Byong-Won Hwang Tae-Ha Kang Tae-Seung Lee Improved Edge Enhanced Error Diffusion Based on First-Order Gradient Shaping Filter. 473-482 http://dx.doi.org/10.1007/978-3-540-24677-0_49 2004 conf/ieaaie/2004 IEA/AIE db/conf/ieaaie/ieaaie2004.html#HwangKL04