BIOMEDICAL SIGNAL PROCESSING (BMSP) TOOLS

Transcription

1 BIOMEDICAL SIGNAL PROCESSING (BMSP) TOOLS A Guide that will help you to perform various BMSP functions, for a course in Digital Signal Processing. Pre requisite: Basic knowledge of BMSP tools : Introduction to LabVIEW programming language NOTE-Before performing the experiment, ensure that you have installed the BMSP installer, or downloaded it from the linkhttp:// /vlab. 1 P a g e

2 STEPS TO PERFORM BMSP TOOLS: (Follow the instructions given here for proper operation of the same, and click the buttons only when required.) STEP 1: First of all login window will appear, login through a valid username and password or perform functions offline by clicking on Work Offline. STEP 2: Click on BMSP Functions button to proceed further. STEP 3: From a choice of BMSP functions select any one to open, which is further divided into its sub parts. STEP 4: Select a BMSP function to perform. Buttons are provided with the name of main function selected to return back. STEP 5: Select type of signal, frequency, phase and other added parameters which are displayed in graphical format to perform a BMSP function. 1) Press Add to report, if performed experiment is to be included in the final report. 2) Press Theory, to view the formulas used in function, press Close window to resume. STEP 6: At any point of time to quit press Stop button. This will make the control jump directly to the questionnaire window. Answer the questions and submit to check result. STEP 7: Conclusion window will appear next. Comment remarks regarding the tools used which may be STEP 8: Last is the report window, take its print out or store. Press Exit to quit. Note for first time user: Before Performing any BMSP tool user should get registered at Virtual Lab of Biomedical Instrumentation website to get a valid Username & Password. 2 P a g e

3 INDEX TOPICS PAGE HOME.. 4 Login Window. 4 Welcome Window 5 BMSP Functions OptionWindow 6 General BMSP FunctionsWindow 8 (a) Signal Statistics.. 9 (b) Aliasing.. 10 (c) Convolution, Cross Correlation & Auto-Correlation. 11 (d) Power Spectrum (e) Histogram. 13 Transforms Window 14 (a) FFT (Fast Fourier Transform) & IFFT (Inverse Fast Fourier Transform) (b) DCT (Discrete Cosine Transform) & DST (Discrete Sine Transform) (C) Hilbert Transform (d) Wavelet Transform.. 18 (e) Chirp-Z Transform Filters&WindowsWindow.. 20 (a) IIR (Infinite Impulse Response Filter). 21 (b) FIR (Finite Impulse Response Filter) (c) Window Function Implementation (d) Signal Filtering. 24 (e) Median Filter.. 25 Sample Compression Window 26 Questionnaire Window.. 27 Conclusion Window 29 Report Window.. 30 Appendix P a g e

4 HOME Login Window- For first time users- Register on the virtual lab site following the linkhttp:// /vlab to create an account for logging, this is to be done only once. After creating an account, login through the same username and password For regular users- Since you already have a valid account, login through that Username and password. Click the LOGIN button to proceed further. Run button run the VI If you have not selected the network option than first stop the VI select network and again run the VI. NOTE: Please enter a valid username and password. 1. Biomedical Virtual Lab To get access to Virtual biomedical lab portal. 2. Select Network- If you are performing the experiment outside IIT Roorkee campus select Internet Else IIT R Intranet. 3. Live Chat- To chat with professionals for any guidance and support.

5 Welcome Window:- Welcome window will appear next. Press Perform BMSP Tools to perform BMSP Functions or logout if required to do so. On clicking Perform BMSP Tools a BMSP Functions Option Window will appear with following functions- 1> General BMSP Functions 2> Transforms 3> Filters & Windows 4> Sample Compression As shown on the nextpage.

