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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Calculating incoherency in compressive sensing

CS is based on a choice of a sensing basis Φ relative to a representation basis Ψ.There are many well known pair matrices for Φ and Ψ like random Gaussian and FFT, and also they should have low ...
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35 views

Rayleigh BER in Simulink

I'm using the Rayleigh Channel in Simulink but I can't calculate the BER. I always get values near to 0.5 which doesn't make sense (even using high EbNo values). [In this simulink model][1] I found a ...
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1answer
67 views

correct way for Zero padding

I am doing simulation of FMCW radar. I am applying signal processing chain on raw radar data. Here in the code below, I am taking fft of data and plotting it. ...
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23 views

Accurate Noisy Signal Filtering

I'm looking for some ideas to filter a noisy signal. my sampling Condition is : ...
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16 views

Memory and bookkeeping for realtime window-overlap-add (WOLA)?

Given a realtime embedded system with input samples x(n) coming from an ADC, what is the pipeline to output y(n) if ...
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20 views

What does imfilter do? (Matlab)

I've been looking online but I can't seem to find an explanation that I can easily understand. I am working on a demosaicing assignment which uses the imfilter command in matlab. Specifically, I am ...
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10 views

How to find the security of an encryption technique?

Is there any equation to show that a new encryption is more secure. Since it is required for theoretically showing the result. The encryption is implemented using matlab. Plz help me to find the ...
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2answers
36 views

How can JPEG 2000 be implemented using MATLAB? [closed]

I am new to image processing and image compression. It would be great if someone could specify which functions would be useful for doing so.
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0answers
17 views

what is magnitude responce at ω = π/2M for freqz function [duplicate]

what is magnitude responce at ω = π/2M.Code Given is ...
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13 views

How to reduce reconstruction noise from a filtered back-projection reconstruction of a circularly symmetric image?

I need to perform tomographic reconstruction of an axially symmetric object. Because of the axial symmetry only one projection of the object (one angle) was taken. I implemented the filtered ...
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1answer
31 views

Difference b/w freqz and fft

Since both fft ,freqz are used for finding the frequency response of digital filters. the frequency response using freqz function is given below and frequency response using fft function is it ...
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36 views
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20 views

If I build a low pass gaussian filter in the frequency domain should I also normalize it with the sum of the filter coefficients?

I saw two examples of applying a Gaussian low pass filter to a Matlab image: one- when the filter was built in the space domain and was normalized with the sum of the filter coefficients, and another- ...
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45 views

How to extract text from a scanned document?

The task I am facing is extraction of rotated text (any angle) from a scanned image(attached Image). The image contains a blue sticker on it and need means in extracting the text (printed text) from ...
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14 views

How to deal with Imaginary Value of Fast Discrete Curvelet Coefficient?

I want to classify the mean, energy, std, and entropy of discrete curvelet coefficients(wrapping) with Neural Net. But Neural Net can't deal with imaginary value. I have 2 option, either make it real ...
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17 views

Multirate filtering attenuates frequencies at overlap

I am trying to build a filter with different frequency bands in Matlab. I would like the filter to be as invisible as possible, but after the filtering, a great amount of frequencies are being ...
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1answer
20 views

Simulink Floating-Point and Fixed-Point Modeling

I have not used Simulink extensively. I would like to know how to determine if a model is fixed-point or floating-point. Also, how to convert from fixed-point [back] to floating-point. The posts on ...
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1answer
44 views

Fourier series calculation [closed]

I have tried to solve, but do not know if the answer is correct or not. A person has a periodic voltage input to a circuit. The input repeats itself every 0.02 seconds i.e. the fundamental period is ...
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7 views

Room Impulse Response for CHiME speech database

Where can I find the .wav file or a MATLAB plot for the Bin-aural Room Impulse Response(BRIR) that is used to create the CHiME speech database? http://spandh.dcs.shef.ac.uk/chime_challenge/data.html ...
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1answer
44 views

Per Window Normalization

I have PPG signal that should be normalized, with offline processing I'd just do $z$-normalization, $$ \displaystyle \frac{x- \mu_x}{\sigma_x} \quad \text{where } x \text{ is the signal.} $$ The ...
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2answers
44 views

Find frequency/phase response of a microphone

I am trying to find the frequency/phase response of two cheap microphones bought off Ebay. Basically, I want to graph the frequency responses and phase responses of both microphones on the same axis ...
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6 views

The interpolation formula for building a steerable 3D filter of a second-order Gaussian

I am trying to write the Matlab code for a steerable 3D function, but cannot find anywhere the interpolation formula between the spherical harmonics. I researched on the internet, but really didn't ...
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0answers
10 views

Why do I have to duplicate the labels used for the classification process?

I'm using the BCI Competition dataset IV 2a. I'm working on Left & right hand movement. I extracted data of channels (Fz,Cz,Pz). I filtered data [8-30], then normalized it. I calculated the ...
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5 views

Comparing the spatial frequency between groups of images

I have 2 groups of images, and I want to compare these groups based on the spatial frequencies of the images. In the end, I'd like to be able to say "group A is/is not significantly different from ...
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3answers
81 views

detrending in real time

I have a certain signal that has a linear trend that should be removed. The problem is that the signal needs to be processed in real time(sampling rate is 20Hz). If I only apply the detrending per ...
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1answer
28 views

How to use ImageNet Database in Matlab [closed]

How to use ImageNet Database in Matlab for object classification or recognition? I didn't find any tutorial which could practically tell me how to train images on ImageNet database and classify the ...
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12 views

How to take IFFT of Connes Window?

