Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Noise suppression device

A noise suppression and noise technology, which is applied in the field of noise suppression devices, can solve the problems of voice degradation, voice recognition rate reduction, etc., and achieve the effect of less sound distortion

Inactive Publication Date: 2014-09-24
MITSUBISHI ELECTRIC CORP
View PDF6 Cites 3 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Devices that implement these functions are often used in high-noise environments, so background noise is also input into the microphone together with the voice, resulting in deterioration of the voice of the call and a decrease in the voice recognition rate, etc.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Noise suppression device
  • Noise suppression device
  • Noise suppression device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0031] figure 1 It is a block diagram showing the overall configuration of the noise suppressing device according to the first embodiment. The noise suppression device according to Embodiment 1 includes an input terminal 1, a Fourier transform unit 2, a power spectrum calculation unit 3, a sound / noise interval determination unit 4, a noise spectrum estimation unit 5, an S / N ratio calculation unit 6, and a probability density function control unit 7 , a suppression amount calculation unit 8 , a spectrum suppression unit 9 , an inverse Fourier transform unit 10 , and an output terminal 11 .

[0032] Hereinafter, the operating principle of the noise suppression device will be described with reference to the drawings.

[0033] First, after A / D (analog / digital) conversion is performed on voice, music, etc. taken in through a microphone (not shown), etc., sampling is performed at a predetermined sampling frequency (for example, 8kHz), and (eg, 10 ms) is divided and input to the no...

Embodiment approach 2

[0094] In Embodiment 1 described above, the probability density function corresponding to the pattern of the input signal was controlled by using the a posteriori SN ratio, but it is also possible to weight the a posteriori SN ratio, for example. The purpose of this is to weight the frequency bands in which there is a high probability of the presence of sound so that the posterior SN ratio becomes higher even though the SN ratio is low despite the presence of sound, such as when the sound signal is drowned by noise. Correction to prevent false suppression of acoustic signals buried by noise.

[0095] Figure 4 is a block diagram showing the overall configuration of the noise suppressing device according to Embodiment 2, Figure 5 It is a block diagram showing the internal structure of the probability density function control part 7a among them. Figure 4 The shown probability density function control unit 7a inputs the power spectrum Y(λ, k) of the power spectrum calculation...

Embodiment approach 3

[0133] In the formula (18) of the above-mentioned Embodiment 3, the weighted value (weighting constant w p (k), w z (k)) is set to be constant in the frequency direction, but may be set to a different value for each frequency. In the weight coefficient calculation section 74, for example, as a general characteristic of sound, the harmonic structure in the low frequency band is clearer (the difference between the peak and the bottom of the spectrum is large), so the weight can be increased and decreased as the frequency becomes higher. Little weighting.

[0134] According to the third embodiment, the weight coefficient calculation unit 74 is configured to control the weighting strength of the weighted-SN ratio calculation unit 75 for each frequency, so that weighting suitable for the frequency characteristics of the sound can be performed, and higher-quality noise suppression can be performed.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

A probability density function control unit (7) obtains a probability density function in accordance with whether an input signal appears to be sound or appears to be noise, that is, a probability density function that is tailored to the distribution of a sound signal in a sound interval and a noise interval. A suppression amount calculation unit (8) uses the probability density function to calculate a spectrum suppression amount.

Description

technical field [0001] The present invention relates to a noise suppression device for suppressing background noise superimposed on an input signal. Background technique [0002] With the development of digital signal processing technology in recent years, outdoor voice calls using mobile phones, hands-free voice calls in automobiles, and hands-free operations based on voice recognition have spread widely. Devices that implement these functions are often used in high-noise environments, so background noise is also input into the microphone along with the voice, resulting in deterioration of call voice and reduction in voice recognition rate. Therefore, in order to realize comfortable voice communication and high-precision voice recognition, a noise suppression device that suppresses background noise mixed into an input signal is required. [0003] As a conventional noise suppression device, for example, there is a method of converting an input signal in the time domain into...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G10L21/0208
CPCG10L21/0208G10L25/84
Inventor 古田训
Owner MITSUBISHI ELECTRIC CORP
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com