Questions tagged [zero-padding]

Zero padding consists of extending a signal (or spectrum) with zeros to extend its time (or frequency band) limits.

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How do I calculate peak amplitude of the signal components after zero padding and FFT?

I am learning about DFT and trying to apply it to some audio processing. I am new to DSP but experienced in programming and have some background in math and physics. The FFT algorithm I use (lomontFFT)...
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1answer
27 views

Different type of padding in image?

I want to implement a gradient operator on an image in Matlab. Should I have to pad the image before its implementation? How do I decide which padding to use e.g. whether to use zero-padding or ...
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1answer
104 views

Zero padding in frequency domain, any tricks to speedup?

there are many situations when one has to carry some operations on spectra, like splitting a spectrum Z wide in two Z/2 spectra, or vice versa merging two Z sized spectra in a 2Z sized one. The only ...
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1answer
239 views

Matlab: Different 1-D FFT results with and without zero-padded

Recently I am implementing FFT with C code. So I use Matlab for algorithm verification. As Radix-2 FFT was chosen, I've learned that zero-padding technique could help to reach 2^N limitation without ...
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0answers
226 views

Windowing a signal by using Hanning / Hamming or… zero padding?

My question is about the use of Hanning or Hamming windows versus "square" windows. In my understanding, I will use a Hanning or Hamming window to limit the spectral leakage. But, on the second hand, ...
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136 views

When Is a Power of 2 FFT Slower than Smaller Sized Non Power of 2 FFT in MATLAB

Knowing that computing an FFT is faster if the amount of samples is a power of 2 I have always tried to pad the inputs to Matlab's FFT with zeros until the next power of 2 is achieved. Matlab's ...
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0answers
543 views

Estimating The Time-delay using the Phase of the Cross- Correlation function

I am relatively new to time delay estimation. I am working on a project where I am estimating the time-delay from the phase of the cross-correlation function (CCF), since it is more reliable in ...
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0answers
21 views

Complex demodulation zero-padding and frequency shifting/truncation errors (Python)

I've been stuck trying to make a complex demodulation of a signal using the FFT work. I am currently trying to achieve the following: Window the time signal with a hanning window Add zeros to the ...
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0answers
31 views

Zero Padding in image reconstruction

I need to zero-pad the image for a better reconstruction but according to my project details, I will be given a Fourier-transformed image so can someone tell me how to pad the image in such a ...
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0answers
35 views

Meaningfulness of Frequency Spectrum for Classification

I just started to dive into signal processing due to a free-time project. Therefore, this is my first question here, for which I searched many previous threads, but couldn't find what I was looking ...
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0answers
48 views

How much zero padding I should do to an audio signal before fft?

I was working on project and I need to do fft to my audio signal. I was going through a code and found following line. Can anyone explain me the line of code. ...
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27 views

Adding zeroes in between the samples of a discrete frequency domain leads to both zero padding and scaling

I won’t show ALL the calculations, but I’ll describe the problem fairly enough to understand. We’ve been taught that upsampling on one domain leads to padding zeroes or added time period which is zero ...
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40 views

Zero-padding or Interpolation in 3D FFT

I'm trying to perform a FFT of a 3D regular grid and then compute the bin average (in spherical shell bins) of the Fourier transformed grid. The problem is that the resulted vector is very noisy as I'...
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21 views

How to optimize padding and truncating of signal

I 6000 signals that vary between 3000 and 30000 in length In the figure under you can see that most of the signals are of length 5000. So I decided to pad and truncate all signals to 10000 and feed ...
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61 views

Cepstrum calculation with 5-smoothing zero padding

I am trying to compute cepstrum of a signal x An implementation of this in python is: ...
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1answer
172 views

Zero padding issue - cut the buffer

I have some issue with zero padding. It's probably because I don't understand it enough. I have buffer size set to 400. And I use radix-2 fft. So I take the input signal 400 samples, and add to them ...
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0answers
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Autocorrelation and FFT : avoid zero-padding

Some posts evocate the computation of convolution or cross-correlation using FFT and zero-padding the temporal signal. I want to compute the autocorrelation of a 3D array using FFTW (2 dimensions are ...
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399 views

FFT frequency domain averaging and zero padding

I'm trying to get the average frequency response of an entire piece of audio by splitting it into segments, doing an FFT on each one, and averaging the magnitudes together. Its working great until I ...
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1answer
42 views

The impact on the frequency of adding zero samples and non zero samples

Can someone give me a brief explanation of what is going on in here? I struggle to understand the full differences between the impact on the frequency of added zero samples and adding samples which ...