[ros-users] problems with image_proc using a modified camera

Caroline Pantofaru pantofaru at willowgarage.com
Thu Apr 8 19:57:36 UTC 2010

Or, if you do want to change the scaling post-calibration, you can change
the P matrix in the camera_info by scaling the P(0,0), P(0,3), P(1,1)
entries. You can find the value to scale by with a little trial and error.

On Thu, Apr 8, 2010 at 12:32 PM, James Bowman <jamesb at willowgarage.com>wrote:

> Hi Dave,
> you can actually use the slider in the  cameracalibration app to do this
> border operation for you.  Tutorial:
> http://www.ros.org/wiki/camera_calibration/Tutorials/MonocularCalibration
> I've just added a paragraph (copied from the corresponding
> StereoCalibration tutorial) to make this clearer:
> After a successful calibration, you can use the slider at the top of the
> calibration window to change the size of the rectified image. A scale of 0.0
> means that the image is sized so that all pixels in the rectified image are
> valid. The rectified image has no border, but some pixels from the original
> image are discarded. A scale of 1.0 means that all pixels in the original
> image are visible, but the rectified image has black borders where there are
> no input pixels in the original image.
> On Wed, Apr 7, 2010 at 3:51 PM, David Feil-Seifer <
> david.feilseifer at 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
>> _______________________________________________
>> ros-users mailing list
>> ros-users at code.ros.org
>> https://code.ros.org/mailman/listinfo/ros-users
> --
> J.
> _______________________________________________
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