NOISE REDUCTION IN SPEECH
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
seminar class
Active In SP
**

Posts: 5,361
Joined: Feb 2011
#1
03-03-2011, 09:50 AM


PRESENTED BY:
K.AKILA
N.DEEPTHA
D.NARMADA


.ppt   final ppt.ppt (Size: 1.18 MB / Downloads: 62)
 NOISE REDUCTION IN SPEECH
• Noise is an unwanted disturbance superimposed on a
useful signal, which tends to obscure its information
content.
• The background noise is the most common factor
degrading the quality and intelligibility of speech .
• The noise reduction technique intends to lower the
noise level without affecting the quality of speech signal.
OBJECTIVE
• To achieve intelligibility, naturalness and overall
perceptual quality of the speech signal.
• To improve the signal strength.
 NOISE DATA
 Factory Noise
 HF Channel Noise
 Babble Noise
 White Noise
 Pink Noise
 Car Interior Noise
 Cockpit Noise
 N.S - Noisy Speech
A.C - Approximation Coefficients
D.C - Detail Coefficients
ICA - Independent Component Analysis
ZCR - Zero Crossing Rate
N.R.S - Noise Reduced Speech
 STANDARD DATABASE
SPEECH SIGNAL :
TEXT : SHE HAD YOUR DARK SUIT IN GREASY WASH
WATER ALL YEAR
SAMPLE LENGTH : 63488 samples
SAMPLING FREQUENCY :16000Hz
VARIANCE :E(X2)-(E(X))2
Variance of the SPEECH SIGNAL(in dB) : -74.5232
 ORIGINAL SPEECH SIGNAL
 FREQUENCIES IN THE SPEECH SIGNAL
 FREQUENCIES IN THE NOISE
 NOISY SPEECH SIGNAL
 FREQUENCIES IN THE NOISY SPEECH
 VARIANCE :E(X2)-(E(X))2
Variance of the SPEECH SIGNAL(in dB) : -74.5232
Variance of the NOISE(in dB) : -106.1482
Variance of the NOISY SPEECH(in dB) : -74.1012
FRAMING
NON-OVERLAPPING FRAMES OF 16msec DURATION.
NUMBER OF FRAMES :248
 WAVELET DECOMPOSITION
 WAVELET USED - DAUBECHIES WAVELET db1
DECOMPOSITION LEVEL - LEVEL 2
APPROXIMATION COEFFICIENTS :
Correspond to speech combined with low frequency noise in the frequency band (0-2000Hz).
DETAIL COEFFICIENTS :
Correspond to the contribution due to speech in the frequency band (2000-4000Hz).
 WAVELET RECONSTRUCTION
APPROXIMATION COEFFICIENTS AND DETAIL
COEFFICIENTS are UPSAMPLED.
RECONSTRUCTED SIGNAL
Variance of the RECONSTRUCTED
SIGNAL in(0-2000 Hz) (in dB) : -76.4146
 EXTRACTION OF NOISE FROM NOISY SPEECH
 To analyze the noise frequencies, we need to extract the noise from noisy speech.
 Wavelet transform of LEVEL 2 is used to extract the speech in low frequency band (0-2000 Hz) and to find the starting frame.
 A Modified probability density function is calculated.
 A negative wavelet entropy computed using modified probability density function is used for determining the starting frame.
MODIFIED PROBABILITY DENSITY FUNCTION
i-frame number
j-sample in a frame
Wi(j) –wavelet energy of the jth sample in ith frame
K-positive constant=1.8
NEGATIVE ENTROPY CALCULATION
The negative wavelet entropy is given as

E(i) = Pi(j)*log(Pi(j))

Pi(j) -Modified probability function
 The negative wavelet entropy is more negative for noise and silence frames and less negative for speech frames.
 Starting frame is determined from the entropy comparison
ENTROPY PLOT
DETERMINING THE STARTING FRAME

A THRESHOLD is set
THRESHOLD=(MEAN(entropy)+MEDIAN(entropy))/2
THRESHOLD= -74.32
STARTING FRAME :46
The ending frame is also determined.
END FRAME : 234
BOUNDARY PLOT
CONCLUSION

Variance of the NOISY SPEECH(in dB)= -74.1012
Variance of the RECONSTRUCTED = -76.4146
SIGNAL from wavelet decomposition (in dB)
There is an improvement in the intelligibility of the noisy speech which is proved by hearing the speech at each stage.

Reply

Important Note..!

If you are not satisfied with above reply ,..Please

ASK HERE

So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page

Quick Reply
Message
Type your reply to this message here.


Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)

Possibly Related Threads...
Thread Author Replies Views Last Post
  Reduction of Sidelobes by Non-uniform Elements Spacing pdf study tips 0 229 06-08-2013, 03:13 PM
Last Post: study tips
  Noise Characterization of A/D Converter on PIC Microcontroller PPT study tips 0 316 05-06-2013, 12:28 PM
Last Post: study tips
Thumbs Up continuous speech processing vickysutrave 4 2,973 06-02-2013, 09:56 AM
Last Post: kowsalyamspvl
  Speech Recognition PPT project girl 0 364 14-12-2012, 05:36 PM
Last Post: project girl
  SPEECH CODING: FUNDAMENTALS AND APPLICATIONS pdf project girl 0 336 10-12-2012, 12:07 PM
Last Post: project girl
  Noise Control Ordinance pdf project girl 0 385 22-11-2012, 04:08 PM
Last Post: project girl
  SPEECH RECOGNITION MICROCONTROLLER seminar flower 0 392 09-10-2012, 10:18 AM
Last Post: seminar flower
  NOISE CANCELLATION BY ADAPTIVE FILTERING seminar ideas 1 568 01-10-2012, 11:52 AM
Last Post: seminar tips
  SPEECH, IMAGE, BIOMEDICAL & INFORMATION PROCESSING seminar flower 0 351 27-09-2012, 12:54 PM
Last Post: seminar flower
  A BUS ENCODING TO REDUCE CROSSTALK NOISE EFFECT IN SYSTEM ON CHIP seminar flower 0 365 22-09-2012, 02:27 PM
Last Post: seminar flower