TERRAIN SEASCAPE IMAGE GENERATOR WITH MATH MODEL DATA BASE

摘要

TERRAIN/SEASCAPE IMAGE GENERATOR WITH MATH MODEL DATA BASE A technique for the real-time computer generation of visual scenes of rolling terrain and sea waves is based on a view ray approach wherein an azimuth sweep is defined and an image profile is generated by incrementing range steps from the view point but employs a data base which is an on-line math model consisting of a summation of cosine functions rather than a grid data base. Math models are generated separately for both land and sea elevation posts for the scene to be generated. A horizontal field of view is defined as a predetermined number of increments between sweeps perpendicular to a boresight from a view point, and a vertical field of view is defined as a predetermined number of increments between view rays perpendicular to the boresight from the view point. The change in range is incremented along the boresight from the view point, and for each range increment, the view ray is stepped down by an increment corresponding to an increment change in the tangent of the view angle. An elevation value of the view ray is accumulated for each incremented change in the tangent of the view angle. For each range increment, the math model forthe land elevation posts is compared with the math model for the seal elevation posts, and the larger of the two is selected. At each range increment, the accumulated elevation value of the view ray is compared with the selected math model of elevation posts and, if a view ray strikes the selected elevation post, the data for that post is read to a display; otherwise, the math models of the land and sea elevation posts are incremented.