The Connes Window function is defined as : w(f)=$(1-(\frac{f}{ \Delta f})^2)^2$ for $f<|\Delta f| $ w(f)=0 otherwise The inverse fourier transform of this function can be ...
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22 views

eliminating white areas without sharp boundaries

I have images of following type: and As one can see, in the corners of the images there are white areas which don't have sharp or well defined boundaries; the intensity gradually decreases. ...
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1answer
28 views

what is the concept of matlab function polynomial interpolation?

I am curious about matlab function. Can you tell me why does not it do good approach to using of matalb functoon except for speed reason? Is there any other reason to using polynomial utility?
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16 views

Change of group delay scale in matlab

I have a question concerning the conversion of a matlab plot group delay scale. The book Digital Filters for Everyone, 3rd edition, by Rusty Allred has a matlab plot of group delay in samples vs. ...
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18 views

Variation of Pulse width with center frequency in Pulse Compression technique

Assume a chirp with BW = 1 Hz (frequency range 0-1 Hz) for a period of 700 sec. The pulse compression technique (obtained through auto correlation function) applied on the chirp generates a pulse ...
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17 views

Exact indices of fft

Lets consider the cyclic frequency transform and lets try to make it so that the transform of the function is itself. ...
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23 views

How to do wavelet decomposition in Matlab?

I want to apply a wavelet decomposition on a vector x using Matlab wpdec function. How can I retrieve from this the approximation and detail coefficients at different decomposition levels?
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1answer
45 views

How to Flip Spectrum Around DC?

Is it possible to flip a signal's spectrum around DC? I have a simple spectrum that I made up (MATLAB code): ...
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1answer
24 views

Removing DC offset and ensuring zero-sum for 2D filter

I'm working on project where I'm using Independent Components Analysis (ICA) on NxN patches from images to separate components in an image signal. Each column of the resulting MxN^2 unmixing matrix is ...
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21 views

What's the optimal filter size for a 2D Gabor filter

I started to experiment with Gabor filters to extract various image features from usual camera snapshots (that's the image domain: everyday snapshots with a very diverse range of subjects). ...
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49 views

Additional peak after resampling

I prepared a Matlab script, which re-samples spectrum from 24kHz to 20kHz. When I used up-sampling, a fir filter, and then up-sampling again at the end, I get an additional peak at 4kHz which is not ...
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3answers
78 views

How to calculate the frequency of a signal without knowing the sampling frequency using Matlab

I have a signal and I am using Matlab command pwelch to calculate the frequency of the signal, but the frequency I obtained is changed as I change the sampling frequency. For example, when using ...
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2answers
60 views

Is matlab fft faster for real input?

I realize that matlab fft is twice as fast for real input. But does matlab fft take the fact that the transform will be conjugate symmetric into consideration? Since the input is real, it would have ...
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66 views

Forward and backward filtering

I have an input sequence $x(n)$ and impulse sequence \begin{equation} h(n) = \begin{cases} 0 & \quad \text{when } n = 0 \\ .239052 & \quad \text{when } n = 1 \\1.3357\exp(-0.650286n) & ...
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5 views

Generalizing Matlab Hough Function

I am trying to modify the MATLAB hough() function so that it handles grayscale images. for that I started with openening the file ...
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47 views

Least Square Channel Estimation Technique

A communications channel is modeled by a finite-impulse-response (FIR) filter: $$y[n] = Hs[n] + w[n]$$ where $H$ is the channel coefficients, $s$ is the binary source and $w$ is AWGN A least Square ...
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52 views

How to use wavelet decomposition for feature extraction (of fMRI images)?

I have a dataset consisting of fMRI images (from mice) which are divided into 4 groups (different drug dose levels applied). Each fMRI image is 4D, that means each voxel is a time series. For each ...
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2answers
51 views

applying single pole filter to simple signal

How to apply single pole filter to simple signal fs = 500; ts = 1/fs; t = 0:ts:1-ts; fc = 50; S = cos(2*pi*fc*t);
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55 views

What is Single pole filter?

Can anybody tell me why do we use single pole filter? And may be an example of Single pole filter in matlab. Good literature recommendations are also welcomed.Moreover, that would be good if anyone ...
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2answers
60 views

How can I extract a sinusoid from a very noisy signal for computing the phase shift?

I have done some measurements and I got two very noisy signals. I want to extract a certain sinusoid from the signals and I want to compute the phase shift between them. I made some simulations and I ...
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0answers
14 views

Matlab fspecial disk: Algorithm reference or algorithm logic

I'm trying to figure out how the fspecial function works to create a discrete disk in Matlab. This function is an averaging filter that arises in an image processing environment. The Matlab algorithm ...
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2answers
38 views

Frequency response of a (rectangular) integrator

A very simple question which can't really figure out: I have a simple discrete time rectangular integrator with Z transform H(z) = 1/(1-Z^(-1)) Plotting the frequency response with Matlab using ...
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1answer
33 views

Why standard Waveform from audio out gets distorted when i reduce the amplitude?

In my attempt to generate a standard sine wave out of a sound card, i started using matlab which has a function soundsc for scaling the output ...
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67 views

Frequency Shifting in MATLAB

I am currently attempting to demodulate an audio file using MATLAB. After taking the fft of the signal, I receive this: After some more coding, I found the following values: Fs = 44100; Window ...