在对3维粒子场全息图的数值重构过程中,为了提高和改善聚焦粒子再现像的对比度,减小直透光、孪生像以及离焦粒子像的影响,采用了1种数值处理方法,通过对数值重构出的2个聚焦与非聚焦面上粒子复振幅相减,可以将直透光、孪生像和离焦粒子像对聚焦粒子的影响同时减小,并给出了简要理论以及仿真、实验结果。结果表明,在同轴数字全息层析再现粒子场过程中,该方法适用于在某一聚焦面仅显示聚焦粒子; 此外,该过程仅需要一张全息图,而且不需要对全息图做预前和后期处理。

In order to improve the contrast of a reconstructed image and reduce the effect of directly transmitted light,conjugate image and defocused image on the focused image of the particle in the reconstruction of a 3-D particle digital holography,a numerical method was proposed in which the above effect can be reduced because of the subtraction of both the complex amplitudes of the particle in the focused and defocused planes.The theory of the method was presented.The simulated results and experimental examples were shown.This method is useful to slice in-line digital holograms to display only in-focus particles at a focused plane.Furthermore,in the reconstruction process,only a single hologram is needed without additional pre- or post- processing.