Meaning of lines on x- and y-axis of a centered FFT-spectrum of an image

1. What does the Y-axis represent on FFT?
2. What are the X and Y-axis of a Fourier transform?
3. What are FFT lines?
4. What does the FFT of an image represent?

What does the Y-axis represent on FFT?

The FFT display shows frequency based signals as generated from the FFT functions. The x-axis shows the frequency while the y-axis shows the amplitude of the different spectral components.

What are the X and Y-axis of a Fourier transform?

The frequency spectrum is from 0 to fs, where fs is your sampling frequency.So in response to your question the Y-axis is the amplitude (because you took the ABS value of the complex output) and the X-axis is the frequency values from 0 to fs.

What are FFT lines?

The fast Fourier transform (FFT) is a computational algorithm that efficiently implements a mathematical operation called the discrete-time Fourier transform. It transforms time-domain data into the frequency domain by taking apart a signal into sine and cosine waves.

What does the FFT of an image represent?

The FFT decomposes an image into sines and cosines of varying amplitudes and phases, which reveals repeating patterns within the image. Low frequencies represent gradual variations in the image; they contain the most information because they determine the overall shape or pattern in the image.