15
votes
Accepted
Does a simple photograph contain more information than a complex painting?
It depends how you define the term "information" or "entropy".
The conventional definition of entropy of an image is to think the image as a two-dimensional matrix of pixels and
$$H = - \sum_k p_k \...
- 6,650
8
votes
Accepted
How does the assumption that symbols are equi-probable hold
If I draw a number uniformly between zero and one, what is the
probability that they are equal? Mathematically, it should be zero but
I don't recall why? Can somebody please help in explaining why ...
- 6,650
5
votes
Why expected value is optimal?
Nothing is "optimal" in an absolute sense. Something is or is not optimal according to a defined, precise criterion.
Say you have a real random variable $X$. You want to find a number $m$ ...
- 15.4k
3
votes
What are your tips for DSP self-study?
DSP would be a quite broad subject and where to start would depend on your ability to pick up information, learn, understand and implement it. A basic course for supplying us with the basics to ...
- 79
3
votes
What Resources Are Recommended for an Introduction to Signal Processing (DSP)?
I would add to the list the book "Digital Filters", by Richard Hamming. A short classic, rather than a heavy tome.
2
votes
Seeking compressive sensing imaging demo in MATLAB
The following links have papers and usually have the associated code:
l1 magic
Rice University
SparseLab
SPGL1
Hope that helps.
- 2,881
2
votes
What Resources Are Recommended for an Introduction to Signal Processing (DSP)?
https://www.amazon.com/dp/B01MS8W9XI
This book will go through different projects that will teach the reader how to write software: to improve their singing, synthesize different guitar sounds, ...
2
votes
Accepted
Can we band pass filter QPSK signal?
Yes, you can bandpass the QPSK signal before matched filtering and demodulation if you wish to do so, but what you need to devote some thought to is whether such an action is a wise decision. The ...
- 20.7k
2
votes
Overview Noise Reduction Techniques
The frequency domain conjugate multiplication (correlation) of the received signal with the reference signal followed by the power delay profile will provide you the overall signal to noise ratio. As ...
- 23
2
votes
Origin of brightness artifacts in intensity resolution compressed images
I've taken the original tiff and just set a low threshold for 1bit quantization (conversion to black and white):
so we can clearly make out that these artifacts look very circular, and placed in ...
- 32k
2
votes
Does a simple photograph contain more information than a complex painting?
Based on your provided images, the painting should involve more information.
However, the sky scene might include perceptually invisible components that a mathematical algorithm would treat as ...
- 28.4k
2
votes
Matched Filters for attenuation detection?
Your interpretation of the matched filter for radar seems almost right, just to be sure, let me reiterate a bit: Think of it this way: we're sending a pulse function $p(t)$. If a target in distance $d$...
- 2,463
2
votes
Accepted
Given a impulse responce can we derive a state space model?
you might need some procedure like the prony method to convert your impulse response (as a bandlimited and uniformly-sampled signal) into a sum of decaying exponentials and from that obtain a sum of ...
- 21.1k
2
votes
Accepted
From Mathematics to DSP
In general, Maths to audio signal processing is a very natural progression. I seem to recall my Master's and PhD supervisors both did their undergraduate degrees in Maths.
To your questions:
This ...
- 817
2
votes
Accepted
Does 46 dB gain of a filter for a frequency imply 200 times more amplitude?
can we expect to get 200 times higher amplitude in the output of the filter comapre to the input of the filter
Yes.
For a sine wave input the amplitude of the steady state output is simply the ...
- 47k
2
votes
What helped you in reading and implementing papers and coming up with original ideas in computer vision/graphics?
People working in computer vision/graphics may have very different backgrounds: computer programming, high-performance computing, signal processing, image analysis, optimization, machine learning, etc....
- 32.1k
2
votes
Radar type application for narrow band only?
These constraints absolutely exist. There are the norm! We could only wish in our wildest dreams to use as wide as bandwidth as we like. There are many areas in a radar system that place limitations ...
- 2,646
2
votes
Accepted
What do you call the random Gaussian vectors in compressed sensing?
The collection of scalar products is often called measurement. The collection of vectors (each being an atom) can be called measurement dictionaries or sensing dictionaries. This is not specific to ...
- 32.1k
2
votes
What do you call the random Gaussian vectors in compressed sensing?
In most of the literature I am familiar with (signal processing), these vectors are considered collectively as rows in a matrix, i.e.
$$\mathbf y = \mathbf E \mathbf x$$
where the $(M \times 1)$ ...
- 1,322
2
votes
Fourier Transform of the conjugate of a complex function
$\mathcal{F}\{x^*(t)\} = X^*(-f)$
Taken from the table of Fourier transform theorems on slide 6 of this document: https://www.comm.utoronto.ca/~dkundur/course_info/316/KundurFTProperties_handouts.pdf
...
- 121
1
vote
Given a impulse responce can we derive a state space model?
Yes and no.
There, wasn't that easy?
Yes, people do construct models from impulse responses - it's called "system identification".
No, not without outside guidance (as, for instance, an idea of the ...
- 12.9k
1
vote
Is there a noise cancellation technique for over-lapping spectra?
First of all the Wiener filter does not remove the noise but reduce it for WSS signals.
It does this based on the relationship between the power spectral density of the clean signal $x[n]$ and ...
- 28.4k
1
vote
Origin of brightness artifacts in intensity resolution compressed images
Maybe at some point the image was reconstructed as stippling circular brush strokes by a greedy algorithm. Greedy, because in Marcus's high-contrast version of the image it looks like some darker ...
- 13.6k
1
vote
Accepted
Signal processing research idea
This is very simple. You need an inter-disciplinary domain where all (and more) of your interests are satisfied, while being very publishable, employable and fun. Easy!! Jump into the bleeding edge of ...
- 1,770
1
vote
Why do mobile phone calls produce a vibration when they are near a speaker?
The Global System for Mobile Communications (GSM) is a 2G (2nd generation) technology which uses the time division multiple access (TDMA) method. With this method, each phone transmits within its own ...
- 13.6k
1
vote
Why do mobile phone calls produce a vibration when they are near a speaker?
A little background...
How a speaker works: Speakers are controlled by driving small diaphrams with a magnet and that magnet is controlled by wires that take isolated 'wired' signals and convert them ...
- 119
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