The hybrid screen leverages two halftoning techniques, screening and direct binary search (DBS), to achieve the better quality of the halftoned images, and to enable the algorithm to be integrated into low-cost printers with limited computational resources. This work proposes a complete hybrid screen design method for multilevel output with unequal resolution printing pixels in a laser electrophotographic system. Because of the unstable rendering output of the electrophotographic process, we adopt a clustered- dot screen in our work. We also use the supercell approach to solve the trade-off between screen frequency and the effective number of quantization levels that is inherent to a cluster-dot screen. Moreover, we use subpixel modeling to simulate the unequal resolution printing pixels and multilevel output. This method is well-suited to development of halftoning algorithms for systems with unequal resolution. We also explore several design rules to evaluate the impact on printing quality.
Wan-Eih Huang, Tongyang Liu, Kurt Bengtson, Jan Allebach, "Monochrome hybrid, multilevel, halftone screen with unequal spatial resolution for a low-cost electrophotographic printer" in Proc. IS&T Int’l. Symp. on Electronic Imaging: Color Imaging XXIII: Displaying, Processing, Hardcopy, and Applications, 2018, pp 428-1 - 428-5, https://doi.org/10.2352/ISSN.2470-1173.2018.16.COLOR-428