In signal processing, a transform is a mathematical technique to convert data in one domain to another. The most common example is using the Fourier Transform to convert data from the time domain to the frequency domain.
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Harmonics on periodic functions
Ok I need to understand how some harmonic calculations work to apply some transforms.
If I have a periodic functiion f(x). And I have the values of that function for several values of x (say x goes ...
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DFT-like transform using triangle waves instead of sin waves
We know that DFT (discrete Fourier transform) breaks down a signal into multiple frequencies of sine waves. Does there exist a transform that does the same thing, but for triangle waves?
For my ...
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Question about harmonic calculations and other functionals for image analysis
I am implementing a method known as trace transform for image analysis. The algorithm extracts a lot of features of an image (in my case features pertained to texture) using a set of transforms on the ...
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Differentiate between two sounds made by same person
I want to know if i pronounce alphabet "A" then i pronounce alphabet "B" how can i detect the difference between these two sounds. I know a sound is characterized by its frequency and amplitude but ...
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Contourlet Transfrom for Image Compression
Before today I had no idea there is any Transform an such; i was only aware with DCT and Wavelet Transforms but today one of my teacher who is doing research on Image processing project had told me ...
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How to model/estimate channel in discrete time with different sampling time?
I want to estimate a channel based on LTE 3GPP EVA with given power delay profile (set of average power and delay of channel taps).
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What are the similarities of Radon and Hough Transform? [duplicate]
What are the similarities of Radon and Hough transform in the context of image processing? They both seem to return the same result. I am aware from another question here that Hough transform produces ...
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Understanding Walsh coefficients
I am working with Walsh coefficients.
I know the intuitive understanding is almost that that they are the degree of connectivity, but it is there a better way of thinking about it? What is the ...
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Global Transforms besides the DFT?
This is a simple question. Fourier analysis gives us the DFT, which is known as a global transform of a signal. In contrast, the Discrete Wavelet Transform (DWT) has a plethora of wavelets, all of ...
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What are the uses of those three types of wavelet transformations?
In my studies of wavelets, there appear to be 3 different families of them:
The Continuous wavelet transform
The Discrete wavelet transform
The Redundant wavelet transform
They are all based on ...
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41 views
Combining Distance Maps
I have two distance maps that describe distances from blue segment and the red segment. I need to compute a single weight map that describes transition from blue segment to the red segment. The weight ...
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What do colored noises look like in the time domain?
I understand that the time domain representation of white noise looks like impulses. How do colored noises like brown, pink etc. look like when we perform an inverse Fourier Transform on them ? What ...
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Gradient Domain Reconstruction - Scaling Problem
I am implementing reconstruction of image from gradient domain. This requires solving the following partial differential equation (a Poisson equation) on a 2D grid:
$$\nabla^{2}I=\mathbb{div} G$$
...
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Wang Transformation
I'm essentially a math student working on algorithms for a chemistry problem involving rotational spectra, and I keep coming across references to Wang transformations but have been unable to track ...
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Does taking the Hilbert transform extract the envelope of audio signals?
I want to extract the envelope of music signals with a sample rate of 44.1kHz.
I used the MATLAB command: abs(hilbert(mysignals)), but the resulting signal is ...
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How do I create a frequency vs time plot?
I'm a chemical engineer, not an EE, so this is a bit difficult.
I'm trying to figure out how to take amplitude vs time data and transform it into frequency vs time. My first instinct is to slice my ...
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applicability of compressed sensing
From what I have heard, compressed sensing can only be utilized for a sparse signal. Is this correct?
If that is the case, how can a sparse signal be distinguished from any bandlimited signal? Every ...
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298 views
How to compute Discrete Cosine Transform
Can anyone please help me understand the 2D equation of DCT?I find it hard to understand it in terms of how to apply the equation.
For example if I have an 8x8 image and I will apply 2D-DCT to every ...
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Filtering RANSAC Estimated Homographies
I am using RANSAC algorithm for homography estimation between pairs of images taken with cameras which do not have any translation between them (pure rotation and change of scale/zoom). It works well ...
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What does the normalization step of the Haar wavelet transform represent?
When you perform the Haar wavelet transform, you take the sums and differences, then at each stage, you multiply the entire signal by $\small\sqrt2$.
When taking the inverse transform, you multiply ...
