为提高印刷品的防伪性能，从数字印刷的角度，结合数字图像处理技术，研究了基于数字加网的半色调图像的防伪印刷技术，以及不受扫描误差影响的直接检测技术。在前人研究的基础上，提出了一种利用噪声平衡误差扩散技术在彩色的半色调图像中加入水印的方法，并且直接检测了防伪效果。结果表明，只有在对应的解码图片叠加在含有隐藏信息的彩色图像上时，才可以观察到彩色图像的隐藏信息，说明该防伪方法在加网复制印刷中具有较好的防伪效果。

Anti-counterfeit printing technology of halftone images based on digital screening and direct detection technology not influenced by scanning error were studied from the perspective of digital printing and combining with digital image processing technology. A reasonable method to embed data in color halftone images with noise-balanced error diffusion (NBEDF) and directly detect the anti-counterfeit effects was proposed based on previous researches. The experimental results showed that hidden information can only be observed when the corresponding decoded image overlays the color image with hidden information. It was concluded that the anti-counterfeit method has good anti-counterfeit effect in screening print.