What does each column mean which in poses.txt file

[hnsywangxin]

What does each column mean which in poses.txt file

[hnsywangxin]

I guess these 12 columns constitute the transformation matrix(3x4) which is from camera to velodyne. The first column corresponds to the index (0,0), and the last column corresponds to the index (2,3).
Is this the case?
Thank you !

[jbehley]

Hello @hnsywangxin,

the format corresponds to the same format as the KITTI Odometry format (see also the devkit of the KITTI Odometry Benchmark for further details) , i.e., it's the 3x4 part of a 4x4 homogeneous transformation. The order is (0,0) (0,1) (0,2) (0,3) (1,0) (1,1) ...

Note that in the original KITTI all poses are given in the reference frame of a camera and therefore one has to transform the poses. (therefore the calib.txt is needed)

If you directly want to use the pose of the sensor you can simply set all poses to identity in your calib.txt.

[jbehley]

PS: Something like this here:

point_labeler/scripts/kitti_raw2odometry.py

Lines 159 to 165 in 769c060

	calib_file = open(os.path.join(output_folder, "calib.txt"), "w")
	calib_file.write("P0: 1 0 0 0 0 1 0 0 0 0 1 0\n")
	calib_file.write("P1: 1 0 0 0 0 1 0 0 0 0 1 0\n")
	calib_file.write("P2: 1 0 0 0 0 1 0 0 0 0 1 0\n")
	calib_file.write("P3: 1 0 0 0 0 1 0 0 0 0 1 0\n")
	calib_file.write("Tr: 1 0 0 0 0 1 0 0 0 0 1 0\n")
	calib_file.close()

[hnsywangxin]

Thank you for your help, I will study the code carefully