I'm speaking with no understanding of the processes described, so take this with a grain of salt. ...
Here will be generally understood to mean “at this point” in the process; but the question is just what point is being identified?
I would ordinarily take here to refer to the action of the first sentence: segmenting raw points. This reading would imply that classifying planar segments happens at the same time as segmenting raw points—or is possibly even the same thing as segmenting raw points.
Your parenthesis, however, seems to say that these two steps, segmenting and classifying, are distinct and consecutive. Here may imply that, but it does not necessarily do so; on the contrary, the ‘default’ is the one given in my preceding paragraph.
In writing generally, and highly technical writing in particular, the Adamantine Law is that “Whatever can be misunderstood will be”. Consequently, you must make every effort to avoid any possible ambiguity. You would do better to use some other adverb than here. If you mean that the two steps happen at the same time, say so explicitly:
As each segment is identified it is classified as terrain or non-terrain using an adaptation of a rule-based classification step described by BBB (2007).
If you mean that the two steps are consecutive, then say that explicitly:
When all segments have been identified they are classified &c.
In either case, put what you do—classify—first, then explain how you do it, just as you did in the first sentence. You are describing a process, so keep that in the foreground and background your methodological sources.
(Besides, adapting the BBB classification doesn’t take place here under either reading; it must be presumed that you performed the adaptation some time before you followed the procedure you are describing!)