Title :
Unscreening using a hybrid filtering approach
Author_Institution :
Xerox Webster Res. Center, NY, USA
Abstract :
This paper presents a method for retrieving a gray picture from a halftone image. The algorithm performs a two dimensional (2-D) filtering which is composed of a 1-D lowpass filtering in one direction and a 1-D pattern matching in a perpendicular direction. It provides substantially better detail than the traditional lowpass filtering approach, yet it is robust to noise and distortions. The technique can be applied to both orthographical halftones and scanned halftones
Keywords :
filtering theory; image matching; image processing; low-pass filters; pattern matching; two-dimensional digital filters; 1D lowpass filtering; 1D pattern matching; 2D filtering; gray picture retrieval; halftone image; hybrid filtering approach; orthographical halftones; scanned halftones; two dimensional filtering; unscreening; Computer errors; Constraint optimization; Filtering algorithms; Frequency; Image recognition; Image retrieval; Matched filters; Noise robustness; Pattern matching; Pattern recognition;
Conference_Titel :
Image Processing, 1996. Proceedings., International Conference on
Conference_Location :
Lausanne
Print_ISBN :
0-7803-3259-8
DOI :
10.1109/ICIP.1996.560503
