| The ability to determine point-of-gaze with respect to an observed scene provides significant insight into human cognitive processes, since shifts in gaze position are generally guided by shifts in attentional focus. Using a head-mounted eye tracking system, a methodology based on two or more point correspondences in two views was developed to reconstruct the subject's point-of-gaze. Reconstruction errors of less than 2 pixels can be obtained when the homography algorithm with distortion compensation is used. Analysis of normalization techniques that reduce the sensitivity of this algorithm to input data errors suggests a radially symmetric distribution for the point correspondences. The new methodology was implemented and validated in a clinical study examining the correlation between visual selective attention and mood disorders. In this study, we found that the mean time that depressed subjects spent looking at images with dysphoric themes was significantly larger than that of normal control subjects. |
