MATLAB (MATrix LABoratory) is a numerical computing environment and a fourth-generation programming language. Use this tag with care.. see excerpt.

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How to reconstruct the signal which is subjected to FIR filtering - Matlab

I have a signal $x$ which is corrupted by Gaussian noise. The signal $x$ is convolved with a filter with coefficients $h = [1, -2, 1]$, to generate signal $y$. Now the signal is taken to Discrete ...
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2answers
32 views

2D-otsu algorithm in Digital image processing

I'm working on image project using Matlab & I heard about 2D-otsu algorithm as effective segmentation with low SNR and low contrast images, but I can't find enough information about it or how to ...
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15 views

Partial derivative simulation software

Is there any way I can simulate partial derivative either in matlab or any other simulation software . The drawback in MATLAB ( PDE toolbox) is expensive. Is there any alternative free simulation ...
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40 views

Ways to find three curves from palm image

I am asked to extract three curves from palm images. original image expected result. The curves has lower intensity than ...
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36 views

Not obtaining conjugate symmetry

In Matlab, I have set up input cosine signals with different frequencies and also time delayed versions of the signal. The idea is that a time delay would produce a phase shift in the frequency domain ...
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1answer
43 views

Generating a Sine Signal (for example a voltage sine wave) with changing frequency and changing sample rate (time)?

i have a measured signal (e.g. voltage sine wave) and i would like to generate a sine wave which matches this meausred signal (with the generated sine wave i remove the harmonics from my measured ...
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14 views

sine signal-->gaussian noise-->fading channel for SNR analysis

I'm new to matlab and need some help. I have a project whereby i want to to analyse the SNR of a sine signal which passes through an Additive White Gaussian Noise (simulating weather conditions) and a ...
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1answer
27 views

How to average coherences estimated using Welch's method in MATLAB

I'm trying to estimate the average coherence of discontinuous snippets of a signal in MATLAB. For Welch's spectrum estimates, the following works: ...
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1answer
28 views

Basics of waveform, how to define the zero point

Audio is a sequence of waveforms which have peaks, troughs, 0, just like below. How to define the x axis (y = 0) in the picture, how to choose the 0 point in the waveform since there are so many ...
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450 views

disadvantages of FFT, it can not extract enough frequencies without enough samples

Let's say sampling rate is $Fs = 44\mathtt{kHz}$, now I have $N = 2048$ samples, then I can get $N/2 + 1 = 1025$ frequencies. I'm confused by Matlab's FFT documentation that says the frequencies are ...
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20 views

Correct way to implement Discrete and Stationary Wavelet Transform?

Can someone please confirm if this is indeed the correct way to compute DWT: ...
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5answers
90 views

How to detect impulse like peaks - Matlab

I have a signal which is a matched filter output. whose values are given here: Amplitude values Input to this matched filter is radar return signals mixed with additive gaussian random noise. ...
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76 views

Frequency response of a filter - fft vs. freqz

I have designed my filter using firhalfband(N,Fo,A), which gives me the filter coefficients. Then I try to see the frequency response of it. I use these two ...
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17 views

algorithm Matlab function 'stream2' and 'stream3' use to compute streamline

Can anyone explain how the MATLAB functions: stream2(x,y,z,u,v,startx,starty) and stream3(x,y,z,u,v,startx,starty) compute stream lines from vector data u and v? In the stream2.m file, it calls the ...
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21 views

Clustering of overlapping windows (K Means)

I'm attempting the clustering of some of my data using a K-means Euclidean square method. I've broken the data down into small windows, 200 samples in size, but with a 50% overlap. I've chosen to use ...
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1answer
62 views

FFT Matlab - Meaning of Frequency Vector

I'm following a tutorial about the FFT. It's well explained but I don't understand the meaning of the frequency vector: ...
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1answer
39 views

Approximate a system frequency response with a filter in Matlab

suppose I know the frequency response of a (linear) model approximating a real physical system but only at a specific frequency $f_0$ (so basically I have a complex number whose module is the ...
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1answer
41 views

Make a movie from multiple images in MATLAB [closed]

I have 10 images in the folder say "D:\images\" named as frame1,frame2,...,frame10. I want to make a movie from the color images with frame rate as per choice.Also i want to save created video file in ...
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1answer
11 views

coefficients of farrow structure

what is the method for generating coefficients for farrow structure in matlab. I am designing a low pass filter using firpm but the output of farrow structure is not delayed.
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57 views

How to simulate AWGN in communication systems for specific bandwidth

I am trying to generate a AWGN waveform to add it to the signal of my simulated communication system. The operating bandwidth of the communication system is about ...
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1answer
31 views

How to normalize frequency in MATLAB

I know all about conversion of frequency from HZ to normalized frequency and from normalized frequency to angular frequency ,but I wonder how it is done in MATLAB. I have the following code: ...
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1answer
26 views

Demodulation with matlab

I am trying to listen VLF radio signals. I have a recorded wave file (download) and here is the frequency spectrum: I have produced this spectrum using this matlab code: ...
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2answers
58 views

How to visualize and understand Gabor filter using matlab

I am reading a paper, in which the author defines gabor kernels as : $$ \psi_{\mu,\nu}(x,y)=\frac{\lVert \mathbf{k}_{\mu,\nu} \rVert}{\sigma^{2}}\exp (-\frac{\lVert ...
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25 views

Time delay analysis in different binary sequences

I am extracting a property of a signal which I represent with either a 0 for absent or 1 for present. This property is extracted for each data point in a time series and in the end I am left with a ...
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30 views

Find Chessboard Corners using RANSAC in Matlab

I have a question: I want to implement an algorithm to find chessboardcorners out of set of given points. I have an image where I already have all the chessboardcorners there are, but also some ...
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2answers
97 views

Created Matlab echo signal: Is it an actual “echo?” Or am I just manipulating the signal to make it seem like an echo?

