Perspective projection calculation devices and methods

Abstract

A perspective projection calculation device making a perspective correction accurately and rapidly in each plane while avoiding an increase in the number of dividing operations. The perspective projection calculation device comprises at least one plane slope element coefficient calculation unit for calculating a coefficient which implies a plane slope element of the triangle defined in the three-dimensional space usable in common in a plurality of geometrical parameters to be interpolated, at least on interpolation coefficient calculation unit for calculating an interpolation coefficient from the plane slope element coefficient calculated by the plane slope element coefficient calculation unit, and at least one correction unit for making a perspective correction, using the interpolation coefficient obtained in the interpolation coefficient calculation unit.

What is claimed is:  
     
         1 . A perspective projection calculation device in an image processor for perspectively projecting a triangle defined in a three-dimensional space onto a two-dimensional space and for shading the triangle in the second-dimensional space, comprising: 
 at least one plane slope element coefficient calculating means for calculating a coefficient which implies a plane slope element of the triangle defined in the three-dimensional space;    at least on interpolation coefficient calculating means for calculating an interpolation coefficient from the plane slope element coefficient calculated by the plane slope element coefficient calculating means; and    at least one correcting means for making a perspective correction, using the interpolation coefficient.