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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Fourier transform of an image

I am doing a project where I need to take the FFT and IFFT of a photo in MATLAB. There is a principle in optics where the intensity distribution from a lens is equal to the Fourier transform of the ...
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Whether the draback of Fourier transform will not allow to detect single moving object and avoid others from the traffic video?

I am working on a project in image processing which is based on importance of phase only reconstruction given in the answer by geometrikal in the link. Now ,I have detected moving objects from the ...
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2answers
24 views

Help for baseline drift removal/correction

I have signal as seen in the picture. It has high frequency noise and drifting baseline. I am able to remove the noise in MATLAB but I am not sure what can I do about the drift. I would like the ...
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1answer
48 views

Reconstructed signal [on hold]

Someone can help me. I generate a gaussian pulse signal with $f=2 MHz$ and I apply the FFT. After that I select all frequencies above $-100 dB$ and I try to reconstruct the signal. I created this code ...
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17 views

Matlab : Help in understanding CRLB and implementing for channel estimation

Paper : Cramer-rao bounds for semi-blind, blind and training sequence based channel estimation download link presents the Cramer Rao lower Bound (CRLB) for deterministic and Gaussian symbol model. ...
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31 views

What is spectral subtraction? [on hold]

I have to write some simple examples in Matlab which use spectral subtraction. These examples will be included in a paper to help a friend understand spectral subtraction. But I don't know where to ...
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0answers
20 views

Effect of Pulse shaping on BER

am trying to implement OQPSK modulation with half sine pulse shaping. If I simulate the OQPSK modulation without pulse shaping, the simulated curve is similar to the theoretical value. However, when I ...
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1answer
32 views

Comparison between 2 images in Frequency domain

As you can see there are 2 images from the Tom and Jerry cartoon program. In the 1st image both Tom and Jerry are present. But in the 2nd one,only Tom is present.Now,we can clearly see this ...
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1answer
19 views

How to find first 25 coefficients of DCT in Matlab?

I need first 25 x 25 coefficients of DCT to encrypt an image in Matlab. How do I obtain them ? I used this code to compute DCT of an image : ...
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1answer
36 views

Sampling frequency and oversampling factor

A quite naïve question. I need some clarification regarding choosing the sampling frequency and oversampling factor. The scenario is as follows: I have an OQPSK modulated sequence with symbol rate 2 ...
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1answer
44 views

How can I move a signal in frequency so that it ends at the frequency zero?

I am trying to move a signal to 0 in the frequency domain but I am not sure how to do it.
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0answers
9 views

Is affine the right transformation for coordinates change

Ill begin by describing my problem: i have a video, which was used in a tracking program. In that program the object being tracked receives per frame X,Y coordinates which are not the same as in the ...
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0answers
10 views

How to combine SURF and Harris points

As we know at Matlab, there is function to detect Harris or SURF feature individually. Then I need to combine these two list of features from both the Harris and SURF to make the matching more ...
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15 views

FIR/IIR approximation of known frequency response

I have two different sets of data from compatible signal sources but recorded off two different transmission line characteristics. I am trying to equalize out the transmission line in the two data ...
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0answers
15 views

error using vertcat when finding cross-correlation [on hold]

I got an assignment in finding delay using cross-correlation between two audio signal that we recorded in MATLAB. This is the code : ...
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0answers
9 views

How to calculate Coherent Change Detection?

I have two images which I wish to compare the difference between using coherent change detection and I'm having some trouble figuring out how to apply these signal processing equations to my data in a ...
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0answers
61 views

MATLAB, recover a signal that has a cosinusoidal interference and that has been AM modulated

I have a signal which has been AM modulated but the channel also added a cosinusoidal interference A cos(2 * Pi * f0 * n * Tc + Phase), at the same ...
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0answers
41 views

Perfect system identification or am i doing something wrong?

I am using MATLAB to identify a system. The problem with my method is that my result is perfect. I get a nearly 100% fit, which make me wonder if what I am doing is correct. I feed a sine sweep with ...
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2answers
48 views

Is this code for doing a moving average correct?

Is this code for doing a moving average correct? y=conv(x, ones(1,100)/100); I want to filter my speech signal with moving average filter in code. I think that ...
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0answers
8 views

How to offline classify EOG signal generated from eye movement?

I have the sample of EOG sample data in Matlab format in three column matrix (time,horizontal channel, vertical channel) and I want to extract the pattern of the eye movement from that sample which ...
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2answers
49 views

Am i performing Sinesweep correctly?

I am bit unsure whether i am doing i sine sweep correctly. I am feeding my system a sine wave with f hertz within a given time interval and log its output. And then i do the same for another ...
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0answers
9 views

Energy-based speech recognition [duplicate]

I have a noisy recording with individual letters spoken. In a spectrogram view of the audio, the letters have higher energy. What can I use to isolate them? I'm fine with any tool.
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1answer
81 views

Matlab : Proper estimation of weights and How to calculate MSE for QPSK signal for Constant Modulus Algorithm

I had asked conceptual Question about Constant Modulus Algorithm. I am implementing the simple steps of the algorithm, as I do not have the cma() built in ...
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0answers
31 views

Implementing xcorr() in the time-domain

This should be straight-forward. It is proving not to be. I want to implement xcorr in the time-domain (as it is usually defined). Why does the following MATLAB not producing the same plot as when the ...
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2answers
47 views

Noise removal from audio using FFT/Spectral editing

I have a noisy recording with some letters spoken out loud. I've noticed that the noise is easily recognizable when looking at a spectrogram of the audio. Is there anyway to set a power/frequency ...
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2answers
36 views

