Ros use Multithreading to publish same message continuously
The situation is I have one camera and I want to extract a depth map of a certain object, which cannot clearly be displayed in the original camera topic. So, I decided to extract the depth map using one camera.
My idea is that first subscribing the /camera/image/rgb_raw topic, then capture one image and store it in a CV object then publish it to a topic called /eye_imitation/left_eye.
After that, move the camera a little bit, then capture another image and publish it to eye_imitation/right_eye topic.
Then, I can subscribe both topics to extract a depth map.
BUT the problem is, is it necessary to use mutithreading to implement this idea, since I have to continuously publish the same image captured before moving the camera and then publishing the image after moving. If I have to use multithreading, can you give me some example about this? I have read the ros wiki page about multi threading but do not have too much idea about the implementation.
Thanks Very much For your help.