Selective Visual Attention: Computational Models and Applications

4.3 Phase Fourier Transform Approach

4.3.1 Introduction to the Phase Fourier Transform

The SR model gives us an elicitation that may not need to completely simulate the structure of the visual system for finding the salient objects in a scene. Existing computational means used in many engineering areas probably also help us to solve the pre-attention issue. However, although the SR model can obtain good results, the reason is not clear, because we are not sure whether the unsmooth parts (spectral residua) in the amplitude spectrum can indeed reflect the innovative part or the salient objects in the scene. Figure 4.5(a) and (b) shows two images with a size of 120 × 120 pixels. They have the same background, but no person (or salient object) exists in one of them, and in the other picture, a person (Polynesian) appears in the foreground. The one-dimensional log amplitude spectra, averaging the frequency components of all pixels at the same distance (number of pixels) from the original point to the pixel, are shown in Figure 4.5(c) and (d).

Figure 4.5 Comparison of two amplitude spectra of the scenes without a person and with a person: (a) background picture (original image); (b) the picture with a person; (c) one-dimensional log amplitude spectrum for 4.5(a), i.e., vs. frequency (number of pixels from original point); (d) one-dimensional log amplitude spectrum for 4.5(b)

Obviously, ...