Author(s)

Zhao Li

Corresponding Author

Zhao Li

ABSTRACT

Natural images can fundamentally affect the evolution and development of biological visual systems. Therefore much research has been done on the statistics of natural images. One of the most striking findings is that the orientation averaged power spectrum of natural images follows the universal power law. However little is known the origin of the universal power law. In this paper, the power spectra of natural images were explored under different transforms. We found that the power spectrum was unaffected under histogram equalization transform and a shape transform. However, with a little surprise, it found that the power spectra were affected more by local micro structure than global configure structures. Then a three dimensional and a two dimensional simulations were carried out. The results of the simulations indicated that the universal power law may due to the projection of three dimensional objects with sizes equally distributed. However, the size distribution of two dimensional objects waits further research.

KEYWORDS

Natural image, Power spectrum, Universal power law, Simulation, Random.