I'm not too familiar with image processing, so I need a little help: In general, if we transform a discrete function $f$ with $n$-variables from the "spatial domain" using the Fourier transformation, then there are also $n$-variables (frequencies) in the "frequency domain". So an image, which appears obviously 2D ($xy$-plane) leads then into a 2D contour plot if one plots the amplitude and phase spectrum.
I found an interesting work [1] about saliency maps, where the authors used "orientation averaged curves of $\log$ spectra":
Is someone fimiliar with this terminology? Is this just the averaging of row entries for each column?
I found nowhere else this 1D representation of an actual 2D plot.
Best regards, Albert
Reference
[1] X. Hou and L. Zhang, "Saliency Detection: A Spectral Residual Approach", 2007 IEEE Conference on Computer Vision and Pattern Recognition, Minneapolis, MN, USA, 2007, pp. 1-8, doi: 10.1109/CVPR.2007.383267.
