• Journal of Korea Spatial Information System Society
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• v.11 no.1
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• pp.137-144
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• 2009

Understanding lane markings in a live video captured from a moving vehicle is essential to build services for intelligent vehicles such as LDWS(Lane Departure Warning Systems), unmanned vehicles, video-based car navigation systems. In this paper, we present a novel approach to recognize the color of lane markings and the lane number that he/she is driving on. More specifically, we present a background-color removal approach to understand the color of lane markings for various illumination conditions, such as backlight, sunset, and so on. In addition, we present a probabilistic network approach to decide the lane number. According to our experimental results, the proposed idea shows promising results to detect lane number in a various illumination conditions and road environments.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.1029-1035
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• 2013

This paper proposes a real time lane detection algorithm using LRF (Laser Range Finder) for autonomous navigation of a mobile robot. There are many technologies for safety of the vehicles such as airbags, ABS, EPS etc. The real time lane detection is a fundamental requirement for an automobile system that utilizes outside information of automobiles. Representative methods of lane recognition are vision-based and LRF-based systems. By the vision-based system, recognition of environment for three dimensional space becomes excellent only in good conditions for capturing images. However there are so many unexpected barriers such as bad illumination, occlusions, and vibrations that the vision cannot be used for satisfying the fundamental requirement. In this paper, we introduce a three dimensional lane detection algorithm using LRF, which is very robust against the illumination. For the three dimensional lane detections, the laser reflection difference between the asphalt and lane according to the color and distance has been utilized with the extraction of feature points. Also a stable tracking algorithm is introduced empirically in this research. The performance of the proposed algorithm of lane detection and tracking has been verified through the real experiments.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.13-23
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• 2010

This study was performed to compare the quality of image processing between the newly developed prototype using light emitting diode(LED) and the conventional $DIFOTI^{TM}$ system(EOS Inc., USA). To estimate the optimal light emitting power for the improved images, primary enamel surfaces treated under Carbopol 907 de-mineralizing solution were taken daily during 20 days of experimental periods by both DIFOTI systems. The results of comparative analyses on the images obtained from both systems with polarized image as gold standard can be summarized as follows: 1. Trans-illumination indices of images taken from primary enamel surfaces were decreased with time in both systems. 2. The differences of intensity of luminance between sound and de-mineralized enamel surface in prototype DIFOTI system was shown to be relatively smaller than conventional $DIFOTI^{TM}$ system. 3. From the comparative analysis of images from both DIFOTI system with polarized images as gold standard, the difference between sound and de-mineralized enamel surface of intensity of luminance of $DIFOTI^{TM}$ system was more correlated to polarized images than prototype of DIFOTI system. With the optimal LED emitting power, the control of aperture of digital camera is considered as the another key factor to improve the DIFOTI images. For the best image quality and analysis, the development of the improved image processing software is required.

• KIEAE Journal
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• v.8 no.1
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• pp.45-52
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• 2008

Daylighting systems can improve the luminous quality of indoor environment and reduce the building's electric lighting energy consumption. For designing good daylighting, place the light where it is desired and avoid excessive contrasts, glare and high light levels. Sun scoop, light scoop and sun catcher systems have been used for alternative systems compared to other natural lighting systems. This study aims to evaluate daylighting performance of sun scoop, light scoop and sun catcher systems using scale model experiments. For the purpose, the 1/10 scale models of the systems were made as the same areas of glazing(10 percent of floor area) on the top of the center roof. Totally 15 measuring points of illuminance on the horizontal work plane were monitored from 09:30 to 12:30 on October 29, 2007. Agilent data logger and photometric sensors Li-cor were used. As the results, the topside lighting systems can improve the illumination uniformity than side lighting and top lighting. However, the appropriated shading system should be integrated to prevent the direct sunlight.

• Korean Journal of Agricultural Science
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• v.39 no.3
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• pp.407-412
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• 2012

Soil texture has an important influence on agriculture such as crop selection, movement of nutrient and water, soil electrical conductivity, and crop growth. Conventionally, soil texture has been determined in the laboratory using pipette and hydrometer methods requiring significant amount of time, labor, and cost. Recently, in-situ soil texture classification systems using optical diffuse reflectometry or mechanical resistance have been reported, especially for precision agriculture that needs more data than conventional agriculture. This paper is a part of overall research to develop an in-situ soil texture classification system using image processing. Issues investigated in this study were effects of sensor travel speed and light source and intensity on image quality. When travel speed of image sensor increased from 0 to 10 mm/s, travel distance and number of pixel were increased to 3.30 mm and 9.4, respectively. This travel distances were not negligible even at a speed of 2 mm/s (i.e., 0.66 mm and 1.4), and image degradation was significant. Tests for effects of illumination intensity showed that 7 to 11 Lux seemed a good condition minimizing shade and reflection. When soil water content increased, illumination intensity should be greater to compensate decrease in brightness. Results of the paper would be useful for construction, test, and application of the sensor.

• Korean Journal of Optics and Photonics
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• v.26 no.4
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• pp.226-232
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• 2015

A double-layer LED array together with an illumination optical system is proposed as a possible light source for LC projection display systems for large screens, up to $8m{\times}6m$ (400 inches diagonal). The heat dissipation problem of the LED array is solved by arranging the LEDs in double layers, and thermal analysis shows its effectiveness. The light from the LEDs in the back layer can be transmitted through the front layer without significant loss by arranging the LEDs in non-overlapping positions in the two layers and inserting suitable microlenses between the two layers and holes in the first layer. Together with the double-layer LEDs, an illumination optical system is designed to illuminate liquid crystal panels with good uniformity and appropriate matching with the projection optics.

• Journal of Korea Multimedia Society
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• v.16 no.9
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• pp.1031-1043
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• 2013

Extracting hand region from images is the first part in the process to recognize hand posture and gesture interaction. Therefore, a good segmenting method is important because it determines the overall performance of hand recognition systems. Conventional hand segmentation researches were prone to changing illumination conditions or limited to the ability to detect multiple people. In this paper, we propose a robust technique based on the fusion of skin-color data and depth