Query regarding converting colmap pose to your format

[NagabhushanSN95]

Hi,

From the explanations in README and Issue-10, I understand that the coordinate system of colmap is different from yours. So, you convert the pose matrix estimated by colmap into your coordinate system in https://github.com/Fyusion/LLFF/blob/master/llff/poses/pose_utils.py#L51, right?

But when we change the basis vectors, we need to multiply permutation matrix on both sides of the rotation matrix right?
I mean, a rotation matrix in colmap coordinates

r11 r12 r13
r21 r22 r23
r31 r32 r33

when converted to your coordinates should become

 r22  r21 -r23
 r12  r11 -r13
-r32 -r31 -r33

Instead your code only switches columns to get

r12 r11 -r13
r22 r21 -r23
r32 r31 -r33

Can you please explain why you do not exchange rows of the rotation matrix? (Also, when we change the coordinate systems, even translation vector has to be appropriately modified, right? But your code doesn't modify that either. )