Recent years have seen development of electronic devices including a speech recognition function. For example, at the beginning of the year 2012, Samsung Electronics Co., Ltd. released a television (TV) which can be operated using speech recognition.
The TV can be operated by speech from a user (hereinafter, may also be referred to as user speech) in the following manner. The user speaks a keyword which instructs, for example, turning the volume up or down, or selecting a channel. When the speech recognition function included in the TV recognizes the keyword, a command associated with the keyword is issued to the TV, thereby operating the TV.
In this case, the keyword may be output by the TV itself by chance. For example, it is assumed that the speech “channel 10” is the keyword instructing the TV channel to be changed to channel 10. When a person appearing on a TV program on the TV speaks “channel 10” by chance, the speech “channel 10” is output from a loudspeaker of the TV. The output speech is collected by a microphone and recognized, resulting in an unintentional change of the TV channel to channel 10.
Patent Literature (PTL) 1 and PTL 2, for example, disclose techniques to prevent a device from incorrectly operating due to the speech output by the device itself.
When a keyword spoken by a user causes a device to issue a command associated with the keyword, the user speech needs to be accurately recognized. PTL 3, for example, discloses such a technique for accurately recognizing the user speech.