Questions tagged [local-features]
The local-features tag has no usage guidance.
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Is there a way to measure an image SNR blindly?
Are there known techniques to estimate the SNR of an image in small neighborhoods (say like 11x11) without any knowledge of the clean image, with arbitrary content ? Denoising is not required.
Update:...
user7657
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Invariances of FFT-based Image-Registration vs. SIFT-Features
TL;DR: I don't understand how invariant FFT-based image-registration techniques are to object alterations (scratches, marks etc.) in comparison to SIFT-features.
I want to build kind of a feature-...
- 201
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Are location in BRIEF feature descriptor reused?
In the BRIEF feature descriptor ("BRIEF: Binary Robust IndependentElementary Features", Calonder et al., 2011) they investigate five different methods of choosing point pairs to compute the ...
- 133
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Corner detector vs feature detector
In the literature, I see "corner detector" and "feature detector" are interchangeably used for these methods e.g. Harris, Shi-Tomasi, FAST, etc.
What is the difference between a ...
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What Is an Oriented Gaussian Second Derivative Filter
In the paper: Detecting and Localizing Edges Composed of Steps, Peaks and Roofs, the authors refer to an image filter as an oriented second-derivative Gaussian filter. I'm trying to figure out what ...
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Use sparse optical tracking to track a Bounding Box object
I need some help on solving this issue. Any tips are appreciated.
The goal of the project is to try to track a Bounding Box object, chosen arbitrarily in an image, throughout many frames of a ...
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What are the ranges of values for each audio feature/descriptor?
I need to normalize some audio feature measurements I've done with the software Wolfram Mathematica.
Coming from a non signal processing background, I have some difficulties understanding what ...
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760
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Sum of Squared Intensity Difference for block matching with ORB features, c++
I am trying to implement feature matching algorithm between image reference and image current.
The pipeline is as follows:
...
- 143
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412
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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 ...
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Finding Local mean value of pixels of window
I want to solve the equation (2) in the attached picture which tells the local mean value. But i don't have any idea about how to evaluate this equation using matlab code. could only guess w indicates ...
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How can I extract information about timbre from a .wav file. In which form can I study those features?
To study the frequencies of a piece of audio, we can generate a spectrogram from that audio file. I'm wondering how the features of timbre are saved in such tiny wave files, and how we can extract ...
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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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272
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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 ...
- 243
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Classification test by embedding true positives in high frequency recordings
I'm evaluating a cyclostationary approach to signal classification. My first step in doing so was generating signals and embedding them into a few specified parameter sets of the Watterson channel ...
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Relationship between Wavelet transform and Fourier Power Spectral Density
Is there anyway to obtain the Fourier Power Spectral Density from a wavelet transform of a time series?
I am particularly interested in this problem because I was wondering if there is any ...
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