# Signal and Image Processing

**URL:** https://discourse.julialang.org/c/domain/dsp/26.md?page=5

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**Page:** 6

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## [Record from an online audio stream](https://discourse.julialang.org/t/record-from-an-online-audio-stream/37385)

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**Author:** [@Martijn-R](https://discourse.julialang.org/u/Martijn-R)\
**Replies:** 7\
**Last updated:** [April 14, 2020, 11:09pm UTC](https://discourse.julialang.org/t/record-from-an-online-audio-stream/37385 "2020-04-14T23:09:18Z")

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I would like to record a few seconds of audio from an online .mp3 or .aac stream, for example from http://ais.absoluteradio.co.uk/absoluteclassicrock.mp3. I tried several ways: from within a terminal window, with R and …

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## [DSP.jl Resampled signal length doesn't match upsampling factor](https://discourse.julialang.org/t/dsp-jl-resampled-signal-length-doesnt-match-upsampling-factor/36036)

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**Author:** [@meritwagner](https://discourse.julialang.org/u/meritwagner)\
**Replies:** 3\
**Last updated:** [March 17, 2020, 4:50pm UTC](https://discourse.julialang.org/t/dsp-jl-resampled-signal-length-doesnt-match-upsampling-factor/36036 "2020-03-17T16:50:31Z")

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Hey guys, I ran into a problem, while trying out the resampling algorithm from the DSP package (v0.6.3). First I just create a test array with random numbers between 1 and 2. My plan is then to resample up by factor of…

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## [Keep filter state for frame-wise processing](https://discourse.julialang.org/t/keep-filter-state-for-frame-wise-processing/34867)

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**Author:** [@hagi](https://discourse.julialang.org/u/hagi)\
**Replies:** 4\
**Last updated:** [February 26, 2020, 8:53am UTC](https://discourse.julialang.org/t/keep-filter-state-for-frame-wise-processing/34867 "2020-02-26T08:53:46Z")

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When I want to do frame-wise filtering of a longer signal, I want to use the last filter states for processing the next frame. While it is clear how to pass the argument, I don’t get how the states are returned. If I u…

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## [Filtfilt in DSP.jl - I really don't get it](https://discourse.julialang.org/t/filtfilt-in-dsp-jl-i-really-dont-get-it/10437)

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**Author:** [@ceysa75](https://discourse.julialang.org/u/ceysa75)\
**Replies:** 3\
**Last updated:** [February 17, 2020, 11:21pm UTC](https://discourse.julialang.org/t/filtfilt-in-dsp-jl-i-really-dont-get-it/10437 "2020-02-17T23:21:49Z")

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Hi dear community members, while making bigger steps forwards switching completely from Matlab to Julia here and there I am often struggling to solve some issues. This is mainly due to the poor/missing documentation of…

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## [IFFT Scaling](https://discourse.julialang.org/t/ifft-scaling/33979)

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**Author:** [@jleman](https://discourse.julialang.org/u/jleman)\
**Replies:** 5\
**Last updated:** [January 30, 2020, 9:25pm UTC](https://discourse.julialang.org/t/ifft-scaling/33979 "2020-01-30T21:25:38Z")

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Does anyone know if there is a 1/N or 1/sqrt(N) scaling in the IFFT function of FFTW.jl? I am taking the IFFT of an array of complex numbers sampled from a continuous frequency domain function. The resulting time domai…

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## [Is there any package for Lomb Scagle?](https://discourse.julialang.org/t/is-there-any-package-for-lomb-scagle/28850)

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**Author:** [@yw892](https://discourse.julialang.org/u/yw892)\
**Replies:** 5\
**Last updated:** [September 29, 2019, 12:55pm UTC](https://discourse.julialang.org/t/is-there-any-package-for-lomb-scagle/28850 "2019-09-29T12:55:30Z")

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Just wondering. It seems Julia doesn’t support many DSP algorithms like EMD and Lomb Scagle.

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## [FM demodulation](https://discourse.julialang.org/t/fm-demodulation/27604)

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**Author:** [@Alexander-Barth](https://discourse.julialang.org/u/Alexander-Barth)\
**Replies:** 5\
**Last updated:** [September 8, 2019, 6:53pm UTC](https://discourse.julialang.org/t/fm-demodulation/27604 "2019-09-08T18:53:10Z")

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Does Julia have a FM demodulation function? My plan is to process data from a software-defined radio (SDR). Would it be a suitable contribution for the DSP.jl package, if such a function does not jet exists for julia?

