Questions tagged [convolution]

Convolution is a mathematical operation on two functions f and g, producing a third function that is typically viewed as a modified version of one of the original functions.

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Would anyone be able to help out with the following discrete convolution question?

I have been trying to attempt this question for quite a while and I am not sure how to approach it. Would anyone be able to help out with the working?
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Convolution a 3-D signal with 2-D signal

I have a 3D signal $M(x,y,t)$ and I want to do convolution with signal $G(x,y)$ and $Et(t)$, I mean, how to calculate this Convolution below in Matlab? $$A(x,y,t)=M(x,y,t) \star G(x,y) \star Et(t)$$ ...
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Solving a Convolution Problem

I was unable to solve a convolution question.Question is attached herewith. I don't know how to initiate for solving the problem and what is the final expression that prove the convolution of a top-...
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29 views

measuring how much signal corrupted by passing from a medium [closed]

I am looking for a measure to report how much a signal has corrupted by passing a medium. Suppose we have a signal 2Hz and amplitude ...
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164 views

Filter design to realize Cauchy product

I come from Computer Science so please pardon for my possibly wrong terminology. I need to design a filter which has coefficients $$h_0, h_1, \ldots, h_n, \ldots \quad\text{such that}\quad h_0 > ...
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Recognize irregular repetition of unknown feature (stamps at random locations)

I have an image which is generated by convolution between (1) a simple small patch and (2) larger image composed of localized point-like features (e.g. slat-and-pepper noise, sum of shifted $\delta$-...
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358 views

Two real time signals convolving

This might be a stupid question but is it possible to convolve two real-time signals together? I know that generally for running convolution you have the IR and the block of the real time signal and ...
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47 views

Deep learning model for phone recognition - issues with dimension the model

I seem to have some problems understandind how the model described in this paper has been designed This is what is written about the model dimension.. ...In these experiments we used one ...
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1answer
125 views

Is sampling a Fourier transformed signal and fourier transforming a sampled signal the same?

I'm having a hard time understanding an assignment that states: Draw the complex spectrum of the sampled signal $f(t)$ (periodic and continuous). Do this, by first calculating the Fourier ...
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911 views

Implementing a Band-Pass Filter from Scratch

I am trying to implement a band-pass filter from scratch. Here is an article which I thought explained the nuts and bolts of how to build one; the author combines a low-pass with a high-pass filter (...
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2k views

Parameters of Gaussian Kernel in the Context of Image Convolution

Hi Everyone i am new at image processing. I copy code from this website, I have image $600 \times 480$ gray scale. What will be the value of standard deviation or $\sigma$? What will be the value of ...
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Applying a frequency filter in dB onto an audio wav file in the frequency domain

I am working on a university project consisting of a C program supposed to apply a correction of the isophonic curves to an audio PCM file. So far, I have managed to code the most part of it (read/...
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558 views

Prewitt operator and central difference?

When taking the gradient of an image one can do $I * \begin{bmatrix}+1 \ 0 \ -1\end{bmatrix}$ (x direction). As I understand this is basically applying central differences in the x direction, $\...
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Fastest way to subtract known music tracks from live videogame audio stream

I want to isolate video game "action" sounds from the video game soundtrack. Given all ~20 songs, I'd like to filter them out from any live audio stream during gameplay. What is a fast and robust way ...
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Convolution and Deconvolution in C

I understand the theoretical foundations of convolution, but now that I'm trying to program it I'm having some issues conceptually. Say I have two blocks of 64 audio samples each. I also have access ...
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1answer
120 views

Given a Horizontal Derivative Kernel What Would Be the Output Image?

Hi, im solving this problem and everything went well until i went and solved the position p(5,3) and i got the answer of 0. However, the solution guide lists the solution as 150 which is pointed at ...
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293 views

Filtering White Noise to Generate Harmonic Signal

I have studied convolutions and filters a long time ago. Today, I am trying to review the basics using some notes of mine, but I am finding difficult to solve easy problems. Since I don't have ...
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487 views

How to Do Convolution a 2D Signal (Image) and Result of Convolution of Two 1D Filters?

