When a projector is oblique with respect to a planar display surface, it creates keystoning and the projected image is distorted. We present a rendering technique to display perspectively correct images for a moving user. This allows using roughly aligned projectors and eliminates the need for frequent electro-mechanical adjustments. The rendering process has no additional cost and can be imple...

I and II where k $ Oor n $ 2 are the similitudes. For by (17), Y' = i renders H infinite. Then by the last of equations (13), the pre-images of the minimal lines Y' = =i must make H infinite. But we know by (17) that y' = i are infinite roots of H. Thus the minimal lines y' must be converted into the minimal lines Y' = =i by the collineation (2) (unless the field of force has constant slope =4:...

Let C: L L be a projective deformation of the second order of two totally pn focal pseudocongruences L and L of (m-l)-planes in projective spaces and n, 2m-i < n < 3m-l, and let K be a collineation realizing such a C. The deformation C is said to be weakly singular, singular, or a-strongly singular, s 3,4,..., if the collineation K gives projective deformations of order i, 2 or of all correspon...

The problem of nding the collineation between two 3-D projective reconstructions has been proved to be useful for a variety of tasks such as calibration of a stereo rig and 3-D a ne and/or Euclidean reconstruction. Moreover such a collineation may well be viewed as a point transfer method between two image pairs with applications to visually guided robot control. In spite of this potential, met...

‎let $m^n$ be an $n(ngeq 3)$-dimensional complete connected and‎ ‎oriented spacelike hypersurface in a de sitter space or an anti-de‎ ‎sitter space‎, ‎$s$ and $k$ be the squared norm of the second‎ ‎fundamental form and gauss-kronecker curvature of $m^n$‎. ‎if $s$ or‎ ‎$k$ is constant‎, ‎nonzero and $m^n$ has two distinct principal‎ ‎curvatures one of which is simple‎, ‎we obtain some‎ ‎charact...