3. The method of claim 2 , wherein the expectation-maximization (EM) method comprises the steps of: constructing a parameterized video processing function based on the visual input received over the plurality of positions; constructing a parameterized audio processing function based on the audio input received over the plurality of positions; holding the video processing function fixed and optimizing the parameterized audio processing function using the EM method to produce an optimized audio classification of the terrain; holding the audio processing function fixed and optimizing the parameterized video processing function using the EM method to produce an optimized video classification of the terrain; and associating the optimized audio classification with the optimized video classification to produce ,an optimized fused classification of the current terrain.
3. The method of claim 2 , wherein the expectation-maximization (EM) method comprises the steps of: constructing a parameterized video processing function based on the visual input received over the plurality of positions; constructing a parameterized audio processing function based on the audio input received over the plurality of positions; holding the video processing function fixed and optimizing the parameterized audio processing function using the EM method to produce an optimized audio classification of the terrain; holding the audio processing function fixed and optimizing the parameterized video processing function using the EM method to produce an optimized video classification of the terrain; and associating the optimized audio classification with the optimized video classification to produce ,an optimized fused classification of the current terrain. 4. The method of claim 3 , wherein parameters of at least one of the video and audio processing function are obtained using a regression.