Frequently used Matlab commands For loop : for variable = start : stepsize : end some Matlab statements end Example: for n=1:10 z=z+n; end If/then : If (expression that is either true or false) some Matlab statements else some Matlab statements end You can also use “elseif” to have more conditions to test. Sounds: [mysound, fs] = wavread( ‘filename.wav’ ) Convert a sound file into a Matlab vector Output variables: • mysound : vector for sound vector storage • fs : sampling frequency sound(mysound, fs) Playback the sound vector Input variables: • mysound: input sound vector • fs : sampling frequency of mysound wavwrite(mysound, Fs, ‘output name’ ) Convert the sound vector into a wave file Input variables: • mysound: input sound vector • fs : sampling frequency of mysound • ‘output name’ : name of output file (any name you like)Images: A = imread(filename,fmt) Convert figure file into image matrix in Matlab Input variables: • Filename.fmt : input figure Output variables: • A: image matrix in Matlab figure Creating a new blank figure for showing an image colormap(map) sets the colormap to the matrix map imagesc(C) displays matrix C , scale data and display as image imshow(A) displays the load figure matrix A Example: x=imread('lighthouse.jpg'); figure imshow(x)Plotting: plot(y) Make a linear plot of matrix y subplot(m,n,p) Creates an axes in the pth pane of a figure divided into an m-by-n matrix of rectangular panes. title Insert the title in the graph spectrogram (y, nwindow, overlap, nfft, fs, ‘yaxis’) Create a spectrogram of signal y Example: load handel; figure subplot(2,1,1) plot(y) title('handel in time domain') subplot(2,1,2) spectrogram(y, 256,128, 256, Fs, ‘yaxis’) title('Spectrogram of handel') 0 1 2 3 4 5 6 7 8x 104-1-0.500.51handel in time domainTimeFrequencySpectrogeam of handel0 1 2 3 4 5 6 7
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