Fig 3. The upper panel illustrates the support vector machine (SVM) classification sequence for a representative mutilation and paired neutral image.

First, one half of the original images were subjected to a two-dimensional fast Fourier transformation (2-D FFT). Phase spectra were discarded and the SVM was trained with 80 amplitude-only features per image (20 spatial frequencies, four orientations). After training, the SVM was tested on the remaining half of the images. The lower panel illustrates the averaged spectral contour plots of our intact mutilation, disgust, and neutral images. The inner contour represents 60% and the outer contours 80 and 90%, respectively, of image energy.