• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.706-713
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• 2014

An enhanced 360-degree integral-floating three-dimensional display system using a hexagonal lens array and a hidden point removal operator is proposed. Only the visible points of the chosen three-dimensional point cloud model are detected by the hidden point removal operator for each rotating step of the anamorphic optics system, and elemental image arrays are generated for the detected visible points from the corresponding viewpoint. Each elemental image of the elemental image array is generated by a hexagonal grid, due to being captured through a hexagonal lens array. The hidden point removal operator eliminates the overlap problem of points in front and behind, and the hexagonal lens array captures the elemental image arrays with more accurate approximation, so in the end the quality of the displayed image is improved. In an experiment, an anamorphic-optics-system-based 360-degree integral-floating display with improved image quality is demonstrated.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.1-8
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• 2012

According that most integral imaging techniques have used rectangular lens array, this integrated distribution of light is recorded in the form of a rectangular grid. However, hexagonal lens array gives a more accurate approximation of ideal circular lens and provides higher pickup/display density than rectangular lens array[4]. Using the parallel processing technique in order to generate the elemental imaging for hexagonal lens array, each pixel that compose the elemental imaging should be determined to belong to the hexagonal lens. This process is output to the screen for every pixel in progress, and many computations are required. In this paper, we have proposed parallel processing method using an OpenCL to generate the elemental imaging for hexagonal lens array in 3D volume date. In the experimental result of proposed method show speed of 20~60 fps for hexagonal lens array of $20{\times}20$ sizes and input data of Male[$128{\times}256{\times}256$] volume data.

• Tribology and Lubricants
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• v.24 no.6
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• pp.368-373
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• 2008

This paper will investigate the friction characteristics of a 100m Hexagonal Array, Micro-scale Dimple Pattern, on bearing steel. These characteristics are researched by utilizing a pin-on-disk wear test machine, under various test conditions. The reduction of friction is a necessary requirement for the improved efficiency of this machine. As the speed increases, there is a decrease in the effect of the dimple of friction characteristic, with substantially little change to density. Conversely, as the load increases, the dimple pattern grows larger, resulting in a difference in the texture of these two components. At a dimple density of 10% the friction characteristic is easily demonstrated, with a consistent change in both speed and load.

• Journal of IKEEE
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• v.26 no.1
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• pp.129-132
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• 2022

In this paper, a technique for optimizing the sub-array system structure that can minimize the side lobe level of the phased-array antenna is proposed. Optimization of the proposed array antenna structure is to adjust the spacing between sub-arrays and sub-arrays by using a hexagonal array structure of one sub-array and a hexagonal sub-array for six hexagonal arrays, and thus the entire phased array antenna system of the radiation pattern was optimized. Compared to the 2-dimensional planar antenna system, the proposed technique maintains a gain of 24.3 dBi and a half-power beam-width of 8.46 degrees without change, and only reduces -3.4 dB and -6.5 dB in the x-axis and y-axis directions, respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.347-350
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• 2003

Optimization of the luminance, luminous efficiency, and address voltage margin characteristics has been made on the delta color array PDP with various hexagonal shape subpixels. The optimal subpixel and electrode designs are obtained for the 42-inch high-definition PDP ($1,366{\times}768$) with the fine pixel pitch less than 0.7 mm. The hexagonal delta array structure shows more improved characteristics than that of the normal delta array structure with rectangular shape subpixels.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.561-568
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• 2018

