Figure 1.
Reconstruction of the retinal input. A, Head rotations were expressed by the Fick angles (yaw Φz, pitch Φy, and roll Φx) necessary to align a reference frame, H° = {hx°, hy°, hz°}, established during an initial calibration procedure with a head-fixed frame, H = {hx, hy, hh}. Eye movements, defined as eye-in-the-head rotations, were measured by the horizontal and vertical rotations, αH and αV, necessary to align H with an eye-centered reference frame E, oriented so that its first basis vector ex coincided with the line of sight. B, Joint measurement of the orientation and position of the head enabled localization of the centers of rotations of the two eyes (C) and their optical axes (ex). The retinal image was estimated by placing the eye model of Gullstrand (1924) at the current eye location. N1 and N2 optical nodal points, T target, P target's projection on the retina.