Assume a 2-D signal (i.e., some image). Load image and assume it to be signal x. Next assume that instead of having a 2-D filter you have two one D filters $$f_1[n] =\begin{bmatrix}0.25 && 0....
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Overall system IR: How to do arithmetic with $\delta$ functions?

When finding the overall system impulse, how to do arithmetic with $\delta$ functions? E.g. \begin{align} h[n]&=h_1[n]\star h_2[n]\\ &=\sum_{k=-\infty}^{\infty} h_1[k]h_2[n-k]\\ &=\sum_{...
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Understanding an alternative representation for the difference equation of a FIR filter?

I recently solved a problem which required that I compute the convolution of an input signal with the impulse response of a filter. I got the resulting discrete signal which is verified to be the ...
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Deconvolve using divsion of FFT of shifted signal in time domain

I have FFT of two signals. Y=120 , Y1=80 Hz. to convolve in time domain I can convolve them using their ffts. as ...
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674 views

Using Convolution as Feature Extraction

I am now studying image processing in my spare time. My understanding of convolution is about 'response to a specific filter': When we have a raw image, or raw signal; and a filter, aka kernel; we ...
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811 views

Why does reversing the order of these two transfer functions give me different outputs?

Consider these two systems: \begin{align} &u\ {\longrightarrow}\boxed{s}{\longrightarrow}{\boxed{\frac 1s}}{\longrightarrow}\ y\\ &u\ {\longrightarrow}\boxed{\frac 1s}{\longrightarrow}{\boxed{...
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Applying Image Filtering (Circular Convolution) in Frequency Domain

To filter an image we can: Use a 3x3, 5x5, 7x7, etc. filter, that is convolve the image and the filter in the space domain. Use a FFT on both the image and the filter, multiply them together in the ...
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706 views

Is periodic convolution same as circular convolution?

I know exactly what is periodic convolution. But i don't know if circular convolution means to be the same thing!
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Convolution of Two Kernels [OpenCV]

I've been completely stuck on a portion of my assignment for a few days now. After plenty of searching around, I have been unsuccessful in discovering information that leads me to the correct solution....
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826 views

How to implement the $\tt conv(x,h)$ in MATLAB without using loop?

I'm trying to calculate convolution of two given vectors in MATLAB without using loop, and of course without the function conv itself, but I can't remove the last ...
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933 views

Convolution of two large signals in MATLAB

I need help regarding convolution. I am trying to convolve a signal which is $15\textrm{ ms}$ long, and the sampling frequency is $10\textrm{ GHz}$. I need to convolve it with a rectangular pulse, ...
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Can this robot trajectory smoothing function be expressed as a single convolution?

I have an Nx3 matrix of poses (x, y, theta) that I need to apply an algorithm on which will cause the trajectory to be smoothed. I am interested in performance and so would like to improve efficiency ...
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1answer
98 views

Delayed impulse does not delay spectral response

Inspired by Dr. Sarwate's answer to the question How replicas are formed in Frequency domain when a signal is sampled in Time Domain? , I decided to see for myself the underlying concept. I ...
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570 views

Comparing band-pass filters and convolutional kernels?

I am currently working on extracting features for speech recognition purposes. I wanted to try an approach similar to MFCC features in which the center frequency of each band pass filters are placed ...
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1answer
395 views

Time-spread multiple echoing of audio signals

I have been reading papers related to adding echos into digital audio signals recently. I guess I understood the logic behind, yet I guess I am still having lack of DSP knowledge to figure out ...
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421 views

Fourier convolution of a histogram

Notation: $\mathcal F\left\{a\right\}$ denotes applying the discrete forward Fourier transform to the histogram $a$. Similarly for $\mathcal F^{-1}\left\{a\right\}$ and the discrete inverse Fourier ...
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Control systems and convolution

I think i am not understanding the concept of convolution well. Lets say we are given a system impulse response in the S-domain, and we have implemented a controller $G_c(s)$ that will adjust the ...
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Why do we assume zero mean noise in sensor data?

