针对数字全息再现像质量差的问题，对数字全息再现光强度进行了分析，介绍了光强相减法和中值滤波方法的原理，提出了用中值滤波和光强相减法改善数字全息再现像质量的设想。光强相减法就是对全息图用HRON相减处理消除零级像和背景光。中值滤波处理能有效地减少背景噪声光。实验对比全息图的直接再现像、HRO相减处理后的再现像、光强相减法处理后的再现像和中值滤波与光强相减法共同处理后的再现像，表明本方法有效地提高了再现像质量。

Aiming at improving the quality of reconstructed images of digital holography, based on the analysis of the reconstruction light intensity of digital hologram, a method combining light intensity subtraction and median filtering is proposed. The principles of light intensity subtraction and median filtering are described. Light intensity subtraction based on HRON substraction diminishes the zero-order image and background light. The median filter process effectively minimizes the background noise light. From the comparison of quality of experimentally reconstructed images obtained by different methods, it is shown that the proposed method could effectively improve the quality of reconstructed image of digital hologram.