I saw a previous discussion to add a "flip image vertically" filter. But that will also flip the display in the VREP, which influence the simulation effect.

The problem is similar in this ROS answer but I don't quite understand what they mean.

coppelia
Posts: 7838
Joined: 14 Dec 2012, 00:25

### Re: Image upside down when streaming to ROS

Hello,

you can flip the retrieved image buffer with following:

Code: Select all

    local data,w,h=sim.getVisionSensorCharImage(activeVisionSensor)
sim.transformImage(data,{w,h},4)

Cheers