Zero Order Correction of Shift-multiplexed Computer Generated Fourier Holograms Recorded in Incoherent Projection Scheme

Application of computer holography methods provides the possibility to obtain the high quality holograms of objects that exist as digital models without the necessity of complex and high precision optical schemes. Computer generated Fourier holograms (CGFH) are widely used for record and optical restoration of relatively simple 2D raster objects. Application of incoherent photolithography methods such as incoherent projection allows the record of CGFHs as micro-holograms onto the photosensitiv medium with desired reduction of hologram sizes using relatively simple optical setup. The reconstruction optical schemes of CGFHs can be implemented in augmented reality displays and optical sight indicators. In this article the specificity of CGFH shift-multiplexed record process and particularly the method of zero order correction is discussed. Keywords: computer generated hologram, Fourier hologram, incoherent projection scheme

Objects Reconstruction By Compressive Sensing from Single-pixel Registrations Using DMD

Compressive sensing allows to reconstruct information from a number of sparse signals. Use of digital micromirror device (DMD) between object and single-pixel detector planes is example of sparse signals registration technique. Detection of illumination from the objects by a single-pixel detector using a DMD was modeled. Grayscale, binary and color object images were used as objects. By compressed sensing images obtained under various recording conditions were reconstructed. Obtained results were analyzed. Reconstruction quality estimations and processing times are given. Keywords: compressed sensing, single-pixel imaging, digital micromirror device, image quality

Coefficients Quantization at Off-axis Digital Hologram Wavelet Compression

Digital holographic information is compressed for storage of 2D- or 3D-objects amplitude and phase distributions, fast transmission, analyzing and displaying of these data. In this paper features of application of wavelet transforms for off-axis digital holograms compression are considered. The combined technique based on zero and twin orders elimination, wavelet compression of the amplitude and phase components of obtained Fourier spectrum and further additional compression of wavelet coefficients by thresholding and quantization is analyzed. Numerical experiments on reconstruction of images from the compressed holograms are performed. The comparative analysis of applicability of various wavelets and additional quantization of coefficients is performed. Obtained results demonstrate possibility of 180 and more times compression using iterative and noniterative methods of coefficients quantization and threshold zeroing less 80% of wavelet coefficients. Keywords: digital holography, hologram compression, wavelets, quantization, thresholding, digital image processing