# All Questions

16,634 questions
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### Method(s) to extract text from different sections of a invoice

Since the content of this picture is in Chinese, you do not have to try your methods on this image. A similar image with English content suffice.
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### Checking Parseval's Theorm for Gaussian signal by using Scipy

I'm trying to check Parseval's theorm for Gaussian signal. It's well known that fourier transform of $\exp(-t^2)$ is $\sqrt{\pi}\exp(-\pi^2 k^2)$. So I implement it by using quad and simps. I think ...
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### GCC-PHAT (Generalized cross correlation) always peak at delay=0 on real audio signal

I have studied the GCC-PHAT algorithm to estimate TDOA on audio signals at 2 mics. Here is my MATLAB implementation: ...
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### What is a correct way to find or “guess” a kernel which transforms an image into another image using Fourier Transformations?

Assuming I have two images, apple and orange; also assuming a filter kernel that transforms an apple image into an orange image possibly exists, how would some series of Fourier Transformations (and ...
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### How do I find the frequency of a particular bin in a cosine transform, and two other questions

I have a discrete series of values and I have applied a Discrete Cosine Transform to it, obtaining values like: ...
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### Is there a way to find a picture inside another picture, using only 2D Fourier Transforms of both images?

Can Fourier Transforms of both images tell anything about "likeliness" of two pictures? If yes, how precise? Can it still work if only several pixels are different or can it tell they are same if one ...
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### Problem with Spectral Correlation Function for cyclical signal analisis

I am using the autofam() function in Matlab for the Spectral Correlation Function (link: https://github.com/sayguh/MastersProject/blob/master/matlab/sandbox/autofam.m) for a BPSK modultated chirp ...
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### Some difficult-to-approximate signals to test an signal extracting algorithm

I am searching for some strange signals in order to test an algorithm that I am developing. I've found an article by Donoho and Johnstone where they propose to test the algorithms using Blocks, Bumps, ...
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### Confusion regarding lacunarity of koch curves with same fractal dimension but different orders

I'm trying to use the concept of lacunarity to classify images, as per how a few research papers have done it. To verify whether my equations and implementation are correct, I'm trying to verify the ...
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### Spectrum Inversion Problem

For a signal with $f_c$ (Centre Frequency) $=1200MHz \,\,$ and $BW= 100MHz$ ,which of the following Sampling Frequency ($f_s$) will cause spectrum inversion: A)$\, 287.5MHz \quad$ B)$\,575MHz \quad$...
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### Example of non-equivalence of the two PSD definitions

According to the book Introduction to Spectral Analysis by P. Stoica and R. Moses, the power spectral density (PSD) $P(\omega)$ can either be defined as the discrete-time Fourier transform (DTFT) of ...
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### How to get a heartbeat signal from this data?

I am giving my first steps in data analysis, gathering/cleaning. To learn, I am trying to create a simple code that can detect heartbeats from color variations from the image coming from the camera ...
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### Peak Analysis vs Machine Learning

I am unsure about which approach is "better" (less time good accuracy) for classifying gestures: The system is a doppler radar that returns I and Q signals Approach 1: Have several subject perform ...
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### From filter diagram to state equation

How did we end up with these state variables $Z_1(n+1)$ and $Z_2(n+1)$ from the filter diagram ?
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### How to move a linear block before an Integrator block?

I have the following discrete time blocks which acts as a decimation filter. My objective is to linearize the piecewise linear outputs using $O$ and $G$; the purpose of these two variables is ...
I have few questions I tried to solve regarding nyquist theorem, and I would like to see your opinion if I'm doing it correctly?(one I know the answer second one not sure). 1.Let $f(x)$ and $g(x)$ be ...