Zero-order term suppression in off-axis digital holography by enhanced spectrum based on Kronecker-product image interpolation

Off-axis digital holography can reconstruct the amplitude and phase of the imaging object by selecting the original term spectrum through filtering. A larger filtering range contains more effective information from the original term spectrum. However, the presence of zero-order term limits the size of the filter window and consequently affects the resolution of reconstruction. In this work, we propose an enhanced spectrum method based on Kronecker-product image interpolation to better suppress zero-order term and improve the quality of reconstruction. Additionally, a novel rectangular Butterworth filter is also introduced to make the reconstructed images smoother and more regular. We demonstrate the feasibility of this method through simulations of a picture and experiments with two different imaging objects.