Purpose : The size and regular array of the collagen fibers in the corneal stroma have very close correlation with transparency. Simulation was carried out to investigate the change of light transmittance according to the array structure and collagen fiber layer thickness. Methods : The collagen fibers in corneal stroma were arranged in regular hexagonal, hexagonal, square and random shapes with OptiFDTD simulation software, and the light transmittance was analyzed. In square array, the light transmittance according to the density change was confirmed by when the number of collagen fibers in the simulation space was the same and the light transmittance was examined when the number and density of collagen fibers were changed. Results : When the number of collagen fibers is the same, the density becomes smaller and the thickness of the fibrous layer becomes thicker in order of arrangement of square, regular hexagonal, random and hexagonal. As a result of measuring the light transmittance by changing the array structure, the light transmittance measured at the detector at the same position was almost similar regardless of the array structure. In the detectors D0, D1, D2 and D3, the maximum transmittance is shown in square, hexagonal and square, regular hexagonal and regular hexagonal array structure, and the minimum transmittance is hexagonal, random, hexagonal and square, and square array structure. However, the difference between the maximum transmittance and the minimum transmittance was almost the same within 1%. When the number of collagen fibers was the same, the light transmittance of the rectangular array structure decreased with increasing fiber layer thickness. And as the thickness increased, the light transmittance decreased more when the number of collagen fibers decreased. Conclusion : Even though the collagen array structure changed, the light transmittance is almost similar regardless of the arrangement structure. However, as the array structure was changed, the thickness of the collagen fiber layer changed, and as the thickness increased, the light transmittance decreased. In other words, the transparency of the corneal stroma is more closely related to the thickness of the fibrous layer than the array of collagen fibers.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1434-1440
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• 2014

This paper describes a demosaicking method for hexagonally-structured color filter array. Demosaicking is essential to acquire color images using color filter array (CFA) in single sensor imaging. Thus, CFA patterns have been discussed in order to improve image quality in single sensor imaging after the Bayer pattern are introduced. Advancements in imaging sensor technology recently introduce a hexagonal CFA pattern. The hexagonal CFA can be considered to be a 45-degree rotational version of the Bayer pattern, thus demosaicking can be implemented by an existing method with backward and forward 45-degree rotations. However, this approach requires heavy computing power and memory in image sensing devices because of the image rotations. To overcome this problem, we proposes a demosaicking method for a hexagonal Bayer CFA without rotations. In addition, we introduce a weighting parameter in our demosaicking method to improve image quality and to unifying exiting method with our method. Experimental results indicate that the proposed method is superior to conventional methods in terms of PSNR. In addition, some optimized values for the weighting parameter are provided experimentally.

• Journal of Korea Multimedia Society
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• v.20 no.12
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• pp.2009-2015
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• 2017

A two-dimensional lens is required to reproduce both the horizontal and vertical parallax through an autostereoscopic 3D display. Among the two-dimensional lenses, a hexagonal micro lens array (MLA) having good optical efficiency is mainly used. However, the hexagonal MLA has complex geometric features. The first feature is that the lens cells are zigzagged in the vertical direction, which should be reflected in the view number calculation for each sub-pixel. The second feature is that the four sides of a hexagonal lens cell are tilted, requiring a more careful view index assignment to the lens cell. In this paper, we propose a sub-pixel multiplexing scheme suitable for the features of the hexagonal MLA. We also propose a view-overlay algorithm based on a two-dimensional lens and compare subjective image quality with existing view-selection through autostereoscopic 3D display implementation.

• Journal of KSNVE
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• v.10 no.1
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• pp.123-128
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• 2000

This paper describes the optimization of the hexagonal array transducer using finite element method. The transducer consists of the disc type sensors. Three dimensional beam patterns of each element and the array transducer are analysed using the finite element code ATILA. Beam patterns were analyzed for the disc type transducer. To optimize beam patterns of the array transducer, Chebyshev polynomial weight is applied to each element. In case of applying optimized weight, a 30 degree width beam pattern is presented at 10kHz. This paper also includes the effect of rubber filling material instead of using the water inside the transducer array.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.86-91
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• 2016

Convenient design guideline for Waveguide-below-cutoff (WBC) array is proposed to obtain the minimum waveguide length for electromagnetic pulse (EMP) shielding. The analysis includes circular, rectangular, and hexagonal WBC, determine the total length of the waveguide. When the unit side of rectangular WBC and the diagonal line of hexagonal WBC are given as 30 mm, the length of hexagonal WBC is 5 mm shorter than rectangular case with shielding effectiveness (SE) 80 dB. The length difference is deepened with SE of 100 dB, which shows approximately 30 mm shorter length for hexagonal case than others. In addition, hexagonal WBC requires much shorter length than circular WBC. In conclusion, hexagonal case is the most effective with respect to flow velocity and pressure loss for equivalent SE.