1. A method for unattended detection of a current terrain to be traversed by a mobile device, comprising the steps of: receiving, from a visual sensor, visual input of the current terrain for a plurality of positions; receiving audio input corresponding to the current terrain for the plurality of positions; fusing the video input with the audio input using a classifier; and classifying the type of the terrain with the classifier.
11. The method of claim 1 , wherein the audio input is represented by one of a Gaussian mixture model (GMM), a hidden Markov model, and a time-delay neural network (TDNN).