Abstract

Building spoken dialogue systems for space applications requires systems which are flexible, portable to new applications, robust to noise and able to discriminate between speech intended for the system and conversations with other astronauts and systems. Our systems are built to be flexible by using general typed unification grammars for the language models which can be specialized using example data. These are designed so that most sensible ways of expressing a request are correctly recognized semantically. The language models are tuned with extensive user feedback and data if available. The International Space Station and the EVA Suits are noisy (76 and 70 dB SPL ). This noise is best minimized by using active noise canceling microphones which permit accurate speech recognition. Finally open microphone speech recognition is important to hands free, always available operation. Out of domain utterance rejection in its most simple form depends on careful adjustment of rejection thresholds for both acoustic and natural language scores so that out of domain rejection is near 97 and the false rejection rate is around 5 . This means that astronauts can talk to each other and by radio to the ground without the system falsely recognizing a command or query. The effect of statistical and linguistically motivated language modeling techniques will be discussed and shown to be of comparable performance. A short clip of the surface suit spoken dialogue system being used in a field test will be shown.