Mellin-transform information extractor for vibration sources

• US 6,675,140 B1
• Filed: 01/28/2000
• Issued: 01/06/2004
• Est. Priority Date: 01/28/1999
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group), UK Research and Innovation
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Patterson, Roy D., Irino, Toshio
• Primary Examiner(s): MCFADDEN, SUSAN IRIS
• Application Number:
  US09/493,661
• Time in Patent Office: 1,439 Days
• Field of Search: 704/203, 704/206, 704/211, 704/216, 704/219, 381/320, 382/100, 382/190
• US Class Current: 704/203
• CPC Class Codes: G06F 17/14 Fourier, Walsh or analogous domain transformations , e.g. Laplace, Hilbert, Karhunen-Loeve, transforms for correlation function computation G06F17/156; spectrum analysers G01R23/16

Abstract

The signal processing method includes the steps of: wavelet-transforming an input signal in a computer; and extracting features of the signal by Mellin-transforming the output of the wavelet transform step in synchrony with the input signal in a computer.

Claims

1. A machine-implemented method of signal processing, comprising the steps of:

receiving an input signal representing a source of vibration;

wavelet-transformingthe input signal; and

extracting features of said input signal by performing a Mellin transform on the output of said wavelet-transforming step in synchrony with periodicity or pseudo-periodicity of said input signal.

2. The machine-implemented method of signal processing according to claim 1, wherein said feature extraction step includes the steps of:

transforming an expression corresponding to a running spectrum obtained by said wavelet transform step to a time-interval/logarithmic-frequencyrepresentation by stabilizing in time in synchrony with the input signal while maintaining the precise structure of the response waveform; and

performing a process corresponding to the Mellin transform on said time-interval/logarithmic-frequencyrepresentation, along an ordinate or abscissa where the value of a product or ratio of the time interval and the frequency is constant.

3. The machine-implemented method of signal processing according to claim 2, further comprising the step of applying an output of the frequency analysis of a signal converted to a computer processable format taking into consideration auditory features, to said step of the Mellin transform.

4. The machine-implementedmethod of signal processing according to claim 1, further comprising the step of applying the output of a frequency analysis of a signal converted to a computer processable format taking into consideration auditory features, to said step of the Mellin transform.

5. The machine-implemented method of signal processing according to claim 1, wherein said features represent properties of the input signal relating to the source of vibration.

6. The machine-implemented method of signal processing according to claim 1, wherein the input signal corresponds at least in part to a voice of a person.

7. The machine-implementedmethod of signal processing according to claim 1, wherein the steps of wavelet-transforming and extracting features are each performed using a computer.

8. A signal processing apparatus comprising:

wavelet transform means for wavelet-transforming an input signal representing a source of vibration which has been converted to a computer processable predetermined format; and

feature extraction means for extracting signal features by Mellin-transforming the output of said wavelet transform in synchrony with said input signal.

9. The signal processing apparatus according to claim 8, wherein

said feature extracting means includes

means for transforming a representation corresponding to a running spectrum obtained by said wavelet transform means to a time-interval/logarithmic-frequency representation by stabilizing in time in synchrony with the input signal, while maintaining the precise structure of a the waveform, and

means for performing a process corresponding to the Mellin transform on said time-interval/logarithmic-frequencyrepresentation along a line on which a value of a product or a ratio between time interval and frequency is constant.

10. The signal processing apparatus according to claim 9, further comprising means for applying an output of the frequency analysis of the signal which has been converted to computer processable format taking into consideration auditory features, to said Mellin transform.

11. The signal processing apparatus according to claim 8, further comprising means for applying an output of the frequency analysis of the signal which has been converted to computer processable format taking into consideration auditory features, to said Mellin transform.

12. A signal processing apparatus, comprising:

means for obtaining, in a stabilized time-interval/logarithmic-frequency representation with the origin specified by an input signal representing a source of vibration which has been converted to a computer processable format, a logarithmic time-interval/logarithmic-frequencyrepresentation with the time interval axis being subjected to logarithmic transformation; and

means for transforming said logarithmic time-interval/logarithmic-frequency representation to a new representation having the product of time interval and frequency as the abscissa and logarithmic frequency as the ordinate, and for performing integral transformation on the representation along the ordinate or the abscissa to extract features of the vibration.

13. The signal processing apparatus according to claim 12, further comprising means for representing a representation space obtained by said integral transform as a time sequence of a representation vector at a certain time point.

14. The signal processing apparatus according to claim 13, further comprising means for applying the output of a frequency analysis of the signal which has been converted to computer processable format taking into consideration auditory features, to said Mellin transform.

15. A machine-implementedmethod of signal processing, comprising the steps of:

receiving an input signal representing a source of vibration;

obtaining, in a stabilized time-interval/logarithmic-frequencyrepresentation with the origin specified by periodicity or pseudo-periodicity of the input signal, a logarithmic time-interval/logarithmic-frequencyrepresentation with time interval axis being subjected to logarithmic transform; and

converting said logarithmic time-interval/logarithmic-frequencyrepresentation to a new representation having the product of time interval and frequency as the abscissa and logarithmic frequency as the ordinate, and performing an integral transform on the representation along the ordinate or abscissa to extract features of the vibration.

16. The machine-implemented method of signal processing according to claim 15, further comprising the step of representing a representation space obtained by said integral transform as a time sequence of a representation vector of a certain time point.

17. The machine-implementedmethod of signal processing according to claim 16, further comprising the step of applying the output of a frequency analysis of a signal converted to a computer processable format taking into consideration auditory features, to said step of the Mellin transform.

18. The machine-implementedmethod of signal processing according to claim 15, wherein the input signal corresponds at least in part to a voice of a person.

19. The machine-implemented method of signal processing according to claim 15, wherein the features represent properties of the input signal relating to the source of vibration.

20. The machine-implementedmethod of signal processing according to claim 15, wherein the steps of obtaining and converting are each performed using a computer.