I want to use Fast Fourier Transform but already trying a simple back and forth transformation doesn't work. The code is import cv2 import numpy as np img = cv2.imread('Picture.bmp',0) f = np.fft...

I tried to filter some signal with fft. The signal I am working on is quite complicated and im not really experienced in this topic. That's why I created a simple sin wave 3Hz and tried to cut off ...

I am trying to implement the split-step fourier method to solve the nonlinear schrodinger equation in optics. It basically treats the linear part and nonlinear part separately. It solves the linear...

I'm trying to implement fast polynomial division using Fast Fourier Transform (fft). Here is what I have got so far: from numpy.fft import fft, ifft def fft_div(C1, C2): # fft expects right-most...

I want to Convolve Lena with itself in the Frequency Domain. Here is an excerpt from a book. which suggests how should the output of the convolution be: I have written the following application ...

I know I can change frequency by whole numbers by changing the variable shift but how can I change the frequency using numbers with decimal places like .754 or 1.2345 or 67.456. If I change the var...

I have a little script for calculating the Fourier Transform of a square wave which works well and returns the square wave correctly when I invert the fft using numpy.fft.ifft(). However, I am unab...

I'm trying to increase / decrease the frequency of a signal using fft and ifft. The first plot is 1hz and the second plot is 2hz which I'm trying to get by altering the fft and ifft values. I can ...

I want to shift an image (represented by a 2D matrix) using the multiplication of its fft by exp(-j*2*pi*x*F), where x is the displacement. I have: input=peaks(200); H=fftshift(fft2(fftshift(input...

I have convoluted an image I created in matlab with a 2D Gaussian function which I have also defined in matlab and now I am trying to deconvolve the resultant matrix to see if I get the 2D Gaussian...

If I have a waveform x such as x = [math.sin(W*t + Ph) for t in range(16)] with arbitrary W and Ph, and I calculate its (Real) FFT f with f = numpy.fft.rfft(x) I can get the original x with ...

I have an ordinary differential equation in time domain as follows: C*du/dt = -g*u + I where I = A*t/tau*exp^(1-t/tau) in the freq domain: u(w) = I(w)/(g*(1+C/g*j*w)) j being the complex nu...

I'm using C++/C to perform forwards and reverse FFT on some data which is supposed to be the pulsed output of a laser. The idea is to take the output, use a forward FFT to convert to the frequency...

This is partly taken from the Matlab fft-documentation: Fs = 30; % Sampling frequency T = 1/Fs; % Sample time L = 130; % Length of signal t = (0:L-1)*T; % Time vector x = sin(2*pi*1*t); % 1 Hz s...