• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.3
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• pp.10-18
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• 2003

In this paper, we propose an optical encryption system based on the encryption of information using the phase component of a wavefront and orthogonal polarization in a Mach-Zehnder interferometer. Since the incoherence of the two perpendicularly polarized lights removes interference component, the decrypted image is stable. In encryption process, the original image is converted into an image having random polarization state by the relative phase difference of horizontal polarization and vertical polarization, so we cannot obtain the original information from the random polarization distribution. To decrypt an Image, the random polarization distribution of encrypted image is divided into two orthogonal components, then key image must be placed on vertical path of Mach-Zehnder interferometer. The decrypted image is obtained In the form of intensity by use of an analyzer.

• Journal of Multimedia Information System
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• v.7 no.4
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• pp.239-248
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• 2020

The performance of the facial recognition system is determined by many technical factors. Further, most of the technical factors have been realized or are still in continued research. The recognition rate has a great influence on performance not only by technical factors but also by other factors. However, researchers are trying to improve the recognition rate by focusing only on technical factors. The mechanism of recognizing is to compare a face image obtained by photography to an already stored face image and determine the score of the similarity. However, if the photographed image is damaged by external light, even a system with a good algorithm will fail to recognize it. Therefore, it is important to prevent the disturbance of light entering from the outside, so it should be blocked, but the camera will not work without light. Thus, it is proposed that a method to secure the external light but block the disturbance of light that affects photography. A method of blocking disturbance light is to use a polarization filter. There are three polarization methods: circular polarization, linear polarization, and elliptical polarization. In this paper, an experiment was performed to overcome disturbance of light using only a circularly polarized filter. In addition, a lighting system that reproduces disturbance light was provided for the experiment, and light of varying intensities and angles was installed to affect the face recognition camera. As a result of actual application, it was determined that a very improved recognition performance in various disturbance light environments.

• Journal of the Optical Society of Korea
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• v.7 no.4
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• pp.234-239
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• 2003

Objective methods to assess quantitatively port wine stain (PWS) blanching in response to laser therapy are needed to improve laser therapeutic outcome. Previous studies have attempted to assess objectively PWS color based on point measurement devices. To date, these approaches have typically been limited by a number of factors such as small test area and need for contact. To address these issues, a polarization spectral imaging system and an image analysis method have been developed to evaluate quantitatively erythema and melanin content distribution in skin. The developed polarization spectral imaging system minimizes artifacts such as glaring, shadowing, and non-uniform illumination that interfere with image fidelity. Furthermore, the image analysis method has been employed to get images of skin melanin and erythema indices from the acquired color images for quantitative analysis. Finally, using PWS patient color image, the effectiveness in laser treatment of PWS was evaluated by calculating relative erythema index image that is the relative erythema index of PWS region to the normal region. The developed device and analysis method appears to be a simple and effective method for quantitative analysis of PWS blanching.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.195-198
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• 2007

In this paper, we introduce a digital cross-polarization and fluorescent color imaging system for quantitative evaluation of skin lesions. We describe the characterization of the imaging systems and the quantitative image analysis methods to show the feasibility for quantitative evaluation of skin lesions. The polarization color image was used to compute erythema and melanin index image which are useful for quantitative evaluation of pigmentation and vascular skin lesions, respectively. The fluorescent color image was used to quantitatively evaluate "sebum" and "vitiligo". In quantitative evaluation of various skin lesions, we confirmed the clinical efficacy of the imaging systems for dermatological applications. Finally, we sure that the imaging systems can be utilized as important assistant tools for the evaluation of skin lesions by providing reproducible quantitative result for widely distributed skin lesions.

• Journal of the Optical Society of Korea
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• v.16 no.3
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• pp.256-262
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• 2012

We derive the point-spread function of the reconstructed image from a point-source complex hologram, which includes phase error caused by polarization components, in the longitudinal direction of the point-spread function and analyze the effect of the error sources of polarization components having influence on image reconstruction of a point-source complex hologram in incoherent triangular holography.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.286-287
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• 2003

Polarization-sensitive optical coherence tomography (PS-OCT) was developed to image highly scattering tissues with accounting for polarization effects in the sample. These polarization-sensitive images can provide additional information on the structure of the tissue because of a polarization state of the light is changed at its interaction with biological tissues. The scattering and birefringence are two phenomena, which change the polarization state of light passing through medium. (omitted)

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.18-23
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• 2019

The image projected onto the screen of the floating hologram is no more than a two-dimensional image. Although it creates an illusion that an object appears to float in space as it moves around while showing its different parts. This paper has proposed a novel method of floating 3D hologram display to view stereoscopic three-dimensional images without putting on glasses. The system is comprised of a sharkstooth scrim screen, projector, polarizing filter for the projector, and a polarizing film to block the image projected from the sham screen. As part of the polarization characteristics, the background image and the front object have completely been separated from each other with the stereoscopic 3D effect successfully implemented by the binocular disparity caused by the distance between the two screens.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.60-61
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• 2003

We proposed an optical encryption system using circular polarization based on interferometer. The phase modulated input image, represented as orthogonal linearly polarized states respectively, is encrypted into circularly polarized states using polarization modulated masks. In the decryption we use the inverse matrix of polarization modulation mask and can recover the original polarization states.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.205-210
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• 2005

A new configuration of LCD projectors for polarized stereoscopic projection having no light loss in the polarization process is suggested. In the proposed system, two polarizing filters that are employed in the conventional LCD polarized stereoscopic projection system causing additional light loss and image distortion are excluded by taking into account of polarization property of the LCD projector and image processing techniques. From some experimental results by using the Type-1 LCD projectors of NEC MT 1060R, light loss of the proposed system occurring in the polarization process is found to be zero and the resultant stereoscopic video image projected from this system is also found to be 213%, 75% and 300% brighter than those projected from the conventional Type-1 LCD projector-based, Type-2 LCD projector-based and Type-3 projector-based systems, respectively.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.534-537
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• 2005

Polarization of the radar wave refers to the ellipticity angle and orientation angle of the polarization ellipse. An evaluation of the polarization response can help understand the scattering mechanisms involved for a particular area of interest or provide information for image classification and algorithm section. C- and L-band polarization responses measured at urban area show the results that the polarization behavior for dihedral comer reflector or short, thin cylinder reflector appears at located in city streets or buildings site which are lined up and the polarization behavior for a large conducting sphere appears at parts of test site particularly river, flat, and vegetated areas. Also, the co- and cross-polarized response graphs and polarimetric parameters are discussed.