scholarly journals FFT based convolution

2010 ◽  
Author(s):  
Gaetan Lehmann

The Fourier transform of the convolution of two images is equal to the product of their Fourier transform. With this definition, it is possible to create a convolution filter based on the Fast Fourier Transform (FFT). The interesting complexity characteristics of this transform gives a very efficient convolution filter for large kernel images.This paper provides such a filter, as well as a detailed description of the implementation choices and a performance comparison with the “simple” itk::ConvolutionImageFilter.

2008 ◽  
Vol 3 (4) ◽  
pp. 74-86
Author(s):  
Boris A. Knyazev ◽  
Valeriy S. Cherkasskij

The article is intended to the students, who make their first steps in the application of the Fourier transform to physics problems. We examine several elementary examples from the signal theory and classic optics to show relation between continuous and discrete Fourier transform. Recipes for correct interpretation of the results of FDFT (Fast Discrete Fourier Transform) obtained with the commonly used application programs (Matlab, Mathcad, Mathematica) are given.


2016 ◽  
Vol 31 (2) ◽  
pp. 957-965
Author(s):  
Weihua Zheng ◽  
Shenping Xiao ◽  
Kenli Li ◽  
Keqin Li ◽  
Weijin Jiang

2002 ◽  
Vol 35 (4) ◽  
pp. 505-505 ◽  
Author(s):  
David A. Langs

The fast Fourier transform (FFT) algorithm as normally formulated allows one to compute the Fourier transform of up toNcomplex structure factors,F(h),N/2 ≥h> −N/2, if the transform ρ(r) is computed on anN-point grid. Most crystallographic FFT programs test the ranges of the Miller indices of the input data to ensure that the total number of grid divisions in thex,yandzdirections of the cell is sufficiently large enough to perform the FFT. This note calls attention to a simple remedy whereby an FFT can be used to compute the transform on as coarse a grid as one desires without loss of precision.


In 1965 a technique called Fast Fourier Transform (FFT) was invented to find the Fourier Transform. This paper compares three architectures, the basic architecture/ non-reduced architecture of FFT, decomposed FFT architecture without retiming and decomposed FFT architecture with retiming. In each case, the adder used will be Ripple Carry Adder (RCA) and Carry Save Adder (CSA). A fast Fourier transform (FFT) calculates the discrete Fourier transform (DFT) or the inverse (IDFT) of a sequence. Fourier analysis transforms a signal from time to frequency domain or vice versa. One of the most burgeoning use of FFT is in Orthogonal Frequency Division Multiplex (OFDM) used by most cell phones, followed by the use in image processing. The synthesis has been carried out on Xilinx ISE Design Suite 14.7. There is a decrease in delay of 0.824% in Ripple Carry Adder and 6.869% in Carry Save Adder, further the reduced architecture for both the RCA and CSA architectures shows significant area optimization (approximately 20%) from the non-reduced counterparts of the FFT implementation.


Geophysics ◽  
1993 ◽  
Vol 58 (11) ◽  
pp. 1707-1709
Author(s):  
Michael J. Reed ◽  
Hung V. Nguyen ◽  
Ronald E. Chambers

The Fourier transform and its computationally efficient discrete implementation, the fast Fourier transform (FFT), are omnipresent in geophysical processing. While a general implementation of the discrete Fourier transform (DFT) will take on the order [Formula: see text] operations to compute the transform of an N point sequence, the FFT algorithm accomplishes the DFT with an operation count proportional to [Formula: see text] When a large percentage of the output coefficients of the transform are not desired, or a majority of the inputs to the transform are zero, it is possible to further reduce the computation required to perform the DFT. Here, we review one possible approach to accomplishing this reduction and indicate its application to phase‐shift migration.


Geophysics ◽  
1994 ◽  
Vol 59 (7) ◽  
pp. 1150-1155 ◽  
Author(s):  
N. L. Mohan ◽  
L. Anand Babu

In recent years the application of the Hartley transform, originally introduced by Hartley (1942), has gained importance in seismic signal processing and interpretation (Saatcilar et al., 1990, 1992). The Hartley transform is similar to the Fourier transform but is computationally much faster than even the fast Fourier transform (Bracewell, 1983; Bracewell et al., 1986; Sorensen et al., 1985; Pei and Wu, 1985; Duhamel and Vetterli, 1987; Zhou, 1992). Surprisingly, we have not seen a clear definition of the 2-D Hartley transform in the published literature.


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