Questions tagged [feature-extraction]

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7
votes
1answer
5k views

What's the correct graphical interpretation of a series of MFCC vectors?

I'm studying speech-recognition, in particular the use of MFCC for feature extraction. All examples I've found online tend to graph a series of MFCC extracted from a particular utterance as follows (...
4
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4answers
434 views

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, ...
4
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2answers
816 views

Using Convolution as Feature Extraction

I am now studying image processing in my spare time. My understanding of convolution is about 'response to a specific filter': When we have a raw image, or raw signal; and a filter, aka kernel; we ...
3
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2answers
4k views

ORB Algorithm: What Is Intensity Centroid?

So, I am reading a paper about ORB: An Efficient Alternative to SIFT or SURF and it happens to calculate the direction of corner from it center . According to Rosin the author of the paper;moments of ...
2
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1answer
1k views

MFCC delta: How to compute delta, in real time, with no future frames?

I am trying to compute Delta coefficients for real-time audio analysis. As far as I know, a valid formula is: $$d_t= \frac{\displaystyle\sum_{n=1}^{N}n\left(c_{t+n}-c_{t-n}\right)}{2\displaystyle\...
2
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0answers
126 views

How do I extrapolate a 1D chirped signal?

Following a past question, I'd like to extrapolate a signal like the one below: (red is signal, blue is the the extrapolated ) ...
2
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1answer
390 views

Common Spatial Pattern for EEG Signals

I am having difficulty in understanding the use of CSP for EEG signal feature extraction and subsequently. Since I am using two classes, this query will be restricted to it. In essence CSP requires 2 ...
2
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2answers
467 views

How to extract features of individual spikes in non-negative signal?

I have data of non-negative (in the sense there's no signal below baseline) spiking waveforms, which are in the form of a 1D array of numbers: Spikes that cross some threshold are considered real ...
2
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0answers
82 views

Is there a way to extract the difference between the 2 signals? Fitting?

I'm very new to signal processing and have been struggling this far. I have a device that measures the signal due to the magnetization of iron particles. In order to calculate the response of the ...
1
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2answers
97 views

Why do we need multiple layers in each octave and multiple octaves in SIFT?

I skimmed through the SIFT paper. I understand that there are multiple octaves, which are composed of multiple layers. The layer $k$ of an octave (btw, where does this name come from?) corresponds to ...
1
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2answers
2k views

Is there a program to extract features from an audio signal?

I am looking for a way to take a .wav file and extract features from it that could be used for further classification (the features could be MFCC statistics, an autoencoder representation, etc.). I ...
1
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1answer
39 views

What is the purpose of dividing an audio signal into segments and analysis each segment?

I read bunch of materials for extracting feature from audio signal and they all tell me to break signal into segments, why don't we analyze all the audio signal? I don't know what are the advantages ...
1
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1answer
1k views

Why is LPCC and LPC used in speech recognition

I am currently trying to understand why LPCC and LPC is being used in speech recognition and why? LPC as I understand is model similar to source filter model, modelling speech production, and LPC ...
1
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2answers
705 views

Detecting trough widths and locations in 1d signal

I have the following function obtained from averaging 2d camera image over one axis, where detection of aligned objects is desired: I need to detect (roughly speaking) locations and widths of the ...
1
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1answer
2k views

How to extract prosodic cues from a wav file using Python

How do I extract the following features as from wav files in Python - Voicing rate (Voice rate) - frequency of phonemes while speaking, and represents the pace of a conversation Number of ...
1
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1answer
144 views

How signal moments work?

We know that moments extract important features of a signal that has no redundancy. For example Zernike moment gives us rotation invariant data of a signal like image or Fourier gives us frequency of ...
1
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1answer
115 views

Fast Vocal Tract Length Normalization(VTLN) implementation?

My team is building a speech recognition model. As far as I know, Vocal Tract Length Normalization (VTLN) is an effective warping method that may help improve the model performance by diminishing ...
1
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1answer
505 views

what is the output of MFCCs?

