camera "double vision" leading to error: process has died

[Linusnie]

I want to use ethzasl_ptam to calibrate my USB-camera for lsd SLAM. I've been following this guide but when I start the calibration the image I'm getting in the calibration window is distorted (like it overlaps two images) and after between a couple of seconds and a minute it throws an error. I have changed bluefox_ros_node/image_raw to usb_cam/image_raw in cameracalibrator.launch to match my image topic and ImageSizeX, ImageSizeY in PtamFixParams.yaml to the size of the physical checker pattern (in millimeters), otherwise the code is untouched.

Here are some screen shots of the setup. In the first picture you have my camera output in the lower left window and the camera calibrator in the lower right. The second picture shows the error.

I am using ROS indigo on ubuntu 14.04.3. The camera is a Sandstrøm USB-webcam but I get the same problem if I use in-build camera on my laptop.

Any idea what's going on here? All help is appreciated!

[AmaniEnac]

Hello,

I am having exactly the same problem.
Please let me know if you have found a solution to this problem.

Thank you

[gscortichini]

Hello, i have the same problem.

[Linusnie]

I never ended up solving this (had to move on to other things) will make sure to post if I figure it out though

[stephanweiss]

I would say this is an issue with your camera node for the USB camera. Please make sure that this node publishes a clean 8bit grayscale image under usb_cam/image_raw

[weblucas]

my guess is that you are using a color camera.

use this to convert to greyscale

than use as input to PTAM the topic /image_mono

On 4 February 2016 at 22:03, Stephan Weiss [email protected] wrote:

I would say this is an issue with your camera node for the USB camera.
Please make sure that this node publishes a clean 8bit grayscale image
under usb_cam/image_raw

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[gscortichini]

Yes, i was using a color camera, that was the reason.

PTAM needs monocromatic frames, and usb_cam/image_raw is not good. You have to use another node between usb_cam/image_raw and the PTAM calibration tool.
I used image_proc that create many topics and one of them is the usb_cam/image_mono that is perfect for the calibration! Try it!

[liu-zg15]

I think he is right. @weblucas
You can change your camera's parameter(In my case, mono8 works well for me.).