Title :
Special problems in the estimation of power-law spectra as applied to topographical modeling
Author :
Austin, Richard T. ; England, Anthony W. ; Wakefield, Gregory H.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA
fDate :
7/1/1994 12:00:00 AM
Abstract :
An increasing number of topographical studies find that natural surfaces possess power-law roughness spectra. Power-law spectra introduce unique difficulties in the spectral estimation process. The authors describe how an improper window choice allows leakage that yields a spectral estimate that is insensitive to the spectral slope. In addition, the commonly used Fourier-based spectral estimates have higher variances than other available estimators. Higher variance is particularly problematic when data records are short, as is often the case in remote sensing studies. The authors show that Capon´s spectral estimator has less variance than Fourier-based estimators and measures the spectral slope more accurately. The authors also show how estimates of a 2D roughness spectrum can be obtained from estimates of the 1D spectrum for the isotropic power-law case
Keywords :
geophysical techniques; remote sensing; spectral analysis; topography (Earth); Capon; Capon´s spectral estimator; geodesy; geophysical measurement technique; improper window choice; land surface topography; leakage; natural surface; power-law roughness spectra; power-law spectra; remote sensing; rough surface; topographical model; two dimensional; Fractals; Frequency; Random processes; Remote sensing; Rough surfaces; Surface morphology; Surface roughness; Surface structures; Surface topography; Yield estimation;
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on