I had calculated 13 MFCCs coefficients of a speech signal and i got output in the form numerical vectors please see below figure. My confusion whether it is in time domain or frequency domain. suppose ...
1
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2answers
242 views

Understanding of Histogram-of-Oriented-Gradients

I am learning about HOG and I understand it from here. A well-explained page with an example. I am not understanding this concept that how it works A 16×16 block has 4 histograms which can be ...
1
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2answers
345 views

Scratch Detection On Noisy Textured Surface

I wish to extract long thin scratches from the noisy background image.I have tried several ways such as stacking smoothed image with input image to remove some of the noisy background patch before ...
1
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1answer
43 views

How does a telephone change your voice? [closed]

Is it due to vocal length normalization during MFCC? Please be kind enough to explain.
1
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1answer
123 views

How to Describe the Color of an Image Patch?

I want to describe the color of an image patch (say, of size 5x5) centered around a pixel of an RGB image. The most straightforward way to do that is to calculate the average color over that patch and ...
1
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1answer
3k views

Feature Extraction of FFT for One Class SVM

I'm looking for a good way of extracting features from the frequency domain of vibration data for a one-class support vector machine. The image below shows an example from the dataset found in this ...
1
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1answer
2k views

How do I get texture feature images from GLCM texture analysis?

In this paper under section 2. "Proposed Methodology", the author creates a GLCM from an image and then extracts texture features resulting in a new image for each feature. I've seen other authors do ...
1
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1answer
39 views

Understanding the Threshold Process in Harris Corner and Edge Detector

I have read the paper Chris Harris , Mike Stephens - A Combined Corner and Edge Detector about the Harris Corner and Edge Detector, but I didn't understand the point that after low and high threshold ...
1
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1answer
45 views

What is the HOMING operator?

I was reading "Optical Recognition Systems" book and in chapter 3.3.2.3 where methods for full genetic programming are described, a paper is describing an ADF (automatically defined functions) like ...
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0answers
35 views

Calculate the tension of a triad of notes

I'm trying to implement and calculate the tonal tension of a triad (and its harmonics) following the definition given here: https://pdfs.semanticscholar.org/f05e/56c9548fa18c64efeed248742e3a6afb0c02....
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0answers
41 views

zernik moments and Local binary pattern

Both of zernik moments and Local binary pattern (LBP) are feature detectors and can achieve rotation invarient. How can they achieve rotation invarient over an image? What are the advantages of ...
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0answers
25 views

Recognize irregular repetition of unknown feature (stamps at random locations)

I have an image which is generated by convolution between (1) a simple small patch and (2) larger image composed of localized point-like features (e.g. slat-and-pepper noise, sum of shifted $\delta$-...
1
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0answers
583 views

What are the drawbacks of Harris corner detector? [closed]

What are drawbacks of Harris corner detection when trying to match features in a stereo pair? I notice that whenever I use Harris corner detector to match features, images with strong occluded areas ...
1
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0answers
63 views

Image feature extraction for discrimination

I am using linear/quadratic discrimination to guess who is the artist of a painting. All the images are RGB format and I use matlab. I have used both original image and images that are resize to be ...
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0answers
249 views

VLFEat: How to extract the SIFT descriptor without SIFT feature detection?

I am using the MATLAB interface to the VLFeat toolbox in order to calculate a SIFT descriptor for image patches extracted around key points. Due to the greater framework of what I'm doing, I cannot ...
1
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1answer
151 views

Music Recommendation [closed]

I have idea of creating Content based Music recommendation system based on Music signals, Now I am asking how I can extract signal features from Music and how to represent them. There after I may find ...
0
votes
1answer
124 views

feature selection for classification for rare classes

I have a spectrogram of a signal and want to classify it. I used different features such as MFFC, the density of power spectrum and other common features and classify using the random forest, but I ...
0
votes
1answer
98 views

What is the use of perception calculation in Speaker Identification?

