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Abstract We analyzed the effect of modified mono-vision prescription on the occupational progressive addition lenses (OPALs) in presbyopia for indoor use as a method to solve the inconvenience caused by the decrease in the intermediate and the near distances' vision when the PALs worn. To analyze the effect, 37 subjects (57.22 ± 5.18 years) were selected who were wearing PALs and had working hours over 6 h per day on average at intermediate and near distances. Entire tests were carried out with regard to three cases: subjects wearing PALs, occupational progressive addition lenses (OPALs), and prescription for modified mono-vision of OPALs. In order to compare visual performance of three cases, our study evaluated corrected visual acuity and subjective satisfaction at far, intermediate and near distances, stereo-acuity and phoria at far and near distances. The results showed that the prescription of modified mono-vision of OPALs could be useful when applied to the clinical practices for prescribing presbyopic correction. [ABSTRACT FROM AUTHOR]

In this paper, we propose image visualization method of photon counting confocal microscopy using statistical estimation. Since high power coherent light source is used to record sectional images from micro-objects in conventional confocal microscopy, it may cause damage for a structure of micro-objects. Thus, low power coherent light source may be required. However, in low light level environment, it is difficult to capture sectional images of micro-objects. On the other hand, photon counting imaging technique can detect sectional images of micro-objects in photon-starved conditions. Therefore, in this paper, we apply a photon counting imaging technique to conventional confocal microscopy for visualization of micro-objects. Photon counting detection can be modeled by statistical process. To visualize micro-objects under photon-starved conditions, statistical estimation methods such as maximum likelihood estimation can be used. In addition, we present color photon counting imaging system which considers different carried photon energy with each basic color channels. To prove and evaluate our method, we show simulation results for image visualization of photon counting confocal microscopy and calculate mean square error. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new approach for viewing angle enhancement in a parallax barrier based one-dimensional (1D) integral imaging display system. The viewing angle in a parallax barrier integral imaging system is defined by the angle between the center of slit and exit ray from elemental image. In this regard, we employ a refractive index medium between the elemental image plane and parallax barrier. Thus, the use of a refractive index medium allows us to increase the angle of exit ray, and may result in a viewing angle enhancement of display system. To test the feasibility of the proposed method, experiments are carried out and the results are comparatively analyzed with the conventional method. Experimental results reveal that the proposed method outperforms the conventional method. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new 3-D computational reconstruction method in diffraction grating imaging. Diffraction grating imaging has advantages in terms of system complexity in generating a parallax image array (PIA) for 3-D imaging. In general, a computational reconstruction of 3-D images isś implemented with a back-projection algorithm of PIA. Therefore, the PIA obtained by a camera array and a lens array based system requires the process of defining and extracting the individual parallax image region in advance. However, since the PIA in a diffraction grating imaging is generated by a single optical element, so there is no suitable method to detect the region of individual parallax images from captured PIA. In addition, it is almost impossible to extract individual parallax image regions when parallax images of different orders overlap each other in the PIA. As a 3-D computational reconstruction method that solves this problem in diffraction grating imaging, we propose a method of extracting a spatially filtered PIA from an original PIA. The proposed method theoretically derives the periodicity and intensity of a PIA by optically analyzing the acquisition process of a PIA. Reconstruction of 3-D object image is realized through the superposition by convolution of parallax images with the same period. The proposed 3-D computational reconstruction may be an optimized method for diffraction grating imaging because it does not require the extraction of individual parallax image regions. The proposed theoretical analysis and computational reconstruction verified the usefulness in 3-D imaging through the optical experimental results. [ABSTRACT FROM AUTHOR]

The relation between the imaging characteristics of parallax images (PIs) and the system parameters of the double diffraction grating (DDG) imaging system is analyzed. DDG imaging method may produce parallax images (PIs) efficiently. However, a geometrical analysis is required to improve the applicability of the imaging system. The system parameters considered include the wavelength of light source, the spatial resolution of the diffraction grating, and positions of diffraction gratings and an imaging lens. The imaging characteristics of the DDG imaging defined and described in terms of positions and parallax angles of PIs. The ray-optical analysis is performed for the explanation of the imaging characteristics. [ABSTRACT FROM AUTHOR]

We propose a depth resolution improved target depth image extraction method in integral imaging by using the convolution property between periodic functions (CPPF) with image interpolation algorithm. We derive the depth resolution equation of a direct pickup system and analyze the factors related to the change of the depth resolution which are the focal length of an elemental lens and the resolution of an elemental image. We investigate the effect according to the change of these factors. The simulation results show that the key factor to change the depth resolution is the resolution of an elemental image. To show the feasibility of the proposed method, we carry out the preliminary experiments and present the results. [ABSTRACT FROM AUTHOR]

We analyzed the optical and structural characteristics of the three types of glasses supplied to South Korean soldiers with ametropia, which are conventional glasses (CG), ballistic safety insert glasses (BSIG) and gas-mask insert glasses (GMIG), to developed compatible multiple purpose glasses (CMPG). The size of each glasses was structurally analyzed including a lens insert parts, a bridge part, and a front part. In order to confirm the optical condition of each glasses, it was analyzed including vertex distance, face form angle, and pantoscopic angle while wearing each glasses. Based on these analyses, we designed and developed CMPG. Three-dimensional (3-D) scanning and printing techniques were used for CMPG production. In order to verify the feasibility and usefulness of CMPG, we performed comparative experiments with the three types of glasses currently supplied by the military. 37 active soldiers with ametropia participated in the experiment and their high and low contrast corrected visual acuity for far distance, binocular visual fields, and subjective satisfaction was measured after wearing the three types of glasses and CMPG. The CMPG developed in this research will improve the visual satisfaction of soldiers with ametropia and contribute to the improvement on operational capability. [ABSTRACT FROM AUTHOR]