零频分量在离轴全息图中分布广且不携带物体的相位信息, 该分量的存在会显著降低全息图的信噪比从而影响重建精度。现有的零频分量抑制方法需要记录多张全息图或手动调节全息图的小波分解层数才能达到最佳效果, 虽然拉普拉斯算子也可用于抑制零频分量, 但难以提取+1级像。为了克服这些问题, 提出了一种基于希尔伯特-黄变换的零频抑制方法, 只需记录一张全息图且避免了手动调整分解层数。为了验证所提出方法的有效性, 将所提出方法处理后的全息图频谱与未零频抑制的全息图频谱、采用Haar小波变换和采用Laplace算子处理后的全息图频谱进行了对比, 还比较了三个随机选取的对比区域的标准偏差和截面图。实验结果表明所提出的方法不仅可以有效地抑制零频分量并且性能优于其他两种方法。

The zero-frequency component (ZFC) distributes widely and carries no phase information of the object in off-axis hologram, which significantly reduces the signal-to-noise ratio and thus decreases the accuracy of the reconstruction result. To suppress ZFC, existing methods need record multiple holograms or suffer from manually adjustment of hologram decomposition layer to achieve optimal results. Laplace operator is also used to suppress ZFC but it is difficult to extract the +1 level. To overcome these problems, a Hilbert-Huang transform based method is proposed that only needs one hologram and avoids manually adjusting the layer of decomposition. To verify the effectiveness of the proposed method, the frequency spectrum of the hologram processed by the proposed method is compared with the frequency spectrum of the hologram without ZFC suppression, the hologram suppressed with Haar wavelet transform and Laplace operator. Three regions in the corrected phase maps of the holograms are randomly selected to obtain the standard deviations and sectional diagram. The experimental results show that the proposed method can effectively suppress the ZFC and performs better than other two methods.