RobotCar Seasons: Projecting the point cloud into the reference images

[tsattler]

Problem: Using the camera intrinsics stored in the .out and .nvm files or provided in the intrinsics folder together with the provided poses for the overcast-reference images leads to slight shifts in the projected positions.

Reason: The reference poses for the overcast-reference images were created using SfM by refining the poses provided by GPS/INS. As part of the refinement process, we allowed that the intrinsics are also refined.

Fix: In order to get the most accurate projections, you should use the intrinsics provided in the COLMAP reconstructions under 3D-models/invididual/colmap_reconstructions.

[tsattler]

In general, the intrinsics stored in the .out and .nvm are an approximation to the correct intrinsics: Both assume that the principal point is in the center of the image and use only a single focal length value.