df_dft

Simple command line to dft/idft images.

Usage: DFT <dft|idft> <source file> <dest file>

when you dft an image, the source file is an image file. It turns it to greyscale, and then generates the following files:

• .raw.png - this is the greyscale image given to dft.
• .mag.png - this shows the magnitude data of the dft. it is put through a log function and normalized to have the largest value of 1.0
• .phase.png - this shows the phase information. -pi to +pi is mapped to 0 to 1.
• .dft - this is a binary file that has uint32 width and height, then w x h x 2 doubles for the dft data.
• .csv - this has the raw dft data as well as the magnitude and phase data, in a csv format.

When you idft an image, the source file is a .idft file made via the dft command. it will then do an inverse dft and spit out the results.

This utility uses:

• simple_fft to do dft and idft operations: https://github.com/d1vanov/Simple-FFT
• stb to read and write images: https://github.com/nothings/stb

Example: LokiAlan

DFT dft assets/LokiAlan.jpg out/LokiAlan

Frequency Magnitudes:

Frequency Phases:

DFT idft out/LokiAlan.dft out/LokiAlanRT

Example: BlueNoise

DFT dft assets/BlueNoise.png out/BlueNoise

Frequency Magnitudes:

Frequency Phases:

DFT idft out/BlueNoise.dft out/BlueNoiseRT