Spectral scanning tunneling microscopy

Spectral analysis, which is a standard technique for detection and quantification of orientation and/or periodicity of images, has been used for the characterization of pore orientation on gray level images [16]. This technique has been mainly applied to characterize the surface structure studied by scanning tunneling microscopy (STM) and atomic force microscopy (AFM) [16]. This method is based on the calculation of the Fourier power spectra, defined in the frequency or k space, as S(k) = F( k) /1 k, where F(k)Fourier coefficients of the image. The... 

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