How to calculate spatial frequency of an image just in one direction? FFT spectra is not what is needed; what I need is a histogram showing which frequencies are there in image in horizontal direction, and which one is dominant
Such spatial frequency is usually known for a sinusoidal grating; I need the same property for grayscale raster image (in cycles per pixel)
You can take a 1D Fourier transform of a row of pixels from the image; it will give you the horizontal frequencies present in that row.
You could sample one row out of the image, or else average all the rows together to get an overall picture of the horizontal frequencies.