Method, arrangement, computer program and computer readable storage medium for scaling two-dimensional structures

摘要

A method for scaling two-dimensional structures, which is especially usable for resizing digital 2D images with a rational scaling factor, is based on efficient implementation of a diamond-shaped filter. The conventional “1”-diamond matrices of variable size are replaced by a (m×n) coefficient matrix. For any given rational scaling factor, the computational load for calculating an output pixel is reduced to filtering (m×n) input pixels with a corresponding (m×n) filter matrix. The coefficients of this filter matrix depend from the phase of the output pixel to be calculated and the factor of interpolation, but are always integer numbers. The coefficients may be stored in lookup tables (LUT), which leads to a very efficient implementation of the inventive method. In one embodiment, a (3×3) coefficient matrix has been found to be advantageous.

主权项

1. A method for scaling two-dimensional structures with a scaling factor, wherein a source structure is transformed into a target structure and the source and target structure are each constructed from regularly arranged structure elements, the method comprising:
defining a first scheme comprising structure elements Pij associated with the source structure and arranged in m rows and n columns, subdividing at least a portion of the structure elements Pij of the first scheme into sub-structure elements arranged in p rows and q columns, with each row and each column having a corresponding sub-structure element PSkl, defining a second scheme PD comprising a subset of the sub-structure elements PSkl, and at least one distinguished sub-structure element PD*, superposing the first scheme with the second scheme PD so as to overlap the at least one distinguished sub-structure element PD* step-by-step with at least a portion of the sub-structure elements PSkl of the first scheme, for each step of superposing, constructing a coefficient matrix Hkladapt having a dimension that is independent of the scaling factor and that is assigned to the sub-structure element PSkl of the first scheme, with which the distinguished sub-structure element PD* is overlapped, wherein the coefficients hklij of the coefficient matrix Hkladapt define a weight of the structure element Pij of the i-th row and j-th column of the first scheme, and defining a structure element of the target structure by evaluating at least a portion of the structure elements Pij of the first scheme and at least a portion of the matrices Hkladapt.