Accident sound detection circuit

• US 5,990,801 A
• Filed: 06/24/1998
• Issued: 11/23/1999
• Est. Priority Date: 11/13/1996
• Status: Expired due to Fees

• Current Assignee: Mitsubshi Electric Engineering Company Limited (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubshi Electric Engineering Company Limited (Mitsubishi Electric Corporation)
• Inventors: Kyouno, Noboru, Seri, Toshimitsu, Koura, Makoto
• Primary Examiner(s): Hopsass, Jeffery A.
• Assistant Examiner(s): PHAM, TOAN NGOC
• Application Number:
  US09/103,311
• Time in Patent Office: 517 Days
• Field of Search: 340/901, 340/902, 340/905, 340/909, 340/910, 340/915, 340/916, 340/917, 340/919, 340/933, 340/943, 340/691.1, 340/691.2, 340/436
• US Class Current: 340/691.1
• CPC Class Codes: G01H 3/06 by electric means
• CPC Class Codes: G01H 3/08 Analysing frequencies present in complex vibrations, e.g. comparing harmonics present acoustic presence detection G01V1/001
• CPC Class Codes: G06V 20/54 of traffic, e.g. cars on the road, trains or boats

Abstract

An accident sound detection circuit includes an accident sound detection block that detects an accident sound from a sound signal inputted from an environmental sound detection unit and outputs an accident sound detection signal, a power spectrum calculator for obtaining a power spectrum in regard to a sound signal when acquiring the accident sound detection signal, outputted from the accident sound detection block, as a trigger signal, a spectrum pattern calculator for forming a pattern of the power spectrum, and a pattern comparator circuit for comparing the formed spectrum pattern and a set pattern set in a pattern generating circuit beforehand and generating a final accident sound detection signal if the patterns coincide with each other.

Claims

1. An accident sound detection circuit for detecting an accident sound by using a sound signal produced by an environmental sound detection unit located in the vicinity of a road, the accident sound detection circuit comprising:

an analog-to-digital (A/D) converter for converting a sound signal from an environmental sound detection unit into a digital sound signal;

differential calculation means for generating an acquired differential signal from an output signal of said A/D converter;

a reference differential value generating circuit for generating a reference differential value;

a comparator circuit for comparing the acquired differential signal to the reference differential value, detecting an accident sound from a comparison of the acquired differential signal to the reference differential value, and generating an accident sound detection signal in response to detecting an accident sound;

power spectrum calculation means for producing a power spectrum of the digital sound signal received from said A/D converter when an accident sound detection signal is generated;

spectrum pattern calculation means for calculating a pattern of the power spectrum and generating a generated spectrum pattern;

a pattern generating circuit for generating an established spectrum pattern of a sound signal for discriminating among different kinds of accident sounds; and

a pattern comparator circuit for comparing the established spectrum pattern to the generated spectrum pattern and generating a final accident sound detection signal when the generated and established spectrum patterns coincide.

2. The accident sound detection circuit according to claim 1, comprising smoothing means for smoothing the digital signal from said A/D converter, wherein said differential calculation means generates the acquired differential signal from an output signal of said smoothing means.

3. The accident sound detection circuit according to claim 1, wherein the spectrum pattern calculation means comprises:

frequency domain separation means for separating frequency components of a power spectrum into a plurality of subbands;

mean value calculation means for obtaining a mean value of the frequency components in each subband;

normalization means for normalizing a level of each mean value for uniformly comparing each mean value to various accident sounds; and

patterning calculation means for patterning normalized mean values.