Upsampling by zero padding or duplicating sequence

I need to upsample a 2 MHz signal by a factor of 3000 to convert the OQPSK modulated baseband signal to passband. When I upsample by duplicating the elements in the sequence, I seem to get less error ...
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29 views

I am trying to transform a signal into multiple images but the images are not clear

I have a signal that contains three distinct images, this means that I have three frequencies or peaks, and each one corresponds to a picture. I have a function that converts a signal into an image. ...
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2 views

Can we use Data Fitting for Optical Chromatic dispersion compensation

Can we use Data Fitting for Optical Chromatic dispersion compensation any matlab example from where I can learn how to do it .
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1answer
16 views

Result of a specfic plot

If we plot for example the relation between the probability of False Alarm (pfa) and the threshold. The threshold is in x-axix, while the $log _{10}(pfa)$ in y-axis. If I get for example the ...
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1answer
30 views

KLT tracker implementation

I'm working on a object tracker based on KLT algorithm using matlab. Can anybody guide me how I can find the features and calculate the distance in the sequence of the frames? Thanks.
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22 views

Frequency response of OQPSK Modulated Signal

I am a little confused as how the frequency spectrum of an OQPSK modulated signal would look like. I have a DSSS that is OQPSK modulated with a bandwidth of 2 MHz. The modulated signal has complex ...
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0answers
29 views

How to show the time history of a signal down-sampled ? under the rate of 25Hz & 40Hz and find its DFT analysis?

How to show the time history of a signal down-sampled under the rates of 25Hz & 40Hz and find its DFT analysis using Matlab ? The sample signal is in a data file (sensor_data.mat) its sampling ...
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21 views

BER of OQPSK Modulation

I am unable to find out a formula for the BER for the OQPSK Modulation. Currently, I am using the berawgn function from Matlab to calculate the BER for OQPSK but I am looking for an expression for ...
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1answer
45 views

Effect of frequency shift on a sound signal

I had two sound files and did the following to it: ...
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1answer
38 views

What windowed Sinc might be closest to a Parks–McClellan low-pass filter?

In another question on dsp.stackexchange, a statement was made that the output of MATLAB firpm() or firls() for an anti-alias low-pass filter was "close" to the coefficients of a windowed-Sinc ...
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2answers
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FIR Filter matlab command

i'm trying to understand the fir1 filter but i still don't get it. For example here i got an audio signal that i consider noise, i'm passing it through a low pass filter. ...
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2answers
30 views

How to determine the filter type of a discrete frequency spectrum

I have the discrete impulse response of a filter and i want to determine which kind of filter it is by using the DFT. The impulse response is: h0 = [0,1,2,1,0] ...
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1answer
27 views

what is the delta parameter in scal2freq?

I am running complex morlet (cmor1-1.5) wavelet transform. I want to have the transformation for the range of [1,150] Hz whit step of 1 Hz. I want to use ...
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2answers
63 views

MATLAB frequency magnitude spectrum

I am using the following code to generate four sine waves using a sampling rate of 8000. ...
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1answer
21 views

What are the units of amplitude of my ultrasonic recording equipment

I'm not familiar with the topic of sound. I have ultrasonic audio recordings sampled at 250kHz (16bit) in WAV format. The equipment used to record them is linked here: ...
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2answers
38 views

FIR Filter phase shift and stability

I designed an FIR highpass filter which is causing a phase shift to the output. The output signal is also not stable (?) on start. Are these normal or am I doing something wrong? If these are normal, ...
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0answers
48 views

Implementing Optimal Crosstalk Cancellation with matlab

I am trying to implement a crosstalk cancellation in Matlab, more precisely part of : Optimal Crosstalk Cancellation for Binaural Audio with Two Loudspeakers ...
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0answers
49 views

1-D deconvolution in Matlab

Suppose that I know the output and the transfer functions of a system and I would like to calculate the input function using deconvolution. To get a grasp of the idea I have created a simple ...
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2answers
56 views

adding noise to a signal

I have an audio file. I took an extract of the file called variable "CALL", and I took another extract from the file which is just filled with background noise, called "BACKGROUND". Using matlab, I ...
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1answer
56 views

Matlab: if given nothing but an audio file, how do I modify it to produce incrementally lower signal to noise ratios?

I have an audio file with a high sampling rate of 250khz. It contains animal noises. I've built a program which counts all the animal noises. However, I want to find out how robust the program is and ...
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1answer
102 views

Compare phase and magnitude spectrum results of 2 Images [duplicate]

I have read that from Fourier transform we obtain magnitude and phase spectrum. The magnitude spectrum tells you how strong are the harmonics in a image and the phase spectrum tells where this ...
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1answer
30 views

DSP finite impulse response (MATLAB)

I designed the filter below on paper: FIR low pass type 1 length 3 alpha = 6 beta = -12 allow freq. <= 0.1rad/sample blocked freq. >= 0.4rad/sample To ...
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0answers
16 views

Completing an image edge using MATLAB

I'm trying to complete the right edge of the rectangle in the following image: The approach I've tried involves running a Sobel filter for edge detection on the image rotated by 45 degrees, ...
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1answer
21 views

how to add two images in one, next to each other

I have two splited images from diference matlab files. Now i need to merge them, near to each other. I tried supblot, imadd,cat methods, but nothing works. Please help me. rezult after sublot ...
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1answer
25 views

Zero-padding a plot

I am using the following code to plot a window: m = ((33-1)/2) n = -m:m w = 0.54 + 0.46 *cos(pi*n/m) stem(0: numel(w)-1, w) This is giving the following plot: ...