Provided is to prevent a false determination due to an attachment condition of an apparatus that transmits and receives an acoustic signal, and perform accurate personal authentication. A personal authentication device includes: a personal authentication means that authenticates an individual by using first information at least including an acoustic characteristic calculated from an acoustic signal propagating through the head of the user, which is detected by an apparatus being attached on a head of a user for transmitting and receiving the acoustic signal, and a feature amount extracted from the acoustic characteristic; an attachment trouble rule storage means that stores an attachment trouble rule for detecting an attachment trouble with the apparatus; and an attachment trouble detection means that detects a trouble with an attachment state of the apparatus when the first information satisfies the attachment trouble rule.

A headrest having a bone conduction two-way sound transmission system is provided. The system has a bone conduction speaker and bone conduction microphone mounted on the same printed circuit board. Additional components of the bone conduction two-way sound transmission system, such as a control unit, contact sensors or proximity sensors, and an antenna for communication with external electronic devices can be mounted on the same printed circuit board. Assembling the components of the system is easy and subsequent assembling the two-way sound transmission system inside the headrest is simpler, faster, and less subject to human errors, thus increasing the quality of the final product while keeping the manufacturing costs low.

A contact sensor for monitoring breathing of a subject, comprising: a microphone housing defining a first acoustic cavity, a MEMS microphone disposed within the first acoustic cavity; a second acoustic cavity separated from the first acoustic cavity by a cavity wall having a front surface and a rear surface, the second acoustic cavity at least partially defined by the front surface of the cavity wall; an acoustic conduit formed between the first acoustic cavity and the second acoustic cavity through the cavity wall; and a pressure relief vent having a first end terminating at the second acoustic cavity and a second end terminating outside of the second acoustic cavity.

A contact sensor for monitoring breathing of a subject, comprising: a microphone housing defining a first acoustic cavity, a MEMS microphone disposed within the first acoustic cavity; a second acoustic cavity separated from the first acoustic cavity by a cavity wall having a front surface and a rear surface, the second acoustic cavity at least partially defined by the front surface of the cavity wall; an acoustic conduit formed between the first acoustic cavity and the second acoustic cavity through the cavity wall; and a pressure relief vent having a first end terminating at the second acoustic cavity and a second end terminating outside of the second acoustic cavity.

A device for detecting sound in the surroundings of an automobile, including a first structure-borne noise sensor, which is acoustically coupled to a first oscillating body at an outside of the automobile and provides a first audio signal, including a second audio signal, which represents sound from an interior of the automobile, and including a processing unit, which is configured to subtract at least the second audio signal from the first audio signal.

A sound collecting apparatus according to an embodiment of the present disclosure includes a sound collecting part that detects sound in a body of an animal, a sound absorbing member that is provided on the sound collecting part, and a contact member that is provided on the sound absorbing member such that the contact member contacts a body surface of the animal, wherein the sound collecting part includes a housing, an opening causing the inside of the housing to be in communication with the outside of the housing on a surface of the housing proximate to the sound absorbing member, and a sound collecting element provided inside the housing for detecting the sound, wherein the sound absorbing member covers the opening of the housing, and protrudes toward the inside of the housing.

One of the main objects of the present invention is to provide a bone conduction microphone with simplified structure and easier manufacturing process. To achieve the above-mentioned objects, the present invention provides a bone conduction microphone, including: a housing; a circuit board opposite to the housing; and a vibration assembly locating between the housing and the circuit board. The vibration assembly includes a vibration membrane made of high temperature resistant dustproof breathable material, a weight fixed to the vibration membrane, and a first cavity formed between the vibration membrane and the circuit board. The bone conduction microphone further includes a pressure assembly locating between the vibration assembly and the circuit board for detecting a pressure change generated in the first cavity and converting the pressure change into an electrical signal.

One of the main objects of the present invention is to provide a bone conduction microphone with simplified structure and easier manufacturing process. To achieve the above-mentioned objects, the present invention provides a bone conduction microphone, including: a housing; a circuit board opposite to the housing; and a vibration assembly locating between the housing and the circuit board. The vibration assembly includes a vibration membrane made of high temperature resistant dustproof breathable material, a weight fixed to the vibration membrane, and a first cavity formed between the vibration membrane and the circuit board. The bone conduction microphone further includes a pressure assembly locating between the vibration assembly and the circuit board for detecting a pressure change generated in the first cavity and converting the pressure change into an electrical signal.

The problem to be solved is to provide a new method and system for appropriately detecting a joint state from an acoustic of a joint. The present method comprises the step of obtaining, using a bio-acoustic sensor, an acoustic signal emitted by a joint during a time period that at least includes a first motion period wherein the joint changes from a first state to a second state, a pause period of the joint and a second motion period wherein the joint changes from the second state to the first state, the step of converting the obtained acoustic signal into time trend data that at least shows a relationship between an acoustic signal intensity and time, and the step of setting, from the time trend data, a basic threshold value regarding the acoustic signal intensity to calculate first acoustic information based on the basic threshold value, characterized in that the first acoustic information is an indicator of the joint state.

The problem to be solved is to provide a new method and system for appropriately detecting a joint state from an acoustic of a joint. The present method comprises the step of obtaining, using a bio-acoustic sensor, an acoustic signal emitted by a joint during a time period that at least includes a first motion period wherein the joint changes from a first state to a second state, a pause period of the joint and a second motion period wherein the joint changes from the second state to the first state, the step of converting the obtained acoustic signal into time trend data that at least shows a relationship between an acoustic signal intensity and time, and the step of setting, from the time trend data, a basic threshold value regarding the acoustic signal intensity to calculate first acoustic information based on the basic threshold value, characterized in that the first acoustic information is an indicator of the joint state.