Patents by Inventor Friedrich Drees

Friedrich Drees has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5365348
    Abstract: In a process for printing a halftone image a plurality of image data describing the halftone step of a halftone dot of a model image are taken over in processing frames. Color step values which determine color gradations of color dots and can be outputted optionally at print positions of a printing screen are obtained from the image data contained in the processing frames. To produce a reproduction image with a large number of halftone steps and, at the same time, a high local resolution in the region of contrast jumps of the model image, a color step value is obtained from each image datum by assigning a color step value existing in the reference pattern associated with the halftone step according to the halftone step described by the image datum and its position in the processing frame.
    Type: Grant
    Filed: April 8, 1993
    Date of Patent: November 15, 1994
    Assignee: Mannesmann Aktiengesellschaft
    Inventors: Friedrich Drees, Raimund Nisius, Hartmut Grethen, Wolfgang Pekruhn