Signal Processing Stack Exchange
Signal Processing Stack Exchange

Most Popular

more tags
1500 questions
7
votes
2 answers

Sequentially get the outer contour of an Edge Image

Hi CV/Pattern Recognition Community, because my last thread was concerning the segmentation as BLOB and started to getting too big, with no clear results. I would like to reconcider the last step of that process regarding the sequential gaining of…
mchlfchr
  • 587
  • 1
  • 6
  • 17
7
votes
6 answers

Why can't a causal digital filter have an infinitely sharp transition between the passband and the stopband?

In DSP book by Proakis and as well as in this pdf, it is mentioned that practical causal digital filters cannot have an infinitely sharp transition from Pass-band to Stop-band. Why is it so? Can you please provide a detailed explanation (with…
Nagabhushan S N
  • 447
  • 4
  • 18
7
votes
2 answers

Hilbert transform of sinusoid -- apparent contradiction

The arrow "$\xrightarrow{\mathcal H}$" denotes a Hilbert transform: $$\cos(\omega t)\xrightarrow{\mathcal H} \sin(\omega t)$$ happiness. But $$\cos(\omega t) = \cos(-\omega t) \xrightarrow{\mathcal H} \sin(-\omega t) = -\sin(\omega…
user3856370
  • 173
  • 5
7
votes
2 answers

Difference between $\mathbb{E}[\mathbf{x} \mathbf{x}^{\rm{H}}]$ and $\mathbb{E}[(\mathbf{x}-\boldsymbol{\mu}) (\mathbf{x}-\boldsymbol{\mu})^{\rm{H}}]$

Let us have a random vector $\mathbf{x} \sim \mathcal{CN} (\boldsymbol{\mu}, \boldsymbol{\Sigma})$ with $\boldsymbol{\mu} \neq \mathbf{0}$. What can we say about the relationship between the elements of $\mathbf{x}$ in the following two separate…
TheDon
  • 171
  • 3
7
votes
3 answers

How to correctly compute the EEG Frequency Bands with Python?

so I am trying to compute the EEG(25 channels, 512 sampling rate, 248832/channel) bands (alpha, beta, gamma, etc.) with Python. I managed to do so by: firstly filtering the signal with a butterworth filter that looks like this: def…
user3640476
  • 113
  • 1
  • 2
  • 6
7
votes
5 answers

Why Does the Kalman Filter Remove Only Gaussian Noise?

What and where in the derivation of the Kalman filter is the assumption of Gaussian noise? Why and how does this assumption help?
IG123
  • 71
  • 1
  • 3
7
votes
4 answers

MMSE Estimation - Fusion of 2 Measurements

Let's say I have 2 measurements of the same phenomenon (for example current temperature) and I want to find the MMSE (minimum mean square error) estimator, i.e to minimize the MSE (mean square error). The measurements are independent and the noise…
Nir
  • 79
  • 1
7
votes
1 answer

Compute SQNR (Signal to Quantization Noise Ratio)

I'm studying the quantization of an audio signal and in particular the SQNR (Signal to Quantization Noise Ratio). The book on which the study says that: where: N is the number of bits in the digital representation V indicates that the signal…
sleepwalking
  • 229
  • 2
  • 4
  • 11
7
votes
5 answers

Effects of linear interpolation of a time series on its frequency spectrum

Situation In order to synchonisize different time series i have to apply linear interpolation on them. After the interpolation and synchronization the signal is transferred into its frequency domain for further analysis. The interpolation step…
Dominik K.
  • 93
  • 1
  • 4
7
votes
2 answers

Why is the median filter called 'edge-preserving'?

I want to know about median filtering. Recently, I read that it is best for preserving edges. But how does it preserve edges? I need complete knowledge of median filters. Why it is non-linear filter and why it is best, compared to linear filter?
sufi
  • 71
  • 1
  • 3
7
votes
4 answers

Palm Pilot Graffiti

I have been completely unable to find details on the underlying model that is used for the Palm Pilot Graffiti handwriting recognition. Given the computing power available for handheld PDA technology, I have always been quite surprised this was…
adfriedman
  • 173
  • 3
7
votes
2 answers

Difference between RMS and a moving RMS

I don't quite get the difference between RMS and a moving RMS. When one calculates RMS, one integrates (or sums in case of a discrete signal) over a period of time(number of samples). When it comes to a moving RMS, I don't quite get the idea why…
chsafouane
  • 313
  • 1
  • 4
  • 8
7
votes
5 answers

What Is the Transfer Function of a Moving Average (FIR Filter)?

To make post-processing easier, I export scope measurements as CSV files, which are then post-processed (mostly in Microsoft Excel, which is not the best tool for the job, but it is all I have at my disposal). One of the post processing used is a…
Sclrx
  • 271
  • 1
  • 3
  • 6
7
votes
3 answers

Random signals as power signals

Why are random signals considered as power signals (i.e. signals with infinite energy and finite average power)? Does this make any sense? What does it mean for random signals to have infinite energy even though we know that real-life signals…
Likely
  • 153
  • 1
  • 9
7
votes
1 answer

Filter design to realize Cauchy product

I come from Computer Science so please pardon for my possibly wrong terminology. I need to design a filter which has coefficients $$h_0, h_1, \ldots, h_n, \ldots \quad\text{such that}\quad h_0 > h_1> \ldots > h_n > \ldots$$ The input is $x_n$. The…
Ngoc Anh Huynh
  • 81
  • 2
1 2 3
…
99 100