OpenCV version 3.3.1 has an implementation of MSER algorithm, and one possible option is setPass2Only, but it's not specify in the documentation what is it for: https://docs.opencv.org/trunk/d3/d28/classcv_1_1MSER.html#aba564613ffdcd6a89ef0e381c4b02c48 I don't understand exactly how is the implementation of the algorithm, but what I understand from what I see, is that one could use that option to run just the "brighter to darker" part of the algorithm, but if this is like this, how is it if I want to run "darker to brighter" only?
The MSER algorithm consists of 2 steps:
You can see in the OpenCV source code that pass2only parameters allows to execute only one step, namely MSER-.
If you want to execute only the MSER+ step