Comparative analysis of off-axis digital hologram binarization by error diffusion

Abstract

A digital micromirror device (DMD) provides 2D- and 3D-scene reconstruction by displaying diffractive and holographic optical elements. The highest frame rates (tens of thousands of Hz) can be achieved if the displayed optical elements are binarized. Except for DMD applications, hologram binarization is useful for display creation, image encryption, information compression and storage, fast 3D printing, etc. Error diffusion is one of the most qualitative implementations of hologram binarization. In this paper, three group's weighting matrices of error diffusion are analyzed: 16 standard, eight dot and six diagonal matrices. Thus, 30 error diffusion methods were used for optically recorded off-axis digital hologram binarization. The quality of the image reconstruction from the binarized holograms was compared. Direct applications of error diffusion with large weighting matrices and dot diffusion provide the highest reconstruction quality. Seven metrics were used as the error diffusion threshold. Twelve bypass directions of error diffusion were analyzed. In addition, the joint application of Otsu threshold and complex bypass directions allows us to improve the quality of hologram binarization by 15%.

What Binarization Method Is the Best for Amplitude Inline Fresnel Holograms Synthesized for Divergent Beams Using the Direct Search with Random Trajectory Technique?

“…Choosing the optimal binarization method allows the improvement of the method: to reduce synthesis error, increase diffraction efficiency and/or reduce calculation time. Popular and widely used binarization methods are divided into groups: global [ 24 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ] and local [ 46 , 47 , 48 , 49 , 50 , 51 ] thresholding, standard [ 52 , 53 , 54 ] and dot [ 29 , 55 , 56 , 57 ] error diffusion, and iterative techniques [ 58 , 59 ]. In the global thresholding, parameters (global mean and variance) are calculated using all pixel values.…”

“…Thus, already-processed pixels participate in the further propagation of the error value. The methods of Knuth (Kn) [ 55 ], Guo (Guo) [ 56 ], Dot variative coefficients (Dvc) [ 29 ], Liu with coefficients 24 (L24), and 50 (L50) [ 57 ], and Cheremkhin (Ch) [ 29 ] were added to the comparison.…”

“…However, only the Otsu global thresholding [ 24 ] was applied in the past. There are groups of binarization methods that can potentially provide better results [ 27 , 28 , 29 , 30 , 31 ].…”

Optimization algorithm for amplitude-only hologram based on digital micromirror device

“…However, the current SLMs are capable to display either the amplitude or the phase component of the complex amplitude hologram. Although the diffraction efficiency of phase-only SLMs is high, their refresh rates are low, in contrast, amplitude-only SLMs such as DMDs have received widespread attention due to their high refresh rates that enable color and dynamic displays [5][6][7][8] . The main encoding methods for AOH are detour phase encoding, Lee's four-step encoding [9][10] , and modified off-axis reference beam encoding 11 , with the latter also known as the Burch encoding method (BEM).…”

Performance Estimation of Intensity Accumulation Display by Computer-Generated Holograms

“…Although optimization algorithms, such as binary search [7][8][9] or simulated annealing [10], can be applied to improve the quality of binary CGH display, the quality of a single binary CGH is still limited. Error diffusion [11][12][13] can generate a binary CGH with good quality only when the object distance, the normalization factor, and the weighting factors are optimized. Super-pixel display schemes [14][15][16] can achieve high-quality display by binary CGHs.…”