Signal Processing Stack Exchange
Signal Processing Stack Exchange

Questions tagged [software-implementation]

Questions related to implementation of various algorithms under software environments and programming languages.

Questions related to design, implementation and numerical optimization of various algorithms including audio, image processing, filtering, computer vision, statistics.

82 questions
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What does one need to know in order to build a software synthesizer?

For someone who has some experience in software development, loves his synths and knows the [very] basics of digital audio representation, what are the first steps he should follow in order to program a music synthesizer, DSP-wise?
deprecated
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How to implement a digital oscillator?

I have a floating-point digital signal processing system that operates at a fixed sample rate of $f_s = 32768$ samples per second implemented using an x86-64 processor. Assuming that the DSP system is synchronously locked to whatever matters, what…
nibot
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Where can I get an open source implementation of the Parks-McClellan optimal FIR filter design algorithm?

Background: Often times I am doing some sort of signal processing task that requires a unique filter. Usually at this point I go to MATLAB and generate a new unique filter using $\tt firpm()$. The MATLAB firpm() function implements that…
Trevor Boyd Smith
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Are there any standard implementation forms for tunable Butterworth filters?

One of the standard ways to implement a Butterworth filter is with a cascade of second-order sections, each corresponding to a pair of complex-conjugate poles. For a fourth-order filter, for example, there would be two second-order sections. If we…
datageist
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Removing Glare from Image

Disclaimer: I am in NO way engaged in signal processing. Just very curious... Ny question is, very simply: is it possible to apply software processing to an image to remove or reduce headlight glare? It would be a picture such as this: If this…
BenCole
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System identification packages

I've been hunting around for an alternative to Matlab's System Identification Toolbox, but the commonality of the terms "system" and "identification" are confounding the search. Are there any standalone libraries that are written for this purpose?…
jonsca
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15
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When to consider double (64 bit) floating point for Audio

When synthesizing and processing audio on modern processors, when would one consider using something other than single precision (32 bit) floating point? Obviously, the audio coming in and going out to the real world is 16/24 bit, so I'm just…
user1849104
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Help with equations for exponential ADSR envelope

With application code, I have implemented a linear ADSR envelope for shaping the amplitude of an oscillator's output. The parameters for attack, decay and release duration as well as sustain level can be set on the envelope and everything works as…
Gary DeReese
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3 answers

"Low-pass filter" in non-EE, software API contexts

I am an experienced software engineer and am working on smartphone sensors. I've taken fundamental EE classes in DSP and am trying to apply my knowledge. I believe that I understand convolution, transfer functions, z-transform, etc. I know a little…
stackoverflowuser2010
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How does MATLAB handle IIR filters?

MATLAB has a butter, which constructs a Butterworth filter given an order and relative cutoff frequency. The filter created can be used to filter any finite signal. How does MATLAB do this if the filter has an infinite impulse response? I suppose it…
Andreas
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Help with algorithm for modulating oscillator pitch using LFO

I am developing a software emulation of an analog synthesizer. I am trying to modulate the pitch of an oscillator using an LFO. For each sample fed to the computer's sound system, I am calculating the frequency to be input into the main oscillator…
Gary DeReese
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Which Noise Reduction Algorithms Are Used in Commercial RAW Image Processors?

I'm trying to guess what noise reduction algorithms are used in commercial processors for raw images from digital cameras. I find this fairly easy to do for the sharpening algorithms (most use unsharp mask as at least one option, for example, and…
Potato
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Convolution involving turning each pixel value to the most represented pixel value of the neighbourhood

In order to correct gradual changes of intensities in the background of grey-scales images, I have been blurring them and then subtracting the original images from the convolved one. In some cases, I have seen improvement using median blur instead…
Quentin Geissmann
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How to test digital filters?

First the question(s): How should I write unit tests for a digital filter (band-pass/band-stop) in software? What should I be testing? Is there any sort of canonical test suite for filtering? How to select test inputs, generate expected outputs,…
heltonbiker
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How do I apply a Chebishev filter?

I read a paper about a brain-computer interface. In this paper the authors reported "each signal has been filtered with an 8-order band-pass Chebishev Type I filter which cut-off frequencies are 0.1 and 10 Hz and has been decimated according to the…
alfa
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