• The Transactions of the Korea Information Processing Society
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• v.7 no.3
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• pp.1000-1012
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• 2000

There are many factors for face recognition. Two of those are orientation and brightness of illumination. In early studies of face recognition, with fixing these factors to good conditions th goal of research was focused on improving recognition rate itself. But they are very important factors to be solved for implementing face recognition system. In this paper, two methods wer proposed to minimize the influence of illumination. One is the local difference filter to reduce the influence fo variation of illumination. The other is weight function considering the horizontal difference of intensity. Applying tow proposed methods, the resultant recognition rate revealed 86.5% for 275 test images.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.265-272
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• 2009

In this paper, a simple optical method that uses an infrared(IR) cut filter is proposed to minimize variation of eye image by external infrared(IR) sources in a video based head mounted eye tracking system that is used in the field of sports. For this, the IR cut filter is attached to a head mount of the eye tracking system, and the camera with an IR LED is located between the IR cut filter and eye. In this structure, external IR is blocked by the IR cut filter, and the IR intensity on the eye can be controlled by the IR LED. Therefore, the illumination condition of the camera to capture the eye can be stable without being affected by external IR illuminations. To verify the proposed idea, variation of the eye image and intensity of the IR with/without the IR cut filter is measured under various illumination conditions. The measured data show that the IR cut filter method can block external IR effectively, and complex pupil detection algorithms can be replaced by a simple binarized method.

• Journal of Information Processing Systems
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• v.9 no.1
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• pp.141-156
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• 2013

In this paper we propose a method to detect human faces in color images. Many existing systems use a window-based classifier that scans the entire image for the presence of the human face and such systems suffers from scale variation, pose variation, illumination changes, etc. Here, we propose a lighting insensitive face detection method based upon the edge and skin tone information of the input color image. First, image enhancement is performed, especially if the image is acquired from an unconstrained illumination condition. Next, skin segmentation in YCbCr and RGB space is conducted. The result of skin segmentation is refined using the skin tone percentage index method. The edges of the input image are combined with the skin tone image to separate all non-face regions from candidate faces. Candidate verification using primitive shape features of the face is applied to decide which of the candidate regions corresponds to a face. The advantage of the proposed method is that it can detect faces that are of different sizes, in different poses, and that are making different expressions under unconstrained illumination conditions.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.2
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• pp.31-40
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• 2012

Face recognition refers to the process of identifying individuals based on their facial features. It has recently become one of the most popular research areas in the fields of computer vision, machine learning, and pattern recognition because it spans numerous consumer applications, such as access control, surveillance, security, credit-card verification, and criminal identification. However, illumination variation on face generally cause performance degradation of face recognition systems under practical environments. Thus, this paper proposes an novel face recognition system using a fusion approach based on local binary pattern and two-dimensional principal component analysis. To minimize illumination effects, the face image undergoes the local binary pattern operation, and the resultant image are divided into two sub-images. Then, two-dimensional principal component analysis algorithm is separately applied to each sub-images. The individual scores obtained from two sub-images are integrated using a weighted-summation rule, and the fused-score is utilized to classify the unknown user. The performance evaluation of the proposed system was performed using the Yale B database and CMU-PIE database, and the proposed method shows the better recognition results in comparison with existing face recognition techniques.

• Journal of the Korean Solar Energy Society
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• v.32 no.1
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• pp.48-55
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• 2012

In recent years, it clearly shows the tendency toward the utilization of daylight in many exhibitory buildings such as museum since the expectation of visitors for whom high illuminance levels are preferable to perceive the details of the works of art. Shading devices and special glazings are often used as the tool to control the amount of light and heat which should be avoided for the presentation of high-light sensitive art works such as paintings. Another way of controling the light is to provide the space for inducing and attenuating light in the exhibitory building. This study aims to investigate the illuminance on the exhibitory space when the space for inducing and attenuating light is applied. Interaction between the daylight and the space was simulated by Lumen Micro program with variation of the size of the exhibitory space, the length of inner wall, surface reflectivity, area of windows to obtain the illumination of the wall surface. This study shows that those variables affect the illumination on the wall surfaces. By comparing the results with suggestive illumination of KS and ICOM, available wall for display on natural lighting are suggested for the seasons and time.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1470-1472
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• 2003