6 BMSP Functions Option Window On left side of this window appears BMSP Function Options from which you can choose any function which again has many sub functions. On the right of this window appears a live video of the Biomedical Virtual Lab, with control options provided to change settings of the video. Click on any of the above functions to gain access to its sub functions or on HOME to return to welcome window. The subdivision is as follows- 1>General BMSP Functions 1(a) Signal Statistics 1(b) Aliasing 1(c) Convolution 1(d) Power Spectrum 1(e) Histogram

7 2>Transforms 2(a) FFT (Fast Fourier Transform) & IFFT (Inverse Fast Fourier Transform) 2(b) DCT (Discrete Cosine Transform) 2(c) Hilbert Transform 2(d) Wavelet Transform 2(e) Chirp-Z Transform 3>Filters & Windows 3(a) IIR (Infinite Impulse Response) Filters 3(b) FIR (Finite Impulse Response) Filters 3(c) Window Implementation 3(d) Signal Filtering 3(e) Median Filter 4>Sample Compression

8 1>General BMSP Functions Window- On clicking General BMSP Functions button from the BMSP Functions Options window the following window will appear Follow the instructions given on right side of the above window and choose from above general BMSP functions - Signal Statistics, Aliasing, Convolution, Power Spectrum, and Histogram. 1. HOME To return to the welcome window 2. BMSP Function Options-To select other BMSP functions 3. STOP- To exit and jump to questionnaire window.

9 1(a)Signal Statistics Window Select the input signal and set the frequency, amplitude and phase of the selected signal according to the Appendix 1and analyze the output parameters. This function calculates the following parameters: -Arithmetic Mean -Variance -Standard Deviation -Mode -RMS -Kurtosis -Skewness -Median -Minimum and Maximum of the input signal selected. Click General BMSP Function Options button to go back to General BMSP functions window.

10 1 (b) Power Spectrum Window: Select the input signal and analyze the output parameters. Two choices of power spectrum are provided: single sided and double sided power spectrum. Corresponding to the choice, spectrum modifies its peaks at the selected frequency. NOTE: The output is in normalized form. Click General SP Function Options button to go back to General SP functions window.

11 1 (c) Histogram Window: Select the input signal and analyze the output parameters. In this function a Gaussian noise function is generated by adding Gaussian noise to an input signal, whose standard deviation and mean can be varied. The generated Gaussian function s histogram is being plot with respect to bin values and amplitude. Click General SP Function Options button to go back to General SP functions window.

12 2>Transforms Window On clicking the Transforms button in DSP Functions Options the following window will appear. Follow the instructions given on right side of the above window and choose from above transforms- FFT & IFFT, DCT, Hilbert Transform, Wavelet Transform, and Chirp-Z Transform. 1. HOME Click to go back to the welcome window 2. DSP Function Options-To select other DSP functions click this button. 3. STOP- To exit and jump to questionnaire window.

13 2 (a) FFT (Fast Fourier Transform) & IFFT (Inverse Fast Fourier Transform) Window Select the input signal and analyze the output parameters. In this function the second graph shows the Fast Fourier Transform of the input signal and the third graph its Inverse transform i.e. the signal itself, and hence the graph will be same as the input signal graph. NOTE: The output FFT is in normalized form. Click Transform Function Options button to go back to Transforms window.

14 2 (b)dct (Discrete Cosine Transform) & DST (Discrete Sine Transform) Window Select the input signal and analyze the output parameters. This function evaluates the discrete sine and cosine transform (normalized) of the input signal and displays it in output graph. NOTE: The output is in normalized form. Click Transform Function Options button to go back to Transforms window.

15 2 (c) Hilbert Transform Window Select the input signal and analyze the output parameters. This function evaluates the Hilbert transform of the input signal and displays it in the output graph. Click Transform Function Options button to go back to Transforms window.

16 2 (d)wavelet Transform Window Select the input signal and analyze the output parameters. This function evaluates the wavelet transform of the input signal. From the drop down menu Wavelet Type select the type of mother wavelet such as Haar, db xx, bior xx etc. with level of decimations mentioned in adjoining numeric control Levels. Click Transform Function Options button to go back to Transforms window.

17 2 (e)chirp-z Transform Window Select the input signal and analyze the output parameters. This function evaluates chirp- Z transform of the input signal selected and displays it in the output graph. Click Transform Function Options button to go back to Transforms window.

