Apply a median filter of the specified width on each column individually. Deconstruct the two dimensional image into a one dimensional time series vector in which each element represents an equal time interval. Trim the time series vector to a power of two for faster FFT processing. Compute the FFT of the time series vector. Plot the power spectrum versus frequency.
Power is computed as the square of the magnitude of the complex transform.
And for each amp of an image it produces output like figure 1. The Johns Hopkins University . All rights reserved.