US 4,538,295 A · Speech recognition system for an automotive vehicle

Abstract

A speech recognition system for an automotive vehicle can effectively eliminate noise generated by vehicle engines, and comprises a group of bandpass filters the pass bands of which are approximately from 500 to 600, from 900 to 1200, and from 900 to 2200 Hz, for effectively passing only the speech sound formant frequencies while eliminating the major frequency components of engine noise less than 500 Hz, in addition to the conventional speech recognizer. Further, it is desirable to provide the speech recognition system with a high-frequency compensator for enhancing the voltage level of the high frequency components of the electrical signal representing spoken instructions at a rate of 20 dB or more per decade increase in frequency and/or a plurality of notch filters fo sharply reducing the major engine noise frequency components at 200, 400, and 800 Hz.

Claims12

Dependent claims

A speech recognition system for an automotive vehicle for activating vehicle actuators in response to a spoken instruction signal received through a microphone, comprising:

(a) a voice input section including notch filter means for attenuating frequency components of the signals received through the microphone at approximately 400 Hz;
(b) voice detection means connected to said notch filter means for detecting beginning and end of spoken instruction signals and outputting instruction start and end signals for identifying, respectively, start and end of an instruction;
(c) a plurality of bandpass filter means connected to said notch filter means for further filtering signals filtered through said notch filter means to human speech frequency components and to noise frequency components due to noise resulting from engine operation;
and (d) voice analysis means connected to said bandpass filter means and responsive to the instruction start and end signals for analyzing the signals filtered through said bandpass filter means, comparing analyzed results with predetermined reference values corresponding to at least one spoken instruction, and for activating at least one actuator when the analyzed results match predetermined reference values associated with the actuator.

1 more element

In a speech recognition system for automotive vehicle for activating vehicle actuators in response to spoken instructions received through a microphone, having

(a) a sound input section for filtering signals from a microphone,
(b) a voice detection section connected to said sound input section for detecting the beginning and end of spoken instructions and for outputting instruction start and end signals for identifying, respectively, start and end of an instruction, and
(c) a voice analysis section connected to said input section and responsive to said instruction start and end signals, the improvement comprising:
compensating means in said sound input section for compensating for variable frequency characteristic noise signals present in said signals from a microphone, said compensating means including filter means comprised of first means having a frequency response characterized by a high frequency characteristic substantially inverse to a high frequency characteristic of said noise signals for cancelling said noise signals and for providing a substantially flat response at said high frequencies to said noise signals.

1 more element

Dependencies are inferred from the claim text.

Speech recognition system for an automotive vehicle

Life of this patent

Speech recognition system for an automotive vehicle

Life of this patent

Abstract

Claims12