lidar_camera_calibration Calibration result is not good

Hi all, I am trying to calibrate a VLP-16 and monocular camera (equipped with a lens with distortion). I followed the steps in the wiki, but the result seems not reasonable. The following picture shows my sensor configuration: _20180524160503

and the result is: plot The position of lidar points looks right. I checked the distance of the closest two points in the center area.

result

By far I haven't figure out the reason for this bad calibration result.

I am wondering if this is caused by the camera intrinsic matrix. I am using a monocular camera with distortion, and I got the K(intrinsic) and D(distortion) by Kalibr, and undistort the images by openCV function. IN the aruco_mapping config file, I filled in the K and D as required, and feed it with mono/image_raw(distorted). But in lidar_camera_calibration, only K is specified. So I use getOptimalCameraMatrix in openCV to get a new_K (I think this new_K is the intrinsic for undistorted camera image), and feed the new_K and mono/image_rect to the lidar_camera_calibration. Is this correct?

Any help will be appreciated. The config files I am using are attached.

Thanks in advance, Zheng

vi_0003.txt config_file.txt lidar_camera_calibration.txt marker_coordinates.txt data bag file: https://drive.google.com/open?id=1MQ9GarLO00LBQpODbdgiaedcEEZmeyzp

Jan 07 '19 07:01 zheng-rong

Emmm... I got the wrong marker size in the config file. After revising that, the calibration result looks good, from the visualization of lidar points overlaid on the image. The RMSE is 0.0327. But compared with manually measured translation, the estimated translation has a large error. In my configuration, the manual measurement is: [-0.013,-0.072,-0.12] and the estimated result is: [-0.0230762,0.0149305,-0.185994]

What may be the reason for this result? Thanks.

Jan 08 '19 08:01 zheng-rong

Can you send your modified configuration file?