Signal Processing Stack Exchange
Signal Processing Stack Exchange

Most Popular

more tags
1500 questions
8
votes
3 answers

How is a human whistle a pure sine wave?

According to Wikipedia human whistling is a pure sine wave. If that is true and if a human is whistling and produces a rhythm like any song, is he still producing a pure sine wave? For example, if I am producing a tone of any music through my…
Sufiyan Ghori
  • 2,175
  • 11
  • 34
  • 50
8
votes
1 answer

What are the state of the art methods for person segmentation and person pose identification

I know that HOG is pretty state of the art for person detection, but in its original form HOG is only a detection method, and I don't believe it is particularly fast either (there is a significant speedup which takes the sliding window and rejects…
John Robertson
  • 1,122
  • 1
  • 9
  • 13
8
votes
2 answers

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
  • 1,968
  • 2
  • 22
  • 29
8
votes
2 answers

Is there an equivalent of Parseval's theorem for wavelets?

Parseval's theorem can be interpreted as: ... the total energy of a signal can be calculated by summing power-per-sample across time or spectral power across frequency. For the case of a signal $x(t)$ and its Fourier transform $X(\omega)$, the…
hazrmard
  • 225
  • 3
  • 9
8
votes
4 answers

Is the first derivative operation on a signal a causal system?

Please help me sort this issue out. Consider a system whose output $y(t)$ is the first derivative of the input signal $x(t)$. We can write the first derivative of an input signal as follows: $$y(t)=\frac{dx(t)}{dt}=\lim_{\Delta t\to…
Jarvis1997
  • 171
  • 1
  • 11
8
votes
1 answer

2-d circularly symmetric low-pass filter

For a square pixel grid, the ideal 2-d low-pass filter with a horizontal and a vertical cut-off angular frequency $\omega_c$ in radians has an impulse response (kernel) $h_{\small\square}(x, y)$ that is the product of a horizontal and a vertical…
Olli Niemitalo
  • 13,491
  • 1
  • 33
  • 61
8
votes
5 answers

Multi-channel audio upsampling interpolation

I have a four-channel audio signal from a microphone tetrahedral array. I wish to upsample it from 48 kHz to 240 kHz. Is there a preferred interpolation method for audio? Does cubic interpolation (or any other) have any advantages over linear for…
havakok
  • 672
  • 1
  • 5
  • 19
8
votes
1 answer

Optimal amplitude of an $m$-bit sinusoid

A continuous-time sinusoid of zero-to-peak real amplitude $A \le 2^{m-1}-0.5$ (e.g., for $m=16$, $A \le 32767.5$) is quantized to $m$-bit resolution by rounding it to the nearest integer (Fig. 1). What is the optimal amplitude for different $m \le…
Olli Niemitalo
  • 13,491
  • 1
  • 33
  • 61
8
votes
2 answers

What Does 'Zero Order Hold' and 'First Order Hold' Mean?

While studying the Image Magnification in spatial domain, I have come across this definition of Image Magnification by Replication: Replication is a zero order hold where each pixel along a scan line is repeated once and then each scan line is…
bikalpa
  • 211
  • 1
  • 2
  • 9
8
votes
3 answers

Protect an IIR filter from being reverse-engineered

I created a somewhat unique IIR filter and I want to protect the filter from being reverse-engineered I think you all know it is quite easy to get all the different weights of an IIR by using impulse signals. The filter is programatically…
Jeff
  • 89
  • 5
8
votes
5 answers

Estimators for improved spectral subtraction of noise

Real zero-mean Gaussian white noise, independent of a clean signal $x$ and of known variance is added to $x$ producing a noisy signal $y.$ Discrete Fourier transform (DFT) $Y$ of the noisy signal is calculated by: $$Y_k =…
Olli Niemitalo
  • 13,491
  • 1
  • 33
  • 61
8
votes
1 answer

Comparing multiple signals for similarity

I have multiple (between 2 and 100) signals and need to determine when a significant number diverge from the rest. We're exploring machine learning techniques, but we also want tackle this as a signal processing problem and see where we get the best…
John Strong
  • 201
  • 2
  • 4
8
votes
1 answer

What is different between Euclidean distance and the Geodesic distance?

We have two kinds of distance in image: Euclidean distance and the Geodesic distance. What is different between them? Could you show mathematic formula or visualization to make it clear? The reference said Difference between the Euclidean distance…
Moon Lee
  • 191
  • 1
  • 3
8
votes
1 answer

Proving Nyquist Sampling Theorem for Strictly Band Limited Signals (Whittaker Shannon Interpolation Formula)

I understand that the Nyquist sampling theorem dictates that the minimum sampling frequency, $f_s$, be s.t. $f_s > 2B$, where $ B $, is the bandwidth of the signal. I have read the explanation for what happens when the input signal contains an…
RJ_DSP
  • 81
  • 2
8
votes
2 answers

Using the Inverse Filter to Correct a Spatially Convolved Image (Deconvolution)

As part of a homework assignment, we are implementing the Inverse Filter. Degrade an image then recover with an Inverse Filter. I convolve the image in the spatial domain with a 5x5 box filter. I FFT the filter, FFT the degraded image, then divide…
David Poole
  • 298
  • 3
  • 8
1 2 3
…
99 100