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0answers
36 views

how to get an input test signal for convolution/ distortion method

i am trying to do some experiments with Total Harmonic Distortion. According to ...
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0answers
40 views

STFT on audio signal

I am trying to implement a STFT on audio signal as an exercise, and in order to do real-time filtering if I can get the "sound->STFT->inverseSTFT->reconstructed sound" chain to work. What I do for ...
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1answer
69 views

FFT Convolution: missing sample somewhere

For a piece of software I've been working on lately I need to implement FFT convolution for performance reasons. Doing so has been mildly succesfull but there is still a error somewhere causing lots ...
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0answers
24 views

Most efficient/sparsest piecewise linear approximation of signals

When standard linear regression is becomes unefficient, Piecewise Linear Regression Models are sometimes preferred over Polynomial Fits for tractable sigmal models. Indeed, they should be called ...
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0answers
51 views

Quantitative comparison of scaled-, delayed- and warped-signals

In several signal processing techniques, such as blind source separation (BSS) or deconvolution, one may wish to estimate a signal $x(t)$ and recovers $s.x(t+d)$, where $s$ is a scale factor, $d$ a ...
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1answer
118 views

Vinyl Crackling Effect

I want to know how can I achieve this effect: https://www.youtube.com/watch?v=DQg9M_47c3A Do I need to use a filter? And what can I use for the crackling, poping effect? Thanks in advance!
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1answer
87 views

Distances In a Single Image With Some Real References

Consider following image: We have some real references here: Stonehenge measurements (stone dimensions and distances), some strait lines at the back of carts, cart wheels that are almost of the ...
2
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2answers
97 views

How to estimate radial distortion from lens characteristics?

Is there a way to estimate the radial distortion coefficients without calibration, given the lens characteristics, such as its diameter and its focal length? Typically for camera calibration a ...
0
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1answer
83 views

Slight crackle with overlap-add frequency-domain convolution

I'm trying to make an FFT audio filter using overlap-add but there's some slight rhythmic distortion/crackle in the output. I have an irSize (impulse response size) of 512 samples and a blockSize of ...
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0answers
93 views

Can sample aliasing of strictly white noise lead to random walk (drift) in the sampled signal?

Aliasing of tones higher than the Nyquist frequency, and where the tone may have some degree of nonlinear distortion can appear as low frequency 'drift' or even near static bias in the sampled signal. ...
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2answers
35 views

What is done to minimize distortion due to the hold operation?

A hold operation can be modeled using a step function over one sampling period i.e. $R(t) = 1/T * (h(t) - h(t-T))$, $h(t)$ the step function In frequency domain this is equivalent to $R(jw) = ...
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1answer
147 views

Total Harmonic Distortion calculation and its origins

I ve been researching about harmonic distortion and THD. From what i ve seen on the internet, HD is caused by non-linear signal processing. I want to calculate it using an digital signal processor. ...
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1answer
152 views

FFT window corrupts signal

this is a newbie question. My goal is to create audio filter that cleans human speech from noise. I started with learning all about fft filters. At first I've created simple fft filter with ...
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0answers
109 views

Why does my overlap-add integrator in frequency domain result in distorted signals?

With help from the dsp guide and DSP-Related, I tried to implement a leaky integrator in octave/matlab. It seems to work in general, but there are a few problems. So that's what I do: Calculate the ...
2
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1answer
933 views

How to model Tape Saturation (Audio DSP)?

I'm looking for info that would help me to build a Tape Saturation process. I'm working with the WebAudio API. The API provides a number of DSP nodes that perform basic processes, such as a Convolver ...
2
votes
4answers
125 views

Camera Calibration using Single Input Image

Given a camera, permanently located at the same position, angle and distance from what is being captured, and a single calibration image ( a row of vertical lines [ | | | | ] ), how would one go about ...
1
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0answers
289 views

Motion and Distortion Estimation using multiple still images?

TL/DR: I'd like to take the median of lots of images to make a single "better" image. The problem is, the camera is slowly moving, and there is significant lens distortion. On the plus side the ...
4
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3answers
2k views

Digital Distortion effect algorithm

I read the DAFX book by Udo Zölzer about the distortion effect at pages 124-125 and it says that suitable simulation of the distortion is given by the function: ...
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3answers
324 views

importance of symmetric windows for STFT for practical applications

I am wondering why is the linear phase property of filters with symmetric coefficients important for some practical applications of short time fourier transform, such as image processing? I have read ...
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1answer
563 views

How to calculate Noise and distortion of an image?

I need to make an application in iphone which needs to calculate noise, geometric deformation other distortions in an image. How to do this? I have done some image processing stuff with opencv + ...
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2answers
4k views

Add odd/even harmonics to signal?

How do I add odd or even harmonics to a floating point signal? Do I have to use tanh or sin? What I'm trying to do is achieve some very simple distortion effects, but I'm having a hard time finding ...
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9answers
14k views

Algorithm(s) to mix audio signals without clipping

I'd like to mix two or more PCM audio channels (eg recorded samples) digitally in an acoustically-faithful manner, preferably in near-real-time (meaning little or no peek-ahead). The physically ...
9
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4answers
821 views

Is there such a thing as band-limited non-linear distortion?

So if you generate a square wave by just switching a signal between two values, at sample boundaries, it produces an infinite series of harmonics, which alias and produce tones below your fundamental, ...