离轴数字全息零级像和共轭像的消除方法

为了提高离轴数字全息图的再现像质量,提出了一种消除离轴数字全息零级像和共轭像的方法。该方法通过对参考光进行一次π相移、记录两幅全息图,对两幅全息图作差后进行傅里叶变换,结合频谱滤波的方法用矩形窗函数从中滤出包含有物光波频率成分的频谱,然后对其进行数字再现。结果表明,在零级像和±1级像有重叠的情况下,该方法能有效地消除零级像和共轭像的干扰,有效提高再现像质量。

Elimination method of zero-order image and conjugate image of off-axis digital hologram

In order to improve the reconstructed image quality of off-axis digital hologram, an elimination method of zero-order image and conjugate image of off-axis digital hologram was presented. Based on reference light with a π phase shift and recording two holograms, Fourier transform was made for two subtracted holograms. Combined with spectral filtering method, the associated spatial frequencies was filtered out with rectangular window function. Then digital reconstruction was made. Experiments show that the method can eliminate the zero-order image and conjugate image even in the case that the zero-order image and others images overlap seriously, so the method can effectively improve the quality of reconstructed image in digital holography.