Hyperion, as hyperspectral data, is carried on NASA’s EO-1 satellite, can be used in more subtle discrimination on forest cover, with 224 band in 360 ?2580 nm (10nm interval). In this study, Hyperion image is used to investigate the effects of topography on the classification of forest cover, and to assess whether the topographic correction improves the discrimination of species units for practical forest mapping. A publicly available Digital Elevation Model (DEM), at a scale of 1:25,000, is used to model the radiance variation on forest, considering MSR(Mean Spectral Ratio) on antithesis aspects. Hyperion, as hyperspectral data, is corrected on a pixel-by-pixel basis to normalize the scene to a uniform solar illumination and viewing geometry. As a result, the approach on topographic effect normalization in hyperspectral data can effectively reduce the variation in detected radiance due to changes in forest illumination, progress the classification of forest cover.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6C
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• pp.815-823
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• 2004

A hue-based attention operator and a combinational integral projection function(CIPF) are proposed to extract the normalized regions of face and facial features robustly against illumination variation. The face candidate regions are efficiently detected by using skin color filter, and the eyes are located accurately nil robustly against illumination variation by applying the proposed hue- and symmetry-based attention operator to the face candidate regions. And the faces are confirmed by verifying the eyes with the color-based eye variance filter. The proposed CIPF, which combines the weighted hue and intensity, is applied to detect the accurate vertical locations of the eyebrows and the mouth under illumination variations and the existence of mustache. The global face and its local feature regions are exactly located and normalized based on these accurate geometrical information. Experimental results on the AR face database［8］ show that the proposed eye detection method yields better detection rate by about 39.3% than the conventional gray GST-based method. As a result, the normalized facial features can be extracted robustly and consistently based on the exact eye location under illumination variations.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.12
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• pp.16-27
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• 2013

This study describes the difference of lighting directing techniques of between asian and westerner in the residential space, and presents the LED lighting environment according to the residents' behaviors. This study was conducted with Koreans, European and North Americans, and the space range was limited to the living room where the various activities occur. The data of the desired LED lighting environment is drawn through lighting technique, illumination color temperature and illuminance variation of LED in living room, and the detailed study results are as follows ; First, the lighting in living space should be made with considering the various behaviors because the expected level according to consideration or not of behavior makes much difference. Second, the comfortably feeling LED lighting environments that are lighting technique, illumination color temperature and illuminance variation, are different between Koreans and North Americans, but Koreans and European feel comfortable under the similar LED lighting environments. Third, the data for the comfortable LED lighting environments is established according to the various residents' behaviors, which are watching TV, reading, studying, relaxing, chatting, entertaining guests. And then, the established LED lighting environments are analyzed with characteristic of behavior and classified according to lighting technique, illumination color temperature and illuminance variation for understanding their characteristic Few studies have been conducted to find out difference of the comfortably feeling LED lighting environment between asians and westerners. Therefore, in this study, it has a great significance to present the difference of the LED lighting environments that asians and westerners feel comfortable in living space, and to draw the characteristic of the expected lighting environment according to residents' behaviors.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2645-2648
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• 2003

In this paper, real-time and reconfiguable hardware filter for face recognition is proposed and implemented on FPGA chip using verilog-HDL. In general, face recognition is considerably difficult because it is influenced by noises or the variation of illumination. Some of the commonly used filters such s histogram equalization filter, contrast stretching filter for image enhancement and illumination compensation filter are proposed for realizing more effective illumination compensation. The filter proposed in this paper was designed and verified by debugging and simulating on hardware. Experimental results show that the proposed filter system can generate selective set of real-time reconfiguable hardware filters suitable for face recognition in various situation.

• Journal of the Optical Society of Korea
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• v.11 no.4
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• pp.183-191
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• 2007

The highest diffraction efficiency(DE) value after illumination and post-curing of photopolymer films were obtained at the $SeO_2$/Acrylamide(AA) Ratios of AA 3.0 g, $SeO_2$ 1.0g and the DE's were stable values of over 90%. By the addition of $SeO_2$, the maximum DE at the initial stage of illumination was reached at 300 seconds, which suggests $SeO_2$ slows down the photopolymerization of AA, which enhances the maximum DE value by giving more migration time. DE variation curve for the optimum composition during extended-time illumination of 9,000 seconds resembles a sine curve due to the combination of the monomer diffusion and the photopolymerization, and the photopolymer film expanded by about 8% after photopolymerization due to monomer migration.