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2.7 Wavelet denoising

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Wavelets can be used in a wide range of applications, one of which is noise reduction. This module shows a real-time implementation of a wavelet-based noise reduction in the DSK6713. A Simulink model is created for simulation, and afterwards used for DSP code generation.

Introduction

Wavelets can be used in a range of applications, one of which is noise reduction.

This laboratory shows how to design a model of Wavelet Noise Reduction using Simulink and run it on a Texas Instruments C6000 DSP.

Objectives

  • Design a model of Wavelet Noise Reduction for the Texas Instruments C6000 family of DSP devices using MATLAB® and Simulink®.
  • Modify an existing Simulink demonstration model.
  • Run the project on the Texas Instruments C6713 DSK with a microphone and computer loudspeakers / headphones.

Level

Intermediate. Assumes prior knowledge of MATLAB and Simulink. It also requires a theoretical understanding of wavelets and some knowledge of Texas Instruments DSPs.

Hardware and software requirements

This laboratory was originally developed using the following hardware and software:

  • MATLAB R2006b with Embedded Target for TI C6000.
  • Code Composer Studio (CCS) v3.1
  • Texas Instruments C6713 DSK hardware.
  • Microphone and computer loudspeakers / headphones.

Related files

Simulation

Simulink model

The Simulink model described here is based on a MATLAB Demo.

Opening the model

Open WaveletDenoising.mdl

Opening WaveletDenoising.mdl

Running the model

Run the model. The colors change to show the different filter channels. Green = high frequency.

Wavelet Model Showing Color Coding

Scope output

The scope output shows how the random noise has been separated out (Residual).

Scope Output

Monitoring the dyadic filter outputs

Add an extra scope as shown in Figure 4 to display the Diadic Filter Outputs.

Monitoring the Dyadic Filter Outputs

Analysis of diadic filter outputs

It can be seen that the noise is on Out1, Out2 and Out3. The clean input signal is on Out4.

Noise Levels at Dyadic Filter Outputs

Modifying the dead zone

Double-click on the “Soft Threshold” block. This is the actual noise reduction stage. The fields are in order Out1, Out2, Out3 and Out4.

Noise Levels at Dyadic Filter Outputs

Here Out1 has been given a threshold of 3. This means that only values>3 are let through.

Out2, Out3 and Out4 have been given the value of 0. This means the whole signal is let through.

The output is shown in Figure 6. Note that the noise associated with Out2 and Out3 have not been reduced.

Threshold only applied to Out1

Changing the delay alignment

Double-click on the “Delay Alignment” block. Temporarily remove the delays on Out1 and Out2.

Removing the Delay Alignments

Run the model to see the effect.

Summary of simulation

From practical experimentation using the Simulink model, you should now understand how wavelet denoising works.

Real-time model for ti c6713 dsk

Texas instruments c6713 dsk setup

Texas Instruments C6713 DSK Setup

Questions & Answers

Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
Kate Reply
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
Kate Reply
what is the change in momentum of a body?
Eunice Reply
what is a capacitor?
Raymond Reply
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
Maria Reply
please solve
Sharon
8m/s²
Aishat
What is Thermodynamics
Muordit
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
Saheed Reply
50 m/s due south east
Someone
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
Ramon Reply
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
Someone
definitely of physics
Haryormhidey Reply
how many start and codon
Esrael Reply
what is field
Felix Reply
physics, biology and chemistry this is my Field
ALIYU
field is a region of space under the influence of some physical properties
Collete
what is ogarnic chemistry
WISDOM Reply
determine the slope giving that 3y+ 2x-14=0
WISDOM
Another formula for Acceleration
Belty Reply
a=v/t. a=f/m a
IHUMA
innocent
Adah
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
Nassze Reply
how do lnternal energy measures
Esrael
Two bodies attract each other electrically. Do they both have to be charged? Answer the same question if the bodies repel one another.
JALLAH Reply
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you. Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Robert
like charges repel while unlike charges atttact
Raymond
What is specific heat capacity
Destiny Reply
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
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Source:  OpenStax, From matlab and simulink to real-time with ti dsp's. OpenStax CNX. Jun 08, 2009 Download for free at http://cnx.org/content/col10713/1.1
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