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4 votes

Signal and Space/Time

You probably have a small misunderstanding here. In the definition it is not said "time" and "space" but "time" or "space". Some signals vary with time, as your ...
MimSaad's user avatar
  • 1,976
4 votes
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What's the point of differential beamforming?

Introduction To my (rather limited) knowledge, the main advantage that made Differential Microphone Arrays (DMA) popular is their ability to have a frequency invariant beampattern (up to some certain ...
ZaellixA's user avatar
  • 1,314
3 votes

Finding the equivalent filter H(u,v) in the frequency domain of a 3x3 spatial mask

Hint: $g(x,y)$ averages all pixel values around $f(x,y)$, at 8-neighbour connectivity distance 1, except $g(x,y)$. The classical uniform $3\times 3$ average is: $$ m(x,y) = \frac{1}{9}\sum_{i\in[-1,...
Laurent Duval's user avatar
3 votes
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What does PSD represent in the spatial domain?

Please see this response. Radiant Flux should take care of the physical units. The PSD in the spatial domain would represent a "dominant" blob, whose shape is determined by the spectral content of ...
A_A's user avatar
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2 votes
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2D Spatial Fourier Tranform on a pressure field

Time domain representation As Max have presented in their answer, acoustic pressure variations in two dimensions, that you are interested in, is given as a function of time $t$ and spatial (Cartesian ...
ZaellixA's user avatar
  • 1,314
1 vote

Confusion sampling rate of a spatial array

For an input signal with "domain" unit, $u$, the units of the Fourier Transform's domain are periods per $u$ or cyles per $u$. For a time-series signal with domain "seconds," the ...
Ash's user avatar
  • 915
1 vote

How to reconstruct image from an Under Sampled MRI k-space data?

I was experiencing a similar problem (CS reco looked the same as the simple FT reco). What helped me was to normalize my data to max=1, ...
luca's user avatar
  • 11
1 vote
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Spatial sampling frequency equation

The spatial sampling frequency of a linear array with equidistant sensor (antenna) spacing on the $x$-axis is simply given by $$f_x=\frac{1}{d}\tag{1}$$ where $d$ is the distance between the sensors ...
Matt L.'s user avatar
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1 vote

What is the meaning of spectral contamination in image processing?

"Spectral contamination" is used for designating a few phenomena connected with spectral analysis in optics, acoustics, analytical chemistry. I have never heard of these words to be used in ...
V.V.T's user avatar
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1 vote
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How to detect the presence one- and two-dimensional patterns in distributions of spatial points?

Perhaps you could perform blob detection to find the individual dots and then map their location to a 2d space, that preserves their spatial structure, through the use of some measure for example the ...
kalgoritmi's user avatar
1 vote
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HRIR interpolation using VBAP

For your known bug: Since your azimuth-elevation grid is uniformly distributed, finding the closest triangle containing the target direction is not difficult. Say the target direction is $(\varphi, \...
ZR Han's user avatar
  • 3,248
1 vote

HRIR interpolation using VBAP

This is a long post with a lot of info, I just and give some high level feedback Loose the 1.47 scale factor and just do everything on the unit sphere. If absolute distance/gain matters, just scale ...
Hilmar's user avatar
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1 vote

Are there standards/references for determining spatial scale in photographic images?

One possible answer to my own question is provided by the photographic scale reference detailed on this website. https://smallpond.ca/jim/scale/ It doesn't quite provide the solution I was looking ...
mattroos's user avatar
1 vote

Calculating spatial width from power spectrum HWHM

Say I have a 1D (spatial) signal (resolution = $1000$) which is zero everywhere except from $x=250$ to $750$, where it equals one. This is not "resolution". Resolution is 300 Dots Per Inch. In which ...
A_A's user avatar
  • 10.7k
1 vote

Simulating spatial perception - with cosine wave based sound - in MATLAB

Nothing is wrong, apart from assuming that the delayed $\cos$ extends to infinity both towards negative and positive time. In other words, the delayed version of the cosine starts 2msec after the non-...
A_A's user avatar
  • 10.7k
1 vote

Simulating spatial perception - with cosine wave based sound - in MATLAB

Try this ...
Hilmar's user avatar
  • 45.6k
1 vote

Are there accepted ranges of "high", "medium" and "low" visual spatial frequency?

The short answer is yes(1), no(2). The quantification of the power spectrum is performed via the Fourier Transform over an image. An image is a matrix that describes the distribution of reflectance (...
A_A's user avatar
  • 10.7k
1 vote
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How to find PSD (Power spectral density) of spatial data

A spectrum estimation method that works well in many cases is Welch's method. The MATLAB implementation is pretty straight forward to use, even when not knowing about the math behind it. Following ...
Arnfinn's user avatar
  • 1,035
1 vote

IFFT of Microphone Array Directivity Response

Your plot shows the magnitude of the array gain vs angle of arrival for the broadside beampattern. Before you can take meaning IFFT of this sequence, you need to follow the following steps. The data ...
aksadv's user avatar
  • 126

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