Object structure effect on optimal levels of hologram binarization in terms of reconstructed image quality

Abstract

Subject of Research. The paper presents research results on object structure effect, that is the type and size of its elements, on optimal level of computer generated Fresnel holograms binarization in terms of reconstructed image quality. Method. The study was carried out through mathematical modeling of synthesis and reconstruction of holograms of various objects with 80x80 nm pixel size using different binarization levels, and comparing the quality of reconstructed images. All numerical experiments were carried out in a software package for the synthesis and reconstruction of holograms using the following hologram synthesis and reconstruction parameters: wavelength equal to 13.5 nm, hologram pixel size equal to 20x20 nm, distance between object and hologram planes of 20.3 μm, reference beam angle of 18.1. A criterion for the quality estimation of reconstructed image was a number of gradations in the threshold processing of this image, in which the intensity distribution in the reconstructed image would be identical to the intensity distribution in the original object. Main Results. The dependency graphs between binarization level and thenumber of permissible gradations for threshold image processing are obtained. For binary transparency objects used in the research, they are curves with two pronounced peaks, usually located at levels 0.2 and 0.34 along binarization axis.The object structure has an effect on specific value of optimal binarization level and on the maximum number of threshold processing gradations; the general nature of researched dependency remains unchanged even for complex transparency objects. Practical Relevance. The revealed dependency gives the possibility to accelerate the optimal level choice of synthesized holograms binarization.