System speakers are switched to function as sound input transducers to improve
recognizer performance and to support recognizer features. A crossbar switch is
selectively activated, either manually or under software control, to allow system
loudspeakers to function as sound input transducers that supplement the recognition
system microphone or microphone array. Using loudspeakers as "microphones" improves
speech recognition in noisy environments, thus attaining better recognition performance
with little added system cost. The loudspeakers, positioned in physically separate
locations also provide spatial information that can be used to determine the location
of the person speaking and thereby offer different functionality for different
persons. Acoustic models are selected based on environmental and vehicle operating
conditions and may be adapted dynamically using ambient information obtained using
the loudspeakers as sound input transducers.
