The present teachings provide an autonomous mobile robot that includes a drive configured to maneuver the robot over a ground surface within an operating environment; a camera mounted on the robot having a field of view including the floor adjacent the mobile robot in the drive direction of the mobile robot; a frame buffer that stores image frames obtained by the camera while the mobile robot is driving; and a memory device configured to store a learned data set of a plurality of descriptors corresponding to pixel patches in image frames corresponding to portions of the operating environment and determined by mobile robot sensor events.