The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 28, 1989
Filed:
Nov. 06, 1987
David E Lake, Jr, Penn Valley, CA (US);
The Grass Valley Group, Inc., Grass Valley, CA (US);
Abstract
The central difference along a selected axis through a point (u, v) of a rectangularly-sampled luminance field and at an arbitrary angle .alpha. is computed by interpolation. The octant in which the selected axis lies is identified, and first and second pixels through which the lines that limit the identified octant are identified. The first and second pixels are adjacent each other in the luminance field array and lie on a common ordinate or a common abscissa. The difference between the luminance values of the first and second pixels is calculated. Third and fourth pixels, which are symmetrically disposed with respect to the first and second pixels respectively about the point (u, v), are identified, and the difference in luminance values of the third and fourth pixels is calculated. The central difference along the selected axis is calculated by applying the MIX operator to the two difference values and a mix ratio coefficient which is the tangent of an angle which is related to .alpha. and multiplying the result by a factor proportional to the cosine of that angle.