By using independent component analysis,a suppression method for zero-order term is proposed in off-axis digital holography.At first,two different amplitude frames of holograms are captured by a CCD-camera to form an observation signal.Secondly,a twin-image and a zero-order term are separated by means of independent component analysis.Finally,a separated twinimage is subtracted remnants zero-order term,which eliminates the zero-order term effectively.Computer imitating experiments show that this method is better then actual phase-shift method on advantage and validity.

A zero-order term suppression method for digital holography with Hilbert-Huang transform is proposed.Two-dimensional hologram data are changed into one-dimensional data.The first order of intrinsic mode functions containing high frequency of hologram is obtained by Hilbert-Huang transform through empirical mode decomposition.The second order of intrinsic mode functions containing direct current component of hologram is obtained similarly.Experiments show that reconstructed image of the first order of intrinsic mode functions represents conjugate image with suppressed zero-order term,and the second order of intrinsic mode functions represent the zero-order term.The proposed method preserves effectively information of original complex-wave and shows advantage in computational speed since it decomposes empirical mode decomposition once and obtains suppressed zero-order term in space frequency field well.