# Stereo camera calibrator gui does not display measured dimensions after calibration

Hello,

I am trying to use two USB webcams as stereo camera. I am using raspberry pi 3 B with ubuntu mate (16.04) and ros kinetic . I am using uvc_camera package's StereoNodelet. I can see the /image_raw and /Camera_info topics from both the cameras in rostopic list.

Then I ran the stereo camera calibration node as mentioned in the tutorial.

The gui opens and I was able to log images for calibration. After the images were logged and the calibrate button was active, I could complete the calibration and save the calibration data

However when the calibration is complete we can see the epipolar error (epi.) and the measured dimension of the checker box (dim) on the sidebar

But I can only see the epipolar error (epi) on my gui screen and not the measured dimensions.

I am not able to find why this is happening and how to correct it?

in my case, the calibration tool is just showing an ? as the epipolar error. I am also using two individual Logitech usb cameras, but haven't used uvc_camera at all, just stereo_image_proc.