Calibration questions

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Calibration questions

Alex
Hello, I have a question regarding the RTAB-Map's calibration feature. I tried to calibrate my Kinect v2 using the printed Sample8x6 chessboard by choosing the Openni2 driver but I can seem to be able to finish the process.
I have reached 280 images and the X and Y values are stuck at around 80%, size is around 40% and skew is at 99%, I assume that when everything reaches to 100% the export yaml button will be clickable so everything needs to be 100% right?
I have calibrated cameras before (regular ones not kinect ones) and I know the different positions you should put the board in order to achieve a successful calibration but no matter how I move the board I don't have any significant progress after the first 100 images.
I was wondering if I am doing something wrong and if you have any tips for the calibration process.
Also I was wondering if there any example yaml files so I could edit and add values from other people who have calibrated a kinect v2?
Is the RGB camera's low resolution (512x424) the reason I cannot finish the calibration? Will changing the RGB camera resolution to a higher value for the calibration and then changing it back to 512x424 for the mapping work? Will the calibration values be the same no matter the resolution?
Shouldn't the depth camera need calibration too? If so how?
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Re: Calibration questions

matlabbe
Administrator
Do you mean Freenect2 driver instead of Openni2? If you are using Openni2 with Kinect v2, I didn't know it works :P. Are you on Windows? Well, there are some issues about the calibration workflow in the main GUI (I opened an issue). It should be used for stereo only (like Bumblebee2), the Kinect/Xtion/Kinectv2 are already calibrated. The drivers Freenect, Openni and Openni2 ignore calibration files and use the factory calibration saved in the camera. If Openni2 works with Kinect v2, I will check how to choose between your own calibration vs factory one like for Freenect2 driver.

With the Freenect2 driver, you can still do a calibration for the Kinect v2 using the rtabmap-calibration tool:
$ rtabmap-calibration --driver 5 --stereo
This will open the calibration dialog with two views, one for RGB images (1920x1080) and one for the IR images (512x424). The progress bars don't need to be 100% to activate the export button, 40% minimum for size and 50% minimum for other parameters. Save the calibration files in a "camera_info" folder in the working directory (default "~/Documents/RTAB-Map").


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Re: Calibration questions

Alex
Thank you for your response, well Openni2 doesn't officially support kinect v2. I used a kinect2 branch in the occipital OpenNI2 repository from this link:
I am using windows, I had to build Rtab-Map and PCL in visual studio 2012 to make it work (which meant I had to comment every piece of code which used openni which doesn't work in VS2012). It is an unorthodox way to use Openni2 and kinect v2 to be honest.
I thought that all drivers were using the calibration files if they existed i.e. you could calibrate an old kinect with Openni2 and use the resulting yaml file. So since technically Openni2 doesn't work with kinect v2 by default there is no reason for you to spend time with the issue. I guess the factory calibration will work for me.

Thank you for your response
Alex