I'm currently trying to find audio features to train a neural network that distinguishes people, and I came across MFCC which is used a lot for speech verification. As far as I understand the ...
0
votes
1answer
1k views

Feature Vector from an audio signal [closed]

I want to develop a feature vector from an audio input. Up to now, I have identified fundamental frequency, max phonation time, timbre to be among the key features to be identified. Can someone ...
0
votes
1answer
26 views

KLT for an ECG Signal

I am currently searching for methods of feature extraction from an ECG signal and I've stumbled upon the Karhunen–Loeve Transform. I've read some papers and I think I get the basics but my question ...
0
votes
1answer
62 views

How to make series circle shift invariant

I have a series of numbers. They may be integer, floating, or ...
0
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0answers
24 views

How to plot ROC Curve of feature detecttion algorithm? [closed]

I want to compare the performance of feature detection algorithms like Harris, Shi-Tomasi, MSER, ORB, FAST, BRISK and KAZE using ROC Curve. I found that I need TP rate FP rate. How do I derive the TPR ...
0
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0answers
10 views

Mutual information smaller on data subsets compared to entire data set

I am estimating the mutual information for a continuous data set using the kNN-based mutual information estimator proposed by Kraskov et al [1]. Lets consider two features $X$ and $Y$, and the ...
0
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0answers
13 views

how to implement Bark filter bank on the power spectrum for PLP feature extraction?

So the implementations for PLP feature extraction I have seen in python and Matlab, are as follows: suppose the FFT features of an audio signal are of the size 257 (512 point FFT). if we have one ...
0
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0answers
24 views

How can I stitch bottom of some image to topside of another image by erasing as much overlapped image as possible?

I have 2 images of size 1920*1080 and I want to try image-stitching on them. These are images (images are from wind turbine blade.) This is the first image And the second image. I already have ...
0
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0answers
15 views

How does Lowe's ratio test work when you compute more than 2 nearest neighbours?

Lowe's ratio test can be used to discard matches that are possibly irrelevant or noisy. However, it isn't clear to me how the ratio test should be performed when you retrieve more than 2 nearest ...
0
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0answers
23 views

How to save MFCC features and frame energy of several wav files to one .npz file for machine learning training?

I am creating a English-Italian corpus of around 100 hours of English audio from LibriVox aligned with their Italian textual translation. The alignment is at a sentence level and the corpus consist of ...
0
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0answers
19 views

Rule of thumb / Best practice for Audio (voice) data normalization for use in Classification

TRIVIAL QUESTION: I am currently working with some audio data of speech utterances. I am attempting to perform classification on the data based on the phonemes. This means that I manually label the ...
0
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0answers
13 views

Calculating Marginal Hilbert Spectrum across IMFs using mhs() in MATLAB

I'm working on an EEG dataset from which I need to extract the power of five different frequency bands. I'm doing this by performing Hilbert Transform on the ICA activations from performing channel-...
0
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0answers
33 views

Wind turbine vibration analysis approach

This is going to be a bit of a long post. My questions are: Do the 5 signal processing steps look "correct"? Next steps could be to perform order analysis, and extract features from time, frequency, ...
0
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0answers
29 views

How to approach Feature Extraction and Feature Selection part in machone learning in python?

I am a bit new to machine learning and I have the following questions: Question 1: When dealing with feature extraction with signals from sensors, what is the typical approach to extract features ...
0
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0answers
53 views

Feature extraction for exponentially damped signals

I am looking into exponentially damped signals where it is a stationary signal (after implementing the Adfuller statistical test) and I would like to look into how can I extract meaningful features ...
0
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2answers
81 views

log base in log-power spectral features

Is the log in log-power spectral features natural logarithm, or common log of base 10? does it even matter? I found sources for how to calculate it, but they all call it 'log'. no one mentions the ...