[ros-users] camera_info message and stereo_image_proc

[Dejan Pangercic]

Rosen,

saw this tutorial:
http://www.ros.org/wiki/image_geometry/Tutorials/ProjectTfFrameToImage?
D.

On Tue, Apr 13, 2010 at 6:40 PM, Rosen Diankov <rosen.diankov at gmail.com> wrote:
> So it looks like everyone uses the CameraInfo.P to go from 3D to 2D
> rectified image. I know that CameraInfo has been designed very
> carefully and evolved over the past 2 years, I don't understand why
> the message has both K and P, when P holds the exact same information
> and only it is supposed to be used...
>
> Also, if P describes the 2D/3D relationship for the rectified plane,
> and the camera's TF frame is in the original non-rectified plane, what
> frame should nodes publish their image measurements in to guarantee
> the correct transformations happen?
>
> thanks,
> rosen,
>
> 2010/4/14 Rosen Diankov <rosen.diankov at gmail.com>:
>> Hi Blaise, Dejan,
>>
>> thank you for the responses.
>>
>> We have several ros nodes that compute the 6D pose of objects from
>> images. This data can come from stereo cameras, or can compute from
>> single cameras. Either way, the CameraInfo message explains how the
>> image was generated and it provides an intrinsic matrix, so we try to
>> be consistent and do all processing depending on what the CameraInfo
>> dictates.
>>
>> I don't understand how nodes can just use rectified images without
>> knowing the intrinsic parameters... is there a tf frame that does the
>> intrinsic parameter computation?
>>
>> rosen,
>>
>> 2010/4/14 Blaise Gassend <blaise at willowgarage.com>:
>>> Hi Rosen,
>>>
>>> I believe that the intent is that only image_proc and stereo_image_proc
>>> are supposed to look at CameraInfo.D. All other nodes should be running
>>> on rectified images and should disregard the distortion parameters.
>>>
>>> Do you have a use case of a node that needs to be able to run both on
>>> rectified and unrectified images and, that needs to use the distortion
>>> parameters?
>>>
>>> Blaise
>>>
>>> On Tue, 2010-04-13 at 17:42 +0900, Rosen Diankov wrote:
>>>> hi guys,
>>>>
>>>> currently i'm using the videre_stereo_cam package by Antons to get
>>>> stereo data. This publishes the image_raw and camera_info messages as
>>>> expected, which is then fed into stereo_image_proc.
>>>>
>>>> stereo_image_proc itself publishes image_rect, image_color,
>>>> image_mono, which I'm guessing undistort the raw images. However, a
>>>> new camera_info isn't published that has CameraInfo.D set to all
>>>> zeros. This confuses other nodes taking in the processed images and
>>>> the camera_info, so is it possible to publish a new camera_info
>>>> message to use for the output images?
>>>>
>>>> rosen,
>>>> _______________________________________________
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>>>
>>>
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>>
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-- 
MSc. Dejan Pangercic
PhD Student/Researcher
Computer Science IX
Technische Universität München
Telephone: +49 (89) 289-17780
E-Mail: dejan.pangercic at in.tum.de
WWW: http://ias.cs.tum.edu/people/pangercic