TECHNICAL FIELD

This relates to the detection of speech, and in particular to detecting when a speaker is a person who is using a device, for example wearing a wearable accessory such as an earphone.

BACKGROUND OF THE INVENTION

Wearable accessories, such as earphones, smart glasses and smart watches, are common. There are situations in which it is desirable to know whether the person speaking, when speech is detected, was the person wearing a particular accessory. For example, when an accessory is being used in connection with a device such as a smartphone that has speech recognition functionality, it is useful to know whether detected speech was spoken by the person wearing the accessory. In that case, speech that was spoken by the person wearing the accessory can be supplied to the speech recognition functionality so that any spoken commands can be acted upon, while speech that was not spoken by the person wearing the accessory can be ignored in some circumstances.

SUMMARY OF THE INVENTION

According to the embodiments described herein, there is provided a method and a system which reduce or avoid one or more of the disadvantages mentioned above.

According to a first aspect of the invention, there is provided a method of own voice detection for a user of a device, the method comprising:detecting a first signal representing air-conducted speech using a first microphone of the device;detecting a second signal representing bone-conducted speech using a bone-conduction sensor of the device;filtering the first signal to obtain a component of the first signal at a speech articulation rate;filtering the second signal to obtain a component of the second signal at the speech articulation rate;comparing the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate; anddetermining that the speech has not been generated by the user of the device, if a difference between the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate exceeds a threshold value.

According to a second aspect of the invention, there is provided a system, for own voice detection for a user of a device, the system comprising:an input for receiving a first signal representing air-conducted speech from a first microphone of the device and a second signal representing bone-conducted speech from a bone-conduction sensor of the device;at least one filter for filtering the first signal to obtain a component of the first signal at a speech articulation rate and for filtering the second signal to obtain a component of the second signal at the speech articulation rate;a comparator for comparing the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate; anda processor for determining that the speech has not been generated by the user of the device, if a difference between the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate exceeds a threshold value.

According to a third aspect of the invention, there is provided a method of detecting a spoof attack on a speaker recognition system, the method comprising:detecting a first signal representing air-conducted speech using a first microphone of a device;detecting a second signal representing bone-conducted speech using a bone-conduction sensor of the device;filtering the first signal to obtain a component of the first signal at a speech articulation rate;filtering the second signal to obtain a component of the second signal at the speech articulation rate;comparing the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate;determining that the speech has not been generated by a user of the device, if a difference between the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate exceeds a threshold value; andperforming speaker recognition on the first signal representing speech, if the difference between the component of the first signal at the articulation rate and the component of the second signal at the articulation rate does not exceed the threshold value.

The method may further comprise:determining whether the device is being worn or held, andperforming at least the step of comparing the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate only if it is determined that the device is being worn or held.

The method may further comprise:performing voice keyword detection on the first signal representing speech; andperforming speaker recognition on the first signal representing speech only if a predetermined voice keyword is detected in the first signal representing speech.

The method may further comprise:if the result of performing speaker recognition is a determination that the speech was generated by an enrolled user, performing speech recognition on the first signal representing speech.

The device may be a wearable device, in which case the user of the device is a wearer of the device. The wearable device may be an earphone, smart glasses, or a smart watch.

Alternatively, the device may be a handheld device. The handheld device may be a mobile phone.

According to a fourth aspect of the invention, there is provided a speaker recognition system, comprising:an input for receiving a first signal representing air-conducted speech from a first microphone of a device and a second signal representing bone-conducted speech from a bone-conduction sensor of the device;at least one filter for filtering the first signal to obtain a component of the first signal at a speech articulation rate, and for filtering the second signal to obtain a component of the second signal at the speech articulation rate;a comparator, for comparing the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate;a processor for determining that the speech has not been generated by a user of the device, if a difference between the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate exceeds a threshold value; anda speaker recognition block, for performing speaker recognition on the first signal representing speech, if the difference between the component of the first signal at the articulation rate and the component of the second signal at the articulation rate does not exceed the threshold value.

The system may further comprise:a detection circuit for determining whether the device is being worn or held,wherein the system is configured for performing at least the step of comparing the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate only if it is determined that the device is being worn or held.

The system may further comprise:a voice keyword detection block, for receiving the first signal representing speech,wherein the system is configured for performing speaker recognition on the first signal representing speech only if a predetermined voice keyword is detected in the first signal representing speech.

The system may be configured for performing speech recognition on the first signal representing speech, if the result of performing speaker recognition is a determination that the speech was generated by an enrolled user.

The device may be a wearable device, and the user of the device may be a wearer of the device. The wearable device may be an earphone, smart glasses, or a smart watch.

The device may be a handheld device. The handheld device may be a mobile phone.