18 3>Filters & Windows Window On clicking Filters & Windows button in SP Functions Option window, the following screen will appear. Follow the instructions given on the right of this window to perform functions in filters and windows tab and choose from above- Window Implementation, Signal Filtering and Median Filter. 1. HOME Click to go back to the welcome window 2. DSP Function Options-To select other DSP functions click this button. 3. STOP- To exit and jump to questionnaire window.

19 3(a) Window Implementation Select the input signal and analyze the output parameters with the help of following description. Windowing of the input signal in correspondence to a number of windows is done by this function. To perform it select any type of window from the list and see the output in windows implementation output graph. Click Filters & Windows Function Options button to go back to Filters &Windows window.

20 3(b) Signal Filtering Window Select the input signal and analyse the output parameters with the help of the following description. This function shows how filters can be used to reduce the effect of noise on a signal. To perform select the type of noise (for Gaussian noise set standard deviation), type of filter, its order and set the sampling frequency (higher than twice the frequency of signal). Distorted signal shows the noise added input signal and filtered output shows distorted signal after being operated on by filter (which is to an extent similar to input signal). NOTE: More is the sampling frequency more will be filtering it provides against noise. Click Filters & Windows Function Options button to go back to Filters & Windows window.

21 3(c) Median Filter Window Select the input signal and analyze the output parameters. This function applies median filter to the input signal chosen, by varying the left and right rank of the median filter. Click Filters & Windows Function Options button to go back to Filters & Windows window.

22 4>Sample Compression Window Select the input signal and analyze the output parameters with the help of following description. To perform this function select the type of compression method and press compression enable button to enable compression. And see the compressed signal (red) in graph which will vary according to the type of compression method selected. Click DSP Functions Option button to go back to other DSP Functions.

23 5> ECG Analysis On clicking ECG Analysis button in BMSP Functions Option window, the following screen will appear. choose from above - Filtering based ECG Analysis ECG analysis by spatial velocity method ECG analysis by wavelet method BMSP Function Options-To select other BMSP functions click this button.

24 5 (a)> Filtering based ECG Analysis Select the amplitude and phase of the selected signal To perform this function select the data file path and lead selection and then press load data and Analyse data.

25 5 (b)> ECG analysis by spatial velocity method Select the amplitude and phase of the selected signal To perform this function select the data file path and lead selection and then press load data and Analyse data.

26 5(c)> ECG analysis by wavelet method Select the amplitude and phase of the selected signal To perform this function select the data file path and lead selection and then press load data and Analyse data.

27 Questionnaire Window At any point of time while performing the functions on clicking Stop button the questionnaire window appears. On clicking Questionnaire the following window appears. Attempt questions and press Submit to return to questionnaire window. Click on Submit to proceed further. Click the Submit button to submit your answers and check your results later.

28 Conclusion Window Comment remarks regarding the tools performed, which will appear in the final report. Click NEXT to proceed to report section or BACK to return to questionnaire window.

29 Report Window The final report will appear in this window. Press EXIT to stop execution.

30 Appendix 1 General Instructions to perform any function or tool:- drop down menu. 2) For ECG there are various signals provided such as 30 BPM ( BPM stands for BEATS PER MINUTE),60 BPM, 120 BPM and so on. In addition with this artifact signals on 50, 60 Hz frequency and heart block diagram signals are also there. 3) For EMG (Electromyography, or EMG, involves testing the electrical activity of muscles), two channels are provided channel 1 and channel 2. 4) For Spirometry (meaning the measuring of breath) there are six data signals. 5) After selecting the kind and type of signal following procedure has to be done for results. 6) Add to report - Click this button to add function in use to the final report. NOTE: Just performing a tool will not show your experiment in the final report.

31 7) General DSP Functions Options / Transform Function Options / Filters and Windows Options - buttons will take control back to DSP Functions window. 8) Theory - On clicking this button a small screen will appear giving the mathematical formulae of the function in use. NOTE: Remember to close window once opened to proceed further with experiment. Stop - To exit at any point click this button, which will directly take control to questionnaire window.