why jacob of depth is set to ones?

princeton-vl / DROID-SLAM

BSD 3-Clause "New" or "Revised" License

1.66k stars 273 forks source link

why jacob of depth is set to ones? #30

Closed sconlyshootery closed 2 years ago

sconlyshootery commented 2 years ago

Thanks for your excellent work! I have a little confusion about the calculation of jacob of depth below: https://github.com/princeton-vl/DROID-SLAM/blob/92027b31c06f42e4471706bbb46e7eb3cb3a5dd0/droid_slam/geom/projective_ops.py#L34 why the jacob is set to ones, I think it might be a function of intrinsics and image coordinates. Please help me figure it out, thank you very much in advance!

sconlyshootery commented 2 years ago

According to my understanding, the 3D coordinates are set to: X=[(u-cx)/fx, (v-cy)/fy, 1, disp] so differential with respect to disp is: [0,0,0,1] However, you seem to set it to [1,1,1,1].