1. A method for training a classifier of a mobile robot, the method comprising: obtaining a plurality of image frames along a drive direction of the mobile robot, the plurality of image frames comprising a base image frame corresponding to an initial pose of the mobile robot and subsequent image frames obtained at intervals during forward travel of the mobile robot, the mobile robot having a forward facing camera mounted thereon for obtaining the image frames, the camera having a field of view including a floor in front of the mobile robot, and the mobile robot having a memory device configured to store a learned data set of a plurality of descriptors determined by mobile robot events; assuming that a location is traversable floor, wherein the mobile robot is configured to detect traversable floor and non-traversable non-floor with one or more sensors mounted on the mobile robot; determining that the location is non-traversable non-floor based on a robot sensor event at the location, the robot sensor event comprising detection of a collision; retrieving from a frame buffer an image frame obtained immediately prior to the robot sensor event; generating a floor descriptor corresponding to characteristics of the floor at a bottom of the image frame captured by the camera immediately prior to the robot sensor event; generating a non-floor descriptor corresponding to characteristics of the non-traversable non-floor at a top of the image frame captured by the camera immediately prior to the robot sensor event; and storing the floor descriptor and the non-floor descriptor in the learned data set.