14 votes

What Kind of Features Can I Extract from a Signal

Some Features: Mean. Variance. Skewness. Kurtosis. Dominant 3 frequencies in the DFT. Energy of the 3 dominant frequencies. Max Value. Min Value. Median. Total Variation. Usually I'd compute them in ...
  • 42.5k
8 votes

How to Use Maximum a Posteriori Probability (MAP) in Classification Task

I will try to give you some intuition into it by a different example. Think we have 3 machines which can generate the numbers 1, 2, 3. The first machine generates the number 1 with 80% and the ...
  • 42.5k
7 votes

Is there a public repository of labeled sound files coming from an industrial area?

Freesound is a repository of sound files categorised by user-defined tags. Through those, you can spot what other users have labeled industrial sounds but be prepared that some of those might be ...
  • 10.1k
6 votes

Python: Least Squares Support Vector Machine (LS-SVM)

There is a package called FukuML. In their description (Version 0.4.1) they write: Support Vector Machine Primal Hard Margin Support Vector Machine Binary Classification Learning Algorithm Dual ...
  • 42.5k
5 votes

What Kind of Features Can I Extract from a Signal

In addition to the features mentioned so far I would like to mention measures of complexity such as: Shannon Entropy LZ Complexity Fractal Dimension There are also Fourier Descriptors (as hinted ...
  • 10.1k
5 votes

Subgradient Method for K-Means Like Problem

You should use something like Robust Convex Clustering: Assume that we are given $ n $ data points and each data point is described by a $ d $ dimensional feature vector. We collectively represent the ...
  • 42.5k
5 votes
Accepted

If a K-NN ($ k $ Nearest Neighbors) Algorithm Performs Very Well for Low $ k $, Can Something Be Inferred About the Data Set?

If the result is consistent with a large test set than it means your training data is dense and well define the degrees of freedom of the problem. If the training set was small it means there is a ...
  • 42.5k
5 votes

System classification: unit-time delay

You are right that a distributed system could be "something like a transmission line". Note that the system $$y(t)=x(t-T)\tag{1}$$ is a simple model of a transmission line, where just a frequency-...
  • 80.9k
4 votes
Accepted

Need critical help: How to detect and distinguish two very similar looking signals?

As Conrad pointed out, a correlator is probably your best bet. The correlation of a signal with itself (also known as its self-similarity) is larger than its correlation with any other signal (except ...
  • 13.9k
4 votes

Feature extraction for sound classification

Non-verbal Audio (let alone environmental) seems to be the little brother to main stream machine learning media types like images, speech, text. To answer your question is it possible to train a ...
4 votes
Accepted

Classifying 2 Classes of Ultrasound Signal Using Machine Learning by Frequency Domain

One simple way is to create a feature set based on the energy on the different frequency bins. If the case above is representative, even "small guns" (Linear classifiers) will solve this. ...
  • 42.5k
3 votes

Feature extraction for sound classification

Here is a solution for sound classification for 10 classes: dog barking, car horn, children playing etc. It is based on tensorflow library using neural networks. Features are extracted by converting ...
  • 151
3 votes

What Kind of Features Can I Extract from a Signal

Hello I will be brief and I hope you understand, due to the shape of your signal I think it is best treated with wavelet transform base HAAR, the reason for using this transform is that it will give a ...
3 votes

MFCC feature vector from wav file

Have a look at these two python libraries that provide a number of audio features easily from WAV files, including MFCC. Librosa: MFCC docs, github Madmom: MFCC docs, github Good luck!
  • 1,730
3 votes

Upsampling vs downsampling. Which to use when?

You should use the one you need for your problem, when you know which components of your signal are of interest to you. Let's say you have in your electronic editing an ADC digitizing 40M samples per ...
3 votes

Audio classification without deep learning

From what you've mentioned it looks like the task is for environmental sound event detection. I think that the best starting point for you is to check the DCASE challenge (Detection and Classification ...
  • 10.7k
3 votes

How is this system nonlinear

This system may cause a hallucination because of its similarity to the algebraic equation $y = x + 1 $ which is a linear one indeed as stated in the wikipedia link to System_of_linear_equations ...
  • 27.1k
3 votes

How is this system nonlinear

A linear system means that the system's output should scale with the input, and the system's output should combine given two inputs. Look at the scaling property, you scale the input and this results ...
  • 2,798
2 votes

Binary classification of grayscale image with little texture

Two large classes of techniques that may be of interest to you: Mumford Shah functional based techniques. Active Contour techniques. Some googling on these terms should open some new doors for you.
  • 193
2 votes

What are characteristics of shadows in an image given an outdoor setting from an image processing point of view?

The characteristics of the shadow are as follows: It is always dark regardless of the color of the object or the color of the light used to make a shadow It only shows a dark outline of the object It ...
2 votes
Accepted

What are characteristics of shadows in an image given an outdoor setting from an image processing point of view?

Shadow has very specific properties that makes it very clear way of making it distinguishable from the regular object. A lot of work in the area of background subtraction and surveillance has been ...
  • 5,577
2 votes

What are characteristics of shadows in an image given an outdoor setting from an image processing point of view?

The edges of the shadows are crisper where they are nearer to the shadow caster. Also, since the sun is so far away, beams of light are essentially parallel when they reach us, which means that ...
2 votes

Pyramid Match Kernel: How to fit grid around data points?

No, that's not it. Look at the last sentence of your quote: ... which may be enforced by scaling the data to some precision and truncating to integer values. So this is exactly what you do. Take ...
  • 4,941
2 votes
Accepted

Finding filaments in high dimensional space

Following my comment, I now have time to post it as an answer. If you expect that a large enough portion of the vectors belong to that line, you can use RANSAC. RANSAC works by selecting a small and ...
  • 1,450
2 votes

What is a good way to distinguish aircraft noise from other sounds?

You need to train a classifier. The way I would approach it is to allow users to submit audio recordings through your app, and indicate which sections of the recordings contain the plane. This would ...
  • 2,837
2 votes

How do I retrieve texture using GLCM and classify using SVM Classifier?

This article deals exactly with the same type of supervised classification based on labelled GLCM classes: GLCM Textural Features for Brain Tumor Classification
  • 121
2 votes
Accepted

How to emulate human sound recognition

I do not think that there is a standard approach to this problem, because as far as I know it has not yet been solved satisfactorily. I believe that you can find a solution to a (very) simplified ...
  • 80.9k
2 votes
Accepted

Subgradient Method for K-Means Like Problem

I don't see why you would like to use subgradients for that. Correct me if I'm wrong, but when the problem is fully differentiable (kmeans actually is), the subgradient is the gradient vector $\nabla ...
  • 5,255
2 votes

How does the PASCAL VOC challenge evaluate the task of object detection?

The detection task is: Given an image $I$, does it contain a sub-image $S$ (or an object $S$)? There are several things that can happen: $I$ contains $S$ and the detector says $I$ contains $S$ This ...
  • 23.1k

Only top scored, non community-wiki answers of a minimum length are eligible