Very unclear names, https://github.com/scipy/scipy-cookbook/blob/master/ipython/bundle_adjustment.ipynb i don't understand the variable used in this code at all? for example: **points_2d** with shape (n_observations, 2) contains measured 2-D coordinates of points projected on images in each observations. in what image exactly are the coordinates given, assuming i see the point in multiple images, what coordinate do i enter exactly?