Apple Inc.
Dynamic thresholds for always listening speech trigger

Abstract:

Systems and processes are disclosed for dynamically adjusting a speech trigger threshold, which can be used in triggering a virtual assistant. Audio input can be received via a microphone. The received audio input can be sampled, and a confidence level can be determined of whether the sampled audio input includes a portion of a spoken trigger. In response to the confidence level exceeding a threshold, a virtual assistant can be triggered to receive a user command from the audio input. The threshold can be dynamically adjusted in response to perceived events (e.g., events indicating a user may be more or less likely to initiate speech interactions, events indicating a trigger may be difficult to detect, events indicating a trigger was missed, etc.), thereby minimizing both missed triggers and false positive triggering events.