I am reading a paper on measuring respiratory patterns from video data. In defining the model, the authors formulate the problem mathematically as: $x_i(t)=h_i(t) \ast g(t) + n_i(t) $ Where $n_i(t)...
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change convolution function if signal is above threshold?

Let's say I have a signal $s(t)$ and two filters $f_1(t)$ and $f_2(t)$, I also have a threshold $A$. Now I define $a_1(t)$ as $a_1(t) = \min(s(t),A)$, then I do the convolution of $a_1* f_1$. Now I ...
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Does anyone can help me with signal processing problem?

(c)A linear time-invariant system with impulse response $h(t)=e^{-\alpha t} u(t)$ is driven by the input $x(t)=e^{-\beta t} u(t)$ . It is assumed that $\alpha, \beta > 0$. (i) Using ...
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270 views

Proper way of representing Static, delta, delta delta in a plot

I am currently working on recreating the result of this paper. The paper is about applying cnn in speech recognition, in which cnn is used to for feature extraction, for which a proper way of ...
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3k views

conversion of 1d signal to 2d signal for CNN operation

I have a 1D signal data sampled at 25kHz and I want to modify in to 2D signal so as to modify it as the input to ConvolutionalNets as they work only on 2 dimensional data. What are possible ways to ...
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Fourier Transform of Kernel Density Estimation - Convolution Theorem?

I am reading this paper about density estimation (Appendix A), where the authors apply a Fourier transform to the estimated probability density (the $X_j$ are a sample of $N$ data points drawn ...
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FIR filter usage / understanding FIR

Let us assume that I wouldd like to create a digital lowpass with 5 taps. I am not using a window function but just the impulse response from my Fourier integral. I get the following coefficients: $h=...
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1answer
176 views

LTI filtering for wide-sense stationary process

Why is it that if $U[n]$ is wide-sense stationary and it is convolved with $h[n]$ to produce $W[n]$, the autocorrelation becomes $R_{WW}[n] = R_{UU}[n]*h[n]*h[-n]$? I know that in general $R_{WW}[n_{...
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A music recommender system by using basis functions

So my university project is about music recommender system. My teacher not saying too much. But he only said it will use basis functions and convolution technique. That's all i got from him. I want ...
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1answer
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How do I efficiently evaluate a convolution integral between different-sized domains?

This is a question that I've previously asked over on math.stackexchange, and I have yet to receive a useful answer. It was suggested that I post this here. The problem itself originally comes from ...
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Appropriate digital filter for GPS tracks?

I have an open-source software project whose purpose is to analyze a GPS track, or a similar track made by an application such as google maps, and estimate the physical exertion required to hike or ...
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277 views

Can I compute convolution through the overlap and add method without the IFFT?

So, I'm (I think) aware of how the overlap and add algorithm for linear convolution works, but my question is that, suppose I have a FFT-ed set of sequences that belong to a large sequence. Can I add ...
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316 views

the sub-range of circular and linear convolution

circular convolution $x_{_3p}[n]$ = $x_1[n]~\circledast_N ~x_2[n]$ is a period version of the linear convolution $x_{_3p}[n]=x_1[n] * x_2[n]$ The length of $x_1[n]$ and $x_2[n]$ are $L$ ($n\in[0,\...
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Locate first minima in signal

I have many datasets which all looks roughly like this: All the datasets have this in common. First there is an artifact around 0 with an unknown (but likely very high) intensity. Then there is some ...
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139 views

convolve to differentiate black and white colors

a figure for instance of size 500*500 has half above part with black and below half white should result in a white line where the white meets the black (something like a single line at line 250 with ...
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515 views

Can someone explain what a butterfly is in regards to DSP?

I often see the term "butterfly" in discussion and methods relating to DSP. What is a "Butterfly?"