11
votes
Accepted
What's the correct graphical interpretation of a series of MFCC vectors?
The way MFCC's are always used is by feeding them into the classifier. This can be done on a frame-by-frame basis (12x1 vector), or by concatenating (...
- 10.4k
6
votes
Accepted
What Are the Differences in Four Different Types of Third Order Image Moments (Skewness)?
It it based on the definition of Central Moments on 2D grid given in the Wikipedia Page.
$$ {\mu}_{pq} = \int\limits_{-\infty}^{\infty} \int\limits_{-\infty}^{\infty} (x - \bar{x})^p(y - \bar{y})^q f(...
- 39.1k
6
votes
Palm Pilot Graffiti
It seems most of the data is in Graffiti (Palm OS) - Wikipedia.
It seems the technology is related to Unistrokes technology (U.S. Patent 5,596,656, granted in 1997).
Since the model relies on single ...
- 39.1k
6
votes
Accepted
Palm Pilot Graffiti
If you are looking for a good explanation of some of the methods used in projects like GRAIL look here:
Back to the Future of Hand Writing Recognition
- 176
5
votes
How to Describe the Color of an Image Patch?
Another approach which might be appropriate in your Bayesian approach (Filter Particle) would be Mean Vector + Covariance Matrix.
Even for that you could employ your idea of weighing (Which is ...
- 39.1k
5
votes
Accurate phase calculation in sinusoidal linear regression?
What other "modern" methods exist for accurate phase extraction?
Unless the frequencies in the signal are phase locked to your sampling clock an FFT is not a great way to determine either ...
- 30.6k
4
votes
Accepted
ORB Algorithm: What Is Intensity Centroid?
p and q - order of the moments, it is the analogue of the mechanical moments (i.e. of force or inertia). Image moments are very basic properties of image, invariant to rotation, could be used as ...
- 239
4
votes
Accepted
Understanding GCC-PHAT as a Feature
Let there be two microphones, $x_1(t), x_2(t)$ capturing a source, $s(t)$, with some additive noise $n_{1,2}(t)$ that is uncorrelated with the source and with each other (i.e., its effect can be ...
- 371
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votes
Palm Pilot Graffiti
Surprised? DARPA (GRAIL project?, et.al.) supported handwriting recognition research circa 3 decades earlier, and on mainframes less powerful than a PalmPilot 1000.
Hawkins talks a bit about ...
- 33.8k
3
votes
Is there a program to extract features from an audio signal?
The openSMILE audio feature extraction toolkit may be able to provide the functionality you desire, where the input is a .wav file and the output extracted audio features. See: http://audeering.com/...
- 131
3
votes
Why do we need multiple layers in each octave and multiple octaves in SIFT?
In music theory, an octave is an interval in frequency, from a frequency $f$ to frequency $2f$. For example "an octave higher" means "twice the frequency". Expressed as wavelength ...
- 12.3k
3
votes
What are features in signal processing using a more tangible or less abstract description
A feature is a number that describes one aspect of a signal.
Signals can be very complex, and the simplest analysis tools (like a time plot, a spectrum, or an energy measurement) don't tell you ...
- 13.5k
2
votes
Feature Vector from an audio signal
Have a good read of various features that can be extracted from popular audio analysis libraries like librosa: https://librosa.github.io/librosa/feature.html
Fundamental frequency (F0) can definitely ...
- 1,690
2
votes
Accepted
How signal moments work?
I dont think there is a common framework for defining all those operators. Each of them were developed by different people, at several moments of the history. They are being integrated day by day onto ...
- 1,302
2
votes
ORB Algorithm: What Is Intensity Centroid?
Because wo want to get the centroid of the image(a block/patch) by the intensity.
m00:p = q = 0,sum the intensity matrix.
m10:p =1,q = 0,sum of the x-direction.
m01:p = 0,q = 1,sum of the y-direction.
...
- 21
2
votes
Using Convolution as Feature Extraction
Your understanding of the convolution process is correct. However, note that in the convolution the kernel is first mirrored before the dot product. Though, for a symmetric kernel this does not matter....
- 6,038
2
votes
Accepted
What is the use of perception calculation in Speaker Identification?
Well, I don't know whether it'll actually help you – you just said it would!
Now, in any case, using an algorithm to extract features from a signal that mimics or resembles human perception should ...
- 25.7k
2
votes
feature selection for classification for rare classes
Try one of Arizona State - Feature Selection Algorithms for feature selection:
...
- 168
2
votes
How to extract prosodic cues from a wav file using Python
This project Speech Signal Processing Toolkit (SPTK) provides several features you are looking for. Here is a good wrapper around it https://github.com/r9y9/pysptk
This wrapper is using a slightly ...
- 19
2
votes
Why is LPCC and LPC used in speech recognition
I think a high-level explanation is the right thing to give here:
For recognition of a producing process (in this case: speech) from a signal (in this case: audio), you need to find a mapping from ...
- 25.7k
2
votes
Accepted
Features Used for Instrument Recognition?
Well the state of the art performance on such tasks is achieved by deep neural networks, and especially, the convolutional ones (CNNs) set you free of extracting hand crafted features. The network ...
- 5,167
2
votes
Accepted
What is the purpose of dividing an audio signal into segments and analysis each segment?
Analyzing signals per segments, with proper windowing, is a way to cope with non-stationary in audio samples. With full-size analysis, features can get mixed. Segment-splitting is thus at play in ...
- 29.6k
2
votes
Working with a sound's magnitude instead of amplitude
There is no reason why your piezo shouldn't be able to produce a bipolar output, if you use proper biasing and/or preamp. See for example https://www.homemade-circuits.com/diy-contact-mic-circuit/
...
- 30.6k
2
votes
Accurate phase calculation in sinusoidal linear regression?
Do an FFTShift (rotate the data halfway) before doing an FFT for phase analysis. That will re-reference the measured phase to the center of your data, not to potential circular discontinuities at the ...
- 33.8k
1
vote
Scratch Detection On Noisy Textured Surface
I tried PHOT (suggested by @applesoup) using the unofficial implementation given under https://github.com/thinkng but it did not work for these image sets. Maybe one needs to further investigate or ...
- 5,167
1
vote
How does a telephone change your voice?
In the case of switched analog POTS phone lines, the audio response is shaped by the limited frequency response of the carbon microphone and the speaker in the handset.
- 33.8k
1
vote
Accepted
How can I extract information about timbre from a .wav file. In which form can I study those features?
I think the time history of the wave file is enough to obtain all sorts of features. There are mathematical formulae to extract the features from a given time series.
Some important features are:
...
- 181
1
vote
How to make series circle shift invariant
A possible way to approach the problem would be to extract the maximum values of the discrete circular convolution of each pre-normalized sequence with an NXN matrix formed by the elements of an ...
1
vote
Common Spatial Pattern for EEG Signals
I am not sure I understand your question, but for the particular question
How are features of the EEG Signal extracted then?
CSP gives you a matrix $W$ that represents a spatial transformation of ...
- 111
1
vote
Accepted
Feature Extraction of FFT for One Class SVM
Assuming you have epochs/segments of data. For this kind of signals, it is a safe approach to extract features using wavelet representations.
Using FFT might work as well, but I dont know how ...
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