i.ifft(1grass) | GRASS GIS User's Manual | i.ifft(1grass) |
i.ifft - Inverse Fast Fourier Transform (IFFT) for image processing.
imagery, transformation, Fast Fourier Transform
i.ifft
i.ifft --help
i.ifft real=name imaginary=name
output=name [--overwrite] [--help]
[--verbose] [--quiet] [--ui]
i.ifft is an image processing program based on the algorithm given by Frigo et al. (1998), that converts real and imaginary frequency space images (produced by i.fft) into a normal image.
The current mask is respected when reading the real and imaginary component files; thus, creating a mask is a primary step for selecting the portion of the frequency space data to be included in the inverse transform. The module wxGUI vector digitizer can be used to create masks while viewing the real or imaginary component image. Alternatively r.circle can be used to generate high-, low- and donut filters specifying the DC point as circle/ring center. When i.ifft is executed, it (automatically) uses the same GRASS region definition setting that was used during the original transformation done with i.fft.
i.cca, g.gui.iclass, i.fft, i.pca, r.circle, wxGUI vector digitizer
David Satnik, GIS Laboratory, Central Washington University
Glynn Clements (FFTW support)
Available at: i.ifft source code (history)
Accessed: Sunday Jan 22 07:37:37 2023
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GRASS 8.2.1 |