Transmission resonance and color generation of metal- dielectric subwavelength gratings in visible regions

Metal-dielectric subwavelength gratings under s-polarized and p-polarized visible radiation are studied for discovering their intriguing behaviors of spectral resonance and color property.The dependence of their resonance and color on grating parameters as well as angle of incidence and position of plane of incidence is also analyzed.For s-polarized light,the behavior of spectral resonance with single peak and higher peak efficiency is found.While transmission spectra for p-polarized light are not able to achieve a behavior like that of s-polarization,creating a perceived color is feasible.Moreover,a security grating with distinctive color shifts has been designed and its resonant properties as well as related color variation have also been provided.     

聚集态网点阈值矩阵生成方法及潜在应用研究

目的对聚集态网点阈值矩阵的动态生成方法与算法,及潜在的应用问题进行分析与探讨。方法依据网点网格坐标系,建立网点函数阈值矩阵的生成方法以及网点灰度阈值矩阵的阈值动态分布原则,并得到网格内元素的阈值映射关系式。结果网格内元素的排布顺序越大,网格内获得的阈值就越大,通过对网点函数进行特殊处理,可使网点阈值矩阵的数据中心点相对于网格中心产生一定的偏移,形成具有特殊加网效果的阈值矩阵。结论在不影响图像外观的情况下,通过在网点函数中引入特殊的位相变化信息,加网时就能在图像预定区域生成含有特殊位相编码信息的网点分布,可为图像特定区域植入预期的有意义的编码信息,在图像复制、信息隐藏和印刷防伪等领域具有实际指导意义。     

彩印中玫瑰斑形态转换方法的研究

研究了印刷时不同网点色版叠合形成玫瑰斑的形态控制问题,探讨了形成玫瑰斑的条件及周期性变化的规律,获得了通过对色版进行水平位置的调整来精确控制所形成玫瑰斑形态的方法。研究表明,加网线数相同且加网角度差为30毅是网点重叠形成玫瑰斑的必要条件;将色版沿其加网角度方向平移半个网点周期,可实现空心和中心点玫瑰斑的相互转换;所获得的玫瑰斑形态转换方法中,色版的调整方向由沿加网角度方向转换为沿水平或垂直的变化,可实现对玫瑰斑形态的精确控制。