修正离轴参考光计算全息图的数值再现及像质评价研究

修正离轴参考光计算全息图制作方法中，博奇、黄氏及李维汉型三种计算全息图实质上是分别在全息图函数中加入新的偏置项，从而形成不同的全息图编码方式.由于这三种编码方式所加的偏置项不同，其对再现像质量的影响也不相同.本文将计算全息技术与数字全息技术相结合，实现了博奇、黄氏及李维汉型三种计算全息图的设计制作、数据处理、再现过程的全数字化.一方面，采用计算机对计算全息图进行数字化滤波，在频谱域消除虚像和零级像，得到了单一的清晰实像；另一方面，通过引入信噪比和图像亮度等参数指标，对以上三种计算全息图的再现像质量进行评价

Numerical reconstruction and image quality evaluation of modified off-axis reference beam computer generated holograms

The coding principles of Burch, Huang and Lee type of computer generated holograms (CGH) are to introduce different bias term to the holographic function respectively to generate modified off-axis reference beam CGHs. Because of the introduction of different bias term, there must be some differences in the quality of reconstructed images. In this paper, we accomplished the entire digitization of the whole processes of CGH design, fabrication, data processing and reconstruction by combining computer generated holography and digital holography. On the one hand, by applying digital filtering technique in frequency domain to the processing of CGH, we successfully eliminated virtual image and zero-order image and obtained single clear real image. On the other hand, the merit factors of signal-to-noise (SNR) and brightness were introduced to evaluate the quality of reconstructed images of three CGHs, and it was concluded that the image quality of Huang's CGH was much better than the two others.