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## [\[DSP.jl\] What resampling parameters should I use to get the same output as the decimate function in MATLAB?](https://discourse.julialang.org/t/dsp-jl-what-resampling-parameters-should-i-use-to-get-the-same-output-as-the-decimate-function-in-matlab/28357)

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**Author:** [@Losses](https://discourse.julialang.org/u/Losses)\
**Replies:** 4\
**Last updated:** [September 6, 2019, 10:58am UTC](https://discourse.julialang.org/t/dsp-jl-what-resampling-parameters-should-i-use-to-get-the-same-output-as-the-decimate-function-in-matlab/28357 "2019-09-06T10:58:16Z")

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Hello everyone, I am a cognitive neuroscience researcher, have little knowledge about the detail of signal processing, We are trying to resampling our signal with DSP.jl, and expect to get identical(or similar) result as…

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## [How to see the output from DSP.Periodograms.periodogram?](https://discourse.julialang.org/t/how-to-see-the-output-from-dsp-periodograms-periodogram/26732)

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**Author:** [@Andrzej\_Ceglowski](https://discourse.julialang.org/u/Andrzej_Ceglowski)\
**Replies:** 2\
**Last updated:** [August 6, 2019, 2:26am UTC](https://discourse.julialang.org/t/how-to-see-the-output-from-dsp-periodograms-periodogram/26732 "2019-08-06T02:26:23Z")

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Thank you for taking the time to look at my rookie problem. I cannot find documentation on the periodogram type variable and consequently cannot access the results of DSP periodograms routine. Can you help? The steps/d…

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## [Waveform Characterization](https://discourse.julialang.org/t/waveform-characterization/20654)

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**Author:** [@bomber8013](https://discourse.julialang.org/u/bomber8013)\
**Replies:** 3\
**Last updated:** [July 25, 2019, 10:45pm UTC](https://discourse.julialang.org/t/waveform-characterization/20654 "2019-07-25T22:45:57Z")

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I am developing a library for basic waveform characterization. Linked WaveformAnalysis.jl I have a few of the functions done pretty well done in the most efficient way I can think of. I am getting hung up right now with…

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## [I succeeded to porting the POC with Julia.](https://discourse.julialang.org/t/i-succeeded-to-porting-the-poc-with-julia/22488)

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**Author:** [@bemorejul](https://discourse.julialang.org/u/bemorejul)\
**Replies:** 0\
**Last updated:** [March 29, 2019, 3:18am UTC](https://discourse.julialang.org/t/i-succeeded-to-porting-the-poc-with-julia/22488 "2019-03-29T03:18:09Z")

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I succeeded to porting the POC(Phase only correlation) with Julia.

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## [I succeeded to Spectral Saliency Map. But ...](https://discourse.julialang.org/t/i-succeeded-to-spectral-saliency-map-but/22458)

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**Author:** [@bemorejul](https://discourse.julialang.org/u/bemorejul)\
**Replies:** 0\
**Last updated:** [March 28, 2019, 1:33pm UTC](https://discourse.julialang.org/t/i-succeeded-to-spectral-saliency-map-but/22458 "2019-03-28T13:33:49Z")

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Hi, all. I succeeded to making Spectral Saliency Map. But … The result map is flipped to vertically. Why this happen? Julia’s FFT function is different from matlab? I wonder …

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## [Error in FFT?](https://discourse.julialang.org/t/error-in-fft/19310)

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**Author:** [@LewisHein](https://discourse.julialang.org/u/LewisHein)\
**Replies:** 5\
**Last updated:** [January 7, 2019, 2:25pm UTC](https://discourse.julialang.org/t/error-in-fft/19310 "2019-01-07T14:25:04Z")

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Brief problem here, I will try to add graphs later. I can create a function that returns a gaussian, discretize it, and take the FFT with fft() or rfft() from the FFTW module. This does not return a gaussian as it should…

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## [Wrapping function chains in a type](https://discourse.julialang.org/t/wrapping-function-chains-in-a-type/14586)

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**Author:** [@RainerHeintzmann](https://discourse.julialang.org/u/RainerHeintzmann)\
**Replies:** 0\
**Last updated:** [September 5, 2018, 3:59pm UTC](https://discourse.julialang.org/t/wrapping-function-chains-in-a-type/14586 "2018-09-05T15:59:41Z")

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I am having difficulties to understand how to best avoid local memory allocation. Here is some code based on CartesianIndices, which works really fast and nicely as it is NOT allocating extra memory: using LinearAlgebra…

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## [How does Julia compare to J and other APL languages? ](https://discourse.julialang.org/t/how-does-julia-compare-to-j-and-other-apl-languages/10854)

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**Author:** [@\_richard](https://discourse.julialang.org/u/_richard)\
**Replies:** 0\
**Last updated:** [May 12, 2018, 9:28am UTC](https://discourse.julialang.org/t/how-does-julia-compare-to-j-and-other-apl-languages/10854 "2018-05-12T09:28:11Z")

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If speed is the primary consideration, is Julia faster? How does Julia deal with threading? I’m asking as a former SequenceL user. Thanks for any feedback!

