An Inverse Halftoning Technique Using Modified Look-Up Tables
Fundamenta Informaticae
Neural network based method for image halftoning and inverse halftoning
Expert Systems with Applications: An International Journal
Halftone image resampling by interpolation and error-diffusion
Proceedings of the 2nd international conference on Ubiquitous information management and communication
Fast codebook search algorithm for vector quantization using sorting technique
Proceedings of the International Conference on Advances in Computing, Communication and Control
Speed up of the edge-based inverse halftoning algorithm using a finite state machine model approach
Computers & Mathematics with Applications
Iterated conditional modes for inverse dithering
Signal Processing
A new inverse halftoning method using reversible data hiding for halftone images
EURASIP Journal on Advances in Signal Processing
An Inverse Halftoning Technique Using Modified Look-Up Tables
Fundamenta Informaticae
| Hi-index | 0.02 |
The objective of this work is to reconstruct high quality gray-level images from bilevel halftone images. We develop optimal inverse halftoning methods for several commonly used halftone techniques, which include dispersed-dot ordered dither, clustered-dot ordered dither, and error diffusion. At first, the least-mean-square (LMS) adaptive filtering algorithm is applied in the training of inverse halftone filters. The resultant optimal mask shapes are significantly different for various halftone techniques, and these mask shapes are also quite different from the square shape that was frequently used in the literature. In the next step, we further reduce the computational complexity by using lookup tables designed by the minimum mean square error (MMSE) method. The optimal masks obtained from the LMS method are used as the default filter masks. Finally, we propose the hybrid LMS-MMSE inverse halftone algorithm. It normally uses the MMSE table lookup method for its fast speed. When an empty cell is referred, the LMS method is used to reconstruct the gray-level value. Consequently, the hybrid method has the advantages of both excellent reconstructed quality and fast speed. In the experiments, the error diffusion yields the best reconstruction quality among all three halftone techniques