Patent ID: 7233695

Claim:
A method for computing the function value of an input node based on function values of known nodes within a mixed raster content, where mixed input images, some or all of which may be sub-sampled, are merged according to a given rule, to form an output image, the method comprising the operations for each input image individually, and comprising the steps of: (a) forming a database of known nodes and corresponding known node function values, the known nodes being non-uniformly located such that a distance between any two adjacent known nodes is an integer power-of-two number; (b) searching from the database of known nodes for a first node such that the input node is located between the first node and a second node adjacent to the first node, the first and second nodes having a first node function value and a second node function value, respectively; (c) computing the difference δ between the input node and the first node; (d) shifting δ to the right by k positions, k being the logarithm in base 2 of the distance between the first node and the second node; and (e) computing the function value of the input node by combining the first node function value with the product of the shifted δ and the difference between the second node function value and the first node function value.