4. An accident sound detection circuit for detecting an accident sound by using a sound signal produced by an environmental sound detection unit located in the vicinity of a road, the accident sound detection circuit comprising:

an analog-to-digital (A/D) converter for converting a sound signal from an environmental sound detection unit into a digital sound signal;

differential calculation means for generating an acquired differential signal from an output signal of said A/D converter;

a reference differential value generating circuit for generating a reference differential value;

a comparator circuit for comparing the acquired differential signal to the reference differential value, detecting an accident sound from a comparison of the acquired differential signal to the reference differential value, and generating an accident sound detection signal in response to detecting an accident sound;

power spectrum calculation means for producing a power spectrum of the digital sound signal received from said A/D converter when an accident sound detection signal is generated;

spectrum pattern calculation means for calculating a pattern of the power spectrum and generating a generated spectrum pattern;

auto-correlation calculation means for auto-correlation of the digital sound signal;

auto-correlation pattern calculation means for calculating a generated auto-correlation pattern of the auto-correlation of the digital sound signal;

a pattern generating circuit for generating an established spectrum pattern of a sound signal and an established auto-correlation pattern for discriminating among different kinds of accident sounds; and

a pattern comparator circuit for comparing each of the established spectrum pattern and the established auto-correlation pattern to each of the generated spectrum pattern and the generated auto-correlation pattern and generating a final accident sound detection signal when the generated and established spectrum patterns and the generated and established auto-correlation patterns coincide.

5. An accident sound detection circuit for detecting an accident sound by using a sound signal produced by an environmental sound detection unit located in the vicinity of a road, the accident sound detection circuit comprising:

an analog-to-digital (A/D) converter for converting a sound signal from an environmental sound detection unit into a digital sound signal;

differential calculation means for generating an acquired differential signal from an output signal of said A/D converter;

a reference differential value generating circuit for generating a reference differential value;

a comparator circuit for comparing the acquired differential signal to the reference differential value, detecting an accident sound from a comparison of the acquired differential signal to the reference differential value, and generating an accident sound detection signal in response to detecting an accident sound;

power spectrum calculation means for producing a power spectrum of the digital sound signal received from said A/D converter when an accident sound detection signal is generated;

spectrum pattern calculation means for calculating a pattern of the power spectrum and generating a generated spectrum pattern;

signal duration calculation means for calculating signal duration of the digital sound signal;

signal duration pattern calculation means for generating a pattern of the signal duration;

a pattern generating circuit for generating an established spectrum pattern of a sound signal and an established pattern of signal duration for discriminating among different kinds of accident sounds; and

a pattern comparator circuit for comparing each of the established spectrum pattern and the established pattern of signal duration to each of the generated spectrum pattern and the generated time duration pattern and generating a final accident sound detection signal when the generated and established spectrum patterns and the generated and established patterns of signal duration coincide.

6. An accident sound detection circuit for detecting an accident sound by using a sound signal produced by an environmental sound detection unit located in the vicinity of a road, the accident sound detection circuit comprising:

an analog-to-digital (A/D) converter for converting a sound signal from an environmental sound detection unit into a digital sound signal;

differential calculation means for generating an acquired differential signal from an output signal of said A/D converter;

a reference differential value generating circuit for generating a reference differential value;

a comparator circuit for comparing the acquired differential signal to the reference differential value, detecting an accident sound from a comparison of the acquired differential signal to the reference differential value, and generating an accident sound detection signal in response to detecting an accident sound;

power spectrum calculation means for producing a power spectrum of the digital sound signal received from said A/D converter when an accident sound detection signal is generated;

spectrum pattern calculation means for calculating a pattern of the power spectrum and forming a generated spectrum pattern;

auto-correlation calculation means for auto-correlation of the digital sound signal;

auto-correlation pattern calculation means for calculating a generated auto-correlation pattern of the digital sound signal;

signal duration calculation means for calculating signal duration of the digital sound signal;

signal duration pattern calculation means for generating a pattern of the signal duration;

a pattern generating circuit for generating an established spectrum pattern, an established auto-correlation pattern, and an established pattern of signal duration for discriminating among different kinds of accident sounds; and

a pattern comparator circuit comparing each of the established spectrum pattern, the established auto-correlation pattern, and the established pattern of signal duration to each of the generated spectrum pattern, the generated auto-correlation pattern, and the generated pattern of signal duration and generating a final accident sound detection signal when the generated and established spectrum patterns, the generated and established auto-correlation patterns, and the generated and established patterns of signal duration coincide.