An image processing apparatus for outputting an image which contains different kinds of multi-level signals for letters, figures, photographs, screened-halftone, etc. The apparatus comprises a screened-halftone pattern detecting circuit and a continuous-tone pattern detecting circuit for detecting a...http://www.google.fr/patents/US5361142?utm_source=gb-gplus-shareBrevet US5361142 - Image processing apparatus and method for multi-level image signal
Image processing apparatus and method for multi-level image signal
