Patent ID: 8031373

Claim:
A method for screening the continuous-tone original to form its halftone copy by transformation of an input two-dimensional signal (E i,k ) of tone of an original, this signal comprising the multilevel tone values of an original areas and presented in the matrix ([E i,k ], m,n ) of m×n areas, into a two-dimensional signal (E hftn i,k ) of a halftone copy, the input two-dimensional signal comprising the bi-level tone values of printing and non-printing elements and presented in the matrix ([E hftn i,k ] m,n ) of m×n elements, the method performed by a halftone processor included in a reproducing device, the halftone processor includes a halftone copy signal former, a first weight values distributor, a second weight values distributor, a contour trace signal generator, and a segments signal forming unit, comprising: forming, by the halftone copy signal former, the two-dimensional signals (E wght 1 , E wght 2 ) of weight values distributions, these values belonging to the variety of said tone values and making up the weight value matrixes ([E wght 1 i,k ] m,n , [E wght 2 i,k ] m,n ), which dimensionally correspond to matrixes of said areas and elements; distributing, by the first weight values distributor, the values (E wght 1 ) within the elements of the first of said weight matrixes without taking into account the tone variation over an original character and distributing, by the second weight values distributor, the values (E wght 2 ) within the second of said weight matrixes in dependence with contour or fine detail geometry on an original; forming, by the halftone copy signal former, the two-dimensional signal (E hftn i,k ) of a halftone copy, its bi-level values ascertained as result of comparison of the first ([E wght 1 i,k ] m,n ) or of the second ([E wght 2 i,k ] m,n ) weight matrixes with the matrix ([E i,k ] m,n ) of tone values of an original; and forming the halftone copy on a substrate dark or light by the reproducing device in accordance with the formed two-dimensional signal, wherein, the method further comprising: placing the part of weight values of said second matrix within the spatial intervals -segments; ascertaining, by the contour trace signal generator, the location of said segments by means of forming the contour trace signal E trace i,k as a matrix [E trace i,k ] m,n dimensionally corresponding to weight matrixes and comprising the informative, indicating the contour position, signal values for this matrix elements, corresponding to original areas containing a contour, and comprising the non-informative signal values for the rest elements of contour trace signal matrix; and ascertaining, by the segments signal forming unit, the position of boundaries of said segments dependant on the number of adjacent elements used for the contour or fine detail reproduction on a halftone copy of an original.