Re: RGBD SLAM and then RGB Localization

Posted by matlabbe on
URL: http://official-rtab-map-forum.206.s1.nabble.com/RGBD-SLAM-and-then-RGB-Localization-tp489p502.html

Hello Bernard,

1. It is to remove distortion in the image so camera intrinsic K can be used alone to reproject 3D points to image plane without using distortion coefficients D. In cv::solvePnPRansac(), they are cameraMatrix and distCoeffs parameters. If the image is rectified, you don't need to specify distCoeffs. Maybe your smartphone has already a camera with very low distortion, so you may not specify them or explicitly rectify the image. Otherwise, the rtabmap-calibration gives also the D coefficients.

2. The local transform for SensorData is the transform from a fixed frame on the robot and the frame of the sensor. In ROS, in can be referred as /base_link -> /camera_link. By default in RTAB-Map hand-held mapping, the local transform is the rotation of the sensor from the image referential (x right, y down, z forward) to world referential (x forward, y left, z up). This transform is generally constant.

cheers