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:
Jul. 10, 1990
Filed:
Oct. 06, 1988
Alastair Reed, Bedfordshire, GB;
Crosfield Electronics, London, GB;
Abstract
A method and apparatus for processing a first (e.g. half-tone) image constituted by a second (e.g. continuous tone) image convolved with a periodic (screen) function, to produce the second image is described. The invention is particularly suited to handling digitally represented half-tone images. The apparatus comprises a microcomputer (17) for determining digital data defining a frequency filter characteristic adapted to suppress the frequency or frequencies of the periodic function. A fast Fourier transform circuit (11) transforms the image data into the frequency domain and a multiplier (12) multiplies the transformed data by the frequency characteristic stored in a store (13). The resultant multiplied data is inversely transformed back into the image of spatial domain by a fast Fourier transform circuit (14) to generate the second image.