This is just an outline of what I did (assume that all my dimensions fit): ...
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1answer
28 views

how to visualize image segmentation using matlab

After clustering in image, I want to visualize the result. To do so, I first reshape an RGB image to 3*size. The result of BSMC is the set of indices after clustering. So I change the value at the ...
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36 views

What is purpose of correlation kernel? IIs it high pass filter or low pass filter?

I am research about correlation kernel and I have some questions that need your help. Let see the pp. 3302-3303 in the paper: Changyang Li, et al., Robust Model for Segmenting Images With/Without ...
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72 views

Train a Cascade Object Detector in MATLAB

I am trying to train a cascade object detector in MATLAB using the built in functionality from the Computer Vision Toolbox. I’ve taken 500 photo’s of the sole of my shoe. Every photo is taken from ...
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1answer
63 views

Finding phase angle via FFT

I am using the FFT to calculate the amplitude and phase of AC cos signal. Regarding amplitude it gives me an accurate result but I get wrong result for a phase: 6 degrees instead of 36 degrees. My ...
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2answers
59 views

Verifying channel response identity

If $x[n]$ is input signal, $y[m]$ is output signal, $h[m]$ is impulse response of the channel, then the following relation holds $\lvert Y(\omega)\rvert = \lvert H(\omega)\rvert^2 . \lvert ...
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1answer
88 views

What is correlation kernel and compare with gaussian kernel

I read a paper that said about correlation kernel that defined: $$W(x-y)=(α/1+d(|y − x|))$$ where $α = (\int(1+d(y − x)dy)^{-1}$, $(d(|y − x|))$ is spatial Euclidean distance from the central pixel. ...
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2answers
42 views

shifting sequences using Matlab

I'm reading this book and I came across a function to shift sequences. Mathematically, $$ y(n) = \{x(n-k) \} $$ if $m = n-k$, then $$ y(m+k) = \{ x(m) \} $$ ...
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52 views

Deriving finite impulse response for polylogarithm

As a part of my research i have to use the following z-transform in matlab 'filter' function so as to derive the convoluted signal from the original one. $$\frac{1}{{\rm Li}_{k}(z^{-1}e^{-b})}$$ ...
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15 views

Region splitting and merge

I am currently working on an image trying to apply split and merge technique. My main problem is selecting the best predicate for my image. Furthermore, because the objects in the image are quite ...
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1answer
56 views

Find B given A and impulse response of B/A

Here is a small MATLAB function that computes B in B/A given A and the impulse response h of B/A ...
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73 views

Denosing signal using soft and hard thresholding

Let us consider following code: fs=100; N=1000; t=0:1/fs:N-1; y=10*sin(2*pi*100*t)+0.5*randn(size(t)); plot(y) plot(t,y) I have applied following threshold ...
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1answer
79 views

how can I analyze a basic sine wave for its frequency phase and amplitude at a particular point in time in matlab

How can I analyze a basic sine wave for its frequency phase and amplitude at a particular point in time in MATLAB? Are there any tools to do that? I am trying to do additive synthesis of inharmonic ...
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104 views

Measuring audio Signal Similarities

i have recorded samples of lungs sound (person breath) signals from electronic stethoscope. how can i measure(in percentage) the similarity between two audio signals (lung sound), the general idea is ...
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35 views

denoising signal using DWT

let us consider following program for denosing signal using DWT ...
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47 views

I have run an FFT now want to get the mean value in the 8hz - 13hz range?

I have a matrix [66 x 100,000] (it's some EEG data, across 66 electrodes) and want to find the mean power in the 8-13hz range. How can I do this? I have so far: ...
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19 views

What data of images are given to kmeans clustering in matlab?

I am having 100 images in my database. I am using those 100 images as both training set and also test images. I have to make 5 clusters. I am using eigen faces (PCA) for feature extraction. What data ...
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1answer
72 views

An alternative algorithm for blob detection

Here's a sample image of my experiment which is to be processed for finding the information of all the blobs (centre, dimension etc.). Basically the image contains some noise, few bold lines, and of ...
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96 views

Image Reconstruction:Phase vs. Magnitude

Figure 1.(c) shows the Test image reconstructed from MAGNITUDE spectrum only. We can say that the intensity values of LOW frequency pixels are comparatively more than HIGH frequency pixels. Figure ...
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1answer
29 views

How can I run this MATLAB code snippet for the waveform synthesis? [closed]

Can you give me an example for this MATLAB snippet to generate sine wav with specified phase? ...
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1answer
31 views

How to find the frequency response of a communication channel from input and output symbols' functions in MATLAB?

I want to find the channel frequency response of a digital communications system. I have the functions of the input symbol (a triangle) and the output symbol - a distorted triangle: $$\dfrac{1}{1 + ...
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2answers
101 views

How to calculate step and impulse response at multiple sampling rates

I'm struggling with a basic concept. Suppose I have a system $y(t)=e^{-at}u(t)\ast x(t)$ and I want to plot impulse response and step response using Matlab conv() function at various sampling rates. ...
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1answer
50 views

Simulate a pulse of specific power

Suppose you produce a pulse x in discrete samples of duration dt each (e.g. in Matlab) according to a function. I was given some ...
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1answer
104 views

How do you change pitch with wavelet transforms in MATLAB?

I'm trying to increase the pitch of a wav file using MATLAB. (I don't expect it to sound very good, but I'm trying to figure out how wavelets in MATLAB work.) Here's what I'm doing: ...
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34 views

How are phase values able to capture motion from video?

I know that the phase spectrum contains most of the structural information about the image importance of phase. But I want to know more about importance of phase spectrum related to video signals. I ...