[Robotics] Camera calibration parameters

[Gilberto Echeverria]

Thanks for the suggestions. It would indeed be strange to calibrate the 
camera in the simulation. We expected to avoid this step inside Blender, 
since the data required should be already defined and exist somewhere in 
Blender. The focal length seems to be a modifiable property of the 
camera object in Blender, but the image size is still evading us.
For the moment we'll try to estimate this measurement from the pattern 
image.

Thanks.
Gilberto


On 05/11/2010 03:28 PM, Paul Fitzpatrick wrote:
> Another (somewhat strange, but fun) method would be to run a standard
> calibration program (e.g. from OpenCV).  You'd need to make a plane with
> a pattern like this on it:
>     http://www.vision.caltech.edu/bouguetj/calib_doc/htmls/pattern.pdf
> Then light it, animate it moving around, record several views from the
> camera, and run the calibration program.
>
> Cheers,
> Paul
>
> On 05/11/2010 06:41 AM, koen buys wrote:
>    
>> Hi Gilberto,
>>
>> I once figured this out in a previous version of blender. Together
>> with Herve Legrand. I will forward you our experiments back then.
>> You need both the intrinsic and the external calibration matrix. The
>> external should be fairly easy to find. The internal one was more
>> difficult.
>> I hope they didn't change the API of that part.
>>
>> Best regards,
>>
>> Koen Buys
>>
>>
>> On 11 May 2010 11:14, Gilberto Echeverria<gilberto.echeverria at laas.fr
>> <mailto:gilberto.echeverria at laas.fr>>  wrote:
>>
>>      Hello everyone,
>>
>>      As part of the Open Robots Simulator (now called MORSE), we are now
>>      connecting Blender with other robotics software modules that do the
>>      processing of the data sent by the simulation. In the case of
>>      image data
>>      from a camera, these modules expect the image to have an associated
>>      calibration matrix.
>>
>>      The calibration matrix is composed with the focal point, the focal
>>      length and the dimensions of the acquired image as a number of pixels
>>      per unit of distance. For the simulated camera in Blender, we can
>>      consider the focal point to be (0,0). For the other two parameters we
>>      have been unable to find the data in Blender. We are using the Blender
>>      camera object and the VideoTexture module to generate captured images.
>>      Does anyone know where this information could be found in Blender?
>>
>>      Best regards
>>
>>      Gilberto
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