Signal Processing Stack Exchange
Signal Processing Stack Exchange

Most Popular

more tags
1500 questions
8
votes
1 answer

Do FFT-based filtering methods add intrinsic latency to a real time algorithm?

In a current audio processing application, I am working entirely in the time domain using IIR filters. This is so I can use an audio buffer of just 3 or 4 samples and can guarantee that there will be some form of audio output within that frame. If…
learnvst
  • 1,513
  • 2
  • 17
  • 25
8
votes
6 answers

Why Carrier signal can't have frequency less than Message signal

I know that why we use Carrier of high frequency to send message signal over a long distance, when the frequency is low , energy will be obviously low. To increase the energy of the signal we need to increase the frequency. This is achieved by…
Sufiyan Ghori
  • 2,175
  • 11
  • 34
  • 50
8
votes
1 answer

Does our brain constantly ifft to hear?

From my understanding our ears have hairs/cilia in the cochlea that resonate at frequencies within our hearing range. To me this means we are hearing in the frequency domain as opposed to the time domain. But does that mean we are constantly…
benathon
  • 201
  • 1
  • 6
8
votes
1 answer

Restricted Isometry Property (RIP) in Compressive Sensing

What is the meaning of Restricted Isometry Property (RIP) condition in Compressive Sensing for Sparse Signal Analysis? How can we define Restricted Isometry Constant (RIC) for the RIP condition? Thanks in Advance!
tuner
  • 635
  • 1
  • 9
  • 17
8
votes
2 answers

Otsu binarization with value preservation

I'm trying to implement a modified version of the otsu binarization algorithm. I'm trying to binarize document images. But in the binarization procedure I want the object (in this case the text) to retain its original grayscale value while the…
mark
  • 475
  • 1
  • 7
  • 6
8
votes
1 answer

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
  • 311
  • 1
  • 2
  • 5
8
votes
5 answers

Detect dog barks

I’d like to use my Raspberry Pi to record when and how often my dog barks. But for privacy reasons, I don’t simply want to record the loudness in the room, so I have to automatically detect barks. How would I do that?
Joachim Breitner
  • 191
  • 1
  • 1
  • 5
8
votes
3 answers

FFmpeg audio filter pipeline for speech enhancement

Using ffmpeg, I'm recording a talk, its audio with a semi-distant microphone. It makes sense to somewhat enhance the speech clarity, reduce background static and environmental noise, etc., in the most generic terms. What combination of ffmpeg audio…
K3---rnc
  • 181
  • 1
  • 1
  • 5
8
votes
4 answers

How to: pixel packs in an image to representative point coordinates (x,y)

Let's have an image (gray-scale or even binary) as shown on the following figure at the left hand side, the goal is to generate a list of points i.e., coordinates in the form of (x,y) for each pack of the dark pixels in the image. What are the…
Developer
  • 1,129
  • 1
  • 10
  • 15
8
votes
3 answers

How to generalise the Fourier transform?

The Fourier transform takes a signal and splits it into a series of sine and cosine waves. I am told that it's supposed to be possible to split a signal into some other set of functions. My question is: How do you do this? I'm presuming that the set…
MathematicalOrchid
  • 263
  • 2
  • 5
8
votes
5 answers

Difference between DC component and zero frequency component of signal

We know that Fourier Transform of a signal exists if it is absolutely integrable and it exists for periodic signals if impulse functions are allowed. If we consider the fourier transform of $\text{rect}(t)$ , we get $\text{sinc}(f)$ in frequency…
spectre
  • 565
  • 1
  • 8
  • 15
8
votes
3 answers

FFT on non-rectangular part of image

I need to do a FFT on an image for noise reduction, but the problem is that I do not need the complete image, but only a circle in the middle. The borders are a fixed rig, thus I am not interested in what it displays, but it has an impact on the…
SinisterMJ
  • 257
  • 2
  • 5
8
votes
1 answer

Why does a wave continuously decreasing in frequency start increasing its frequency past the half of its length?

I'm trying to programmatically generate a wave (sine or square) with a continuously decreasing frequency. To do so, I simply multiply the starting frequency for a decreasing value, that linearly goes from 1 to 0, at intermediate steps throughout a…
rotor
  • 83
  • 3
8
votes
2 answers

How to define SNR for multiple signals in noise?

I have to estimate the number of signals present in a measurement contaminated by additive noise given $n$-dimensional snapshot vectors $\bf x$, modeled as $ \bf x = \bf A \bf s + \bf z $ where $\bf s$ is a $k \times 1$ vector representing $k$…
sauravrt
  • 416
  • 1
  • 3
  • 8
8
votes
2 answers

Why are there so many windowing functions?

Many windowing functions are listed here in the Mathematica documentation. I tried using a few to reduce leakage when computing a Discrete Fourier Transform. From what I could tell it made little difference which windowing function is used. Two of…
Ted Ersek
  • 509
  • 4
  • 11
1 2 3
…
99 100