Ultrasonic occupant detection and classification system
First Claim
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1. A method for classifying an occupant in a predetermined volume comprising:
- transmitting an ultrasonic signal having a predetermined transmitter amplitude and a predetermined ultrasonic frequency through the predetermined volume;
receiving a composite ultrasonic signal comprising a signal component produced by interference between the transmitted ultrasonic signal and a returning reflection of the transmitted ultrasonic signal from an occupant within the predetermined volume;
amplitude demodulating the composite ultrasonic signal to isolate the signal component;
analyzing the signal component to derive frequency data therefrom; and
classifying the occupant within the predetermined volume from the derived frequency data of the interference signal component.
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Abstract
An ultrasonic occupant detection and classification system transmits an ultrasonic signal and receives a composite signal containing interference created between the transmitted ultrasonic signal and a reflection of that signal from a moving occupant. A signal component of the received, composite signal is extracted by amplitude demodulation and bandpass filtered to derive a frequency characteristic that is compared to stored frequency data; and the derived and stored data are compared to identify frequencies characteristic of respiration and/or other movements characteristic of living beings.
30 Citations
20 Claims
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1. A method for classifying an occupant in a predetermined volume comprising:
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transmitting an ultrasonic signal having a predetermined transmitter amplitude and a predetermined ultrasonic frequency through the predetermined volume;
receiving a composite ultrasonic signal comprising a signal component produced by interference between the transmitted ultrasonic signal and a returning reflection of the transmitted ultrasonic signal from an occupant within the predetermined volume;
amplitude demodulating the composite ultrasonic signal to isolate the signal component;
analyzing the signal component to derive frequency data therefrom; and
classifying the occupant within the predetermined volume from the derived frequency data of the interference signal component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for classifying an occupant in a predetermined volume comprising:
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means for transmitting an ultrasonic signal having a predetermined transmitter amplitude and a predetermined ultrasonic frequency through the predetermined volume;
means for receiving a composite ultrasonic signal comprising a signal component produced by interference between the transmitted ultrasonic signal and a returning reflection of the transmitted ultrasonic signal from an occupant within the predetermined volume;
means for amplitude demodulating the composite ultrasonic signal to isolate the signal component;
means for analyzing the signal component to derive frequency data therefrom; and
means for classifying the occupant within the predetermined volume responsive to the derived frequency data of the interference signal component. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification