Overview Whats in the toolboxes Learn basic techniques to use them Using MATLABs built in help and demos Setup Log in to your machines Start MATLAB Open a web browser and type in httptinyurlcomutatut ID: 637127
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Slide1
Introduction to MATLAB’s Signal & Image Processing toolboxesSlide2
Overview
What’s in the toolboxes
Learn basic techniques to use them
Using MATLAB’s built in help and demosSlide3
Setup
Log in to your machines
Start MATLAB
Open a web browser and type in:
http://tinyurl.com/uta-tutSlide4
Basic of signal sampling
MATLAB
stores signals in arrays – we are only storing samples
Nyquist
theorem F
s
>= 2 *
f
max
But what is the sampling rate in MATLAB?Slide5
Signal processing Functions in MATLAB
conv
filter
fft
i
fftSlide6
Time domain filters
sinc
FIR – windowing
fir1(
n,Wn
) returns row vector b containing the n+1 coefficients of an order n
lowpass
FIR filter with normalized cutoff frequency
Wn
IIR –
butterworth
butter(n,Wn) designs an order n lowpass digital Butterworth filter with normalized cutoff frequency WnSlide7
Signal Processing Toolbox
FIR filter design:
fir1 – uses windowing
fir2 – uses
idft
IIR filter design
butter –
butterworth
design
cheby1/2 –
chebyshev
designyulewalker – recursive designfdatool - GUISlide8
Things to do..
Try filtering out the high pass component
Mix in a 3
rd
sinusoid, and make a
bandpass
filter
Look up ‘
wavrecord
’ and ‘
wavplay
’ in MATLAB help and see if you can find something interesting to do with it and these filters.Slide9
Questions for now?Slide10
Image Processing Toolbox
Loading an image
imread
Displaying an image
imshow
Saving to a file
imwriteSlide11
Color images – are made up of 3 color components, can’t be processed directly
rgb2gray – converts to a grayscale image
im2bw – converts to a black & white image
process each color plane individuallySlide12
Spatial transforms
imrotate
imresize
imfilter
fspecialSlide13
Image registration & connected components
normxcorr2
bwlabel
imdilate
imerode
imclose
imopenSlide14
Image enhancement & restoration
imhist
histeq
medfilt2
wiener2Slide15
Accessing Demos
Type ‘demos’ at the command line
In the left sidebar, select MATLAB toolboxes
Expand a toolbox, and then any subcategoriesSlide16
Questions