How to realize image processing with ROS and opencv

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In the other question it sounded like there were callback for user input as well as callbacks from the image message that were confusing the OP http://answers.ros.org/question/63595/ros-iamge-to-opencv-image-and-image-processing/?answer=63774#post-id-63774

Didn't see that bit. I can reopen the other question, if you think it's suitably distinct.

I think it's essentially the same question, just a little detail came out in the comments.

Thank you for your answer! In my program, I don't want to deal image processing each time receive a image and the image process for each frame maybe 100ms. So when I try the webcam, I grab the image when I want to use, now I am trying to do that with ROS… Thank you!

I am going to be crazy and so worry about my program. Compared with my program of webcam, there only difference in getting the image data. In order to say clearly, let me make an example. I try to draw several boxes in the window of image.

When I deal with webcam, I can draw several boxes in the window and name them: "0", "1", "2"...When I deal with ROS, I cam only draw the box "0" and suddenly it will disappear, then I draw again, it will show box "0" again and disapper again.It seems it will refresh. The problem it's like this way.

Hello Anthony, you can choose the rate at which the camera messages are published. You can also choose when you update the images that you're merging (I assume that you're using something like http://dasl.mem.drexel.edu/~noahKuntz/openCVTut2.html#Step%202)

I have tried several ways with it all the day, and I will try to set the loop_rate as you said! Moreover, if you'd like, you could see my code(http://www.zlzdesign.com/pet_drone.cpp) and help me to find the problem! Anyway, you really do me a favor! I will make effect to make it not refresh!