# Tag Info

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
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

### 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
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

### 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

### 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
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
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

### 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

### 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/...

### 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

### 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

### 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
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

### 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

### 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
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

### feature selection for classification for rare classes

Try one of Arizona State - Feature Selection Algorithms for feature selection: ...
• 168

### 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 ...

### 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
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
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

### 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

### 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: ...
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 ...
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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