David,

It doesn't look like you are doing anything special to sync the
timestamps in letterbox/image_raw and letterbox/camera_info. If they
are out of sync, image_proc may not work properly. I've seen a mention
of a special CameraPublisher class that can help you to do that (see
http://www.ros.org/doc/api/image_transport/html/classimage__transport_1_1CameraPublisher.html).
You should also take a look at
http://www.ros.org/doc/api/image_transport/html/classimage__transport_1_1CameraSubscriber.html
, as it might simplify gathering both the image_raw and camera_info
topics.

- Eric

On Wed, Apr 7, 2010 at 6:51 PM, David Feil-Seifer
<david.feilseifer@gmail.com> wrote:
> I am trying to use image_proc to rectify an image which is just a
> camera image that has a border added around. The purpose is to make a
> rectified image that includes all of the image (including what does
> not strictly fit into a square), not just the centermost part. To do
> this I made a new node image_letterboxer (included source) to add the
> border and to adjust the camera calibration cx and cy params to
> reflect the new center of the image. This has worked when not using
> image_proc to do the undistort.
>
> However, when I try to use this node with image_proc, it does not work
> at all. I dug a little into the source and found that the image
> transport is subscribing to the new image topics correctly, and that
> image transport is registering that subscription, but no callbacks are
> being called. My image_letterboxer node works well enough so that
> image_view can display the new image_raw topic with the letterboxed
> image, but image_proc does not work, though it does work on the camera
> itself.
>
> I assume that the problem is in the image_letterboxer node, but I
> cannot figure out what I did wrong. Is there some flaw in the way that
> I'm using image_transport to publish the images? Or is there something
> wrong with image_proc?
>
> Thanks in advance,
> -Dave
>
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