• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.167-170
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• 2010

In this paper, we proposed a novel algorithm to detect the center of pupil in frontal view face. This algorithm, at first, extract an eye region from the face image using integral projection function and variance projection function. In an eye region, detect the center of pupil positions using circular hough transform with sobel edge mask. The experimental results show good performance in detecting pupil center from FERET face image.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.101-106
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• 2016

A pupil filter is a useful technique for modifying the light intensity distribution near the focus of an optical system to realize depth of field (DOF) extension and superresolution. In this paper, we proposed a new design of the phase only pupil filter by using Zernike polynomials. The effect of design parameters of the new filters on DOF extension and superresolution are discussed, such as defocus Strehl ratio (S.R.), superresolution factor (G) and relative first side lobe intensity (M). In comparison with the other two types of pupil filters, the proposed filter presents its advantages on controlling both the axial and radial light intensity distribution. Finally, defocused imaging simulations are carried out to further demonstrate the effectiveness and superiority of the proposed pupil filter on DOF extension and superresolution in an optical imaging system.

• Journal of the Optical Society of Korea
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• v.17 no.3
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• pp.249-254
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• 2013

In ophthalmology, a pupillometer, a device to measure the diameter of the pupil of the eye, can provide information on the function of the autonomic nervous system. The current pupillometers on the market are either too large to be a handheld instrument, or relatively expensive. In this study, a pupillometer based on a smartphone was designed. Both white and infrared LEDs and a 3M pixel camera of a smartphone were applied for the visual stimuli to an eye and for the acquisition of the eye images, respectively. Contrary to the existing method of pupil measurement that usually observe the variation of pupil diameter, the proposed algorithm in this study was applied to calculate the constriction ratio of the pupillary area in response to pupillary light reflex. The results showed that the constriction ratio of the pupillary area were all in the normal range (above 4.0) from the sixteen healthy participants. It is believed that the approach to pupil measurement used in this study is suitable for a mobile interface, and this system can be applied to clinical research, home-use healthcare, and distributed to some areas which suffer from problems like a lack of medical support.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.828-831
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• 2005

In this paper we propose a method to detect human faces from color image using pupil-template matching. Face detection is done by three stages. (i)separating skin regions from non-skin regions; (ii)generating a face regions by application of the best-fit ellipse; (iii)detecting face by pupil-template. Detecting skin regions is based on a skin color model. we generate a gray scale image from original image by the skin model. The gray scale image is segmented to separated skin regions from non-skin regions. Face region is generated by application of the best-fit ellipse is computed on the base of moments. Generated face regions are matched by pupil-template. And we detection face.

• Journal of the Korea Society of Computer and Information
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• v.14 no.12
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• pp.89-96
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• 2009

A lot of information is contained in an image or a movie rather than in a text, and it is very important thing to extract context from them. In this study, we propose a method to detect an open/closed eye and determine the location of a pupil in an eye image which is extracted from a movie. The image is normalized using transformation into bipolarization with white and black color and horizontalizing, and we measure width and height of an eye. With these information, we can determine the open or closed eye and the location of the pupil. Experiments were done with 52 images of eyes from movies using this method, and we get good results with 98% of correctness in detection of open/closed eyes and 95% in detection of pupil's location.

• Current Optics and Photonics
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• v.7 no.6
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• pp.745-754
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• 2023

In order to test the recognition ability and accuracy of a target imaging simulator under the irradiation of solar stray light in a laboratory environment, it needs to be fixed on a five-axis turntable during a hardware-in-the-loop simulation test, so the optical system of the simulator should have a long exit pupil distance. This article adopts a secondary imaging method to design a projection optical system suitable for thin-film-transistor liquid crystal displays. The exit pupil distance of the entire optical system is 1,000 mm, and the final optimization results in the 400 nm-850 nm band show that the modulation transfer function (MTF) of the optical system is greater than 0.8 at the cutoff frequency of 72 lp/mm, and the distortion of each field of view of the system is less than 0.04%. Combined with the design results of the optical system, TracePro software was used to model the optical system, and the simulation of the target imaging simulator at the magnitude of -1 to +6 Mv was analyzed and verified. The magnitude error is less than 0.2 Mv, and the irradiance uniformity of the exit pupil surface is greater than 90%, which meets the requirements of the target imaging simulator.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.179-181
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• 2004

본 논문에서는 변형 삼각간섭계를 이용한 간섭패턴 생성과 관련한 몇 가지 실험결과를 제시한다. Two-pupil 합성 방법을 이용하여 변형 삼각간섭계의 광전달함수를 합성하고 광전달함수에 내포된 오차에 대한 원인을 분석해 보았다.

• Korean Journal of Optics and Photonics
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• v.9 no.4
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• pp.227-230
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• 1998

The Strehl ratio(SR) expressions are derived from the diffration intensity distribution in a Gaussian pupil imaging system, and Marechal criterion is applied for the case of astigmatism aberration first and then to all the rest of the Seidel 1st order aberrations. The aberration criteria obtained are tabulated. In the case of Rayleigh's pupil, the same criteria are always smaller than Gaussian pupil, thus the latter is superior to the former.

• Journal of information and communication convergence engineering
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• v.3 no.1
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• pp.56-61
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• 2005

In this paper, we present a video rate control scheme for storage and delivery in which the time-varying viewing interests are controlled by human gaze. To track the gaze, the pupil's movement is detected using the three-step process : detecting face region, eye region, and pupil point. To control bit rates, the quantization parameter (QP) is changed by considering the static parameters, the video object priority derived from the pupil tracking, the target PSNR, and the weighted distortion value of the coder. As results, we achieved human interfaced visual model and corresponding region-of-interest rate control system.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.25 no.4
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• pp.327-336
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• 2021

In this paper, we will introduce the image processing methods for the remote pupillary light reflex measurement using the video taken by a general smartphone camera without a special device such as an infrared camera. We propose an algorithm for estimate the size of the pupil that changes with light using image data analysis without a learning process. In addition, we will introduce the results of visualizing the change in the pupil size by removing noise from the recorded data of the pupil size measured for each frame of the video. We expect that this study will contribute to the construction of an objective indicator for remote pupillary light reflex measurement in the situation where non-face-to-face communication has become common due to COVID-19 and the demand for remote diagnosis is increasing.