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## [Determine instantaneous frequency (IF) with Julia](https://discourse.julialang.org/t/determine-instantaneous-frequency-if-with-julia/5529)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 5\
**Last updated:** [April 18, 2018, 1:15am UTC](https://discourse.julialang.org/t/determine-instantaneous-frequency-if-with-julia/5529 "2018-04-18T01:15:25Z")

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Hello, I am looking for a way to determine the instantaneous frequency of a signal (filtered BDLC motor phase voltage) to determine the speed of this motor. The sampling frequency is 8 kHz, the max, electrical frequenc…

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## [Looking for guidance - signal processing team](https://discourse.julialang.org/t/looking-for-guidance-signal-processing-team/9855)

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**Author:** [@sirtom67](https://discourse.julialang.org/u/sirtom67)\
**Replies:** 1\
**Last updated:** [March 21, 2018, 11:44am UTC](https://discourse.julialang.org/t/looking-for-guidance-signal-processing-team/9855 "2018-03-21T11:44:58Z")

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Anyone interested in helping contribute to the DSP.jl project? I could use some help and guidance on how to contribute. The “esprit” function that I added this week finds the frequencies of sinusoidal signals: https://…

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## [Should there be an inverse stft in DSP.jl?](https://discourse.julialang.org/t/should-there-be-an-inverse-stft-in-dsp-jl/6661)

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**Author:** [@standarddeviant](https://discourse.julialang.org/u/standarddeviant)\
**Replies:** 1\
**Last updated:** [October 24, 2017, 6:39pm UTC](https://discourse.julialang.org/t/should-there-be-an-inverse-stft-in-dsp-jl/6661 "2017-10-24T18:39:22Z")

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I’ve seen a few implementations in matlab, but this describes things the stft / istft procedure at a higher-level: I’m interested in this and am wondering if other people would be interested in this.

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## [ANN: Julia bindings for ensemble empirical mode decomp](https://discourse.julialang.org/t/ann-julia-bindings-for-ensemble-empirical-mode-decomp/886)

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**Author:** [@merl-dev](https://discourse.julialang.org/u/merl-dev)\
**Replies:** 2\
**Last updated:** [September 29, 2017, 7:09pm UTC](https://discourse.julialang.org/t/ann-julia-bindings-for-ensemble-empirical-mode-decomp/886 "2017-09-29T19:09:59Z")

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I’ll be doing some work over the next few months that makes use of an interesting approach to signal processing developed in the late 90s called the empirical mode decomposition. Used primarily in the analysis of nonlin…

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## [How to identify local maxima (peaks) in a time signal?](https://discourse.julialang.org/t/how-to-identify-local-maxima-peaks-in-a-time-signal/6000)

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**Author:** [@ceysa75](https://discourse.julialang.org/u/ceysa75)\
**Replies:** 5\
**Last updated:** [September 22, 2017, 2:20pm UTC](https://discourse.julialang.org/t/how-to-identify-local-maxima-peaks-in-a-time-signal/6000 "2017-09-22T14:20:10Z")

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Hi folks, making my first steps in Julia with the basic aim to finally get rid of Matlab. I am searching for a package which helps me identiying local extremes, i.e. peak values, from a monitored time signal (decaying v…

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## [Packages for signal decomposition](https://discourse.julialang.org/t/packages-for-signal-decomposition/5909)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 4\
**Last updated:** [September 15, 2017, 8:52pm UTC](https://discourse.julialang.org/t/packages-for-signal-decomposition/5909 "2017-09-15T20:52:19Z")

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What are the packages out there for decomposing a signal into a basis of functions? Fourier basis, Radial basis, Cosine basis, … I need to decompose a signal into a set of basis functions and coefficients, manipulate th…

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## [State of DSP?](https://discourse.julialang.org/t/state-of-dsp/1559)

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**Author:** [@purplishrock](https://discourse.julialang.org/u/purplishrock)\
**Replies:** 22\
**Last updated:** [August 1, 2017, 4:10pm UTC](https://discourse.julialang.org/t/state-of-dsp/1559 "2017-08-01T16:10:54Z")

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looks like it might be in need of some help the examples could be improved. it’s not currently running any tests for 0.5 i’m volunteering :slight\_smile:

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## [Adding Shearlet transform package to JuliaDSP](https://discourse.julialang.org/t/adding-shearlet-transform-package-to-juliadsp/2498)

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**Author:** [@arsenal9971](https://discourse.julialang.org/u/arsenal9971)\
**Replies:** 2\
**Last updated:** [March 8, 2017, 10:59am UTC](https://discourse.julialang.org/t/adding-shearlet-transform-package-to-juliadsp/2498 "2017-03-08T10:59:11Z")

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Dear Julians and hopefully members of JuliaDSP organization, My name is Héctor Andrade Loarca and I am currently doing my PhD in mathematics specialized in Digital Signal Processing and Compressed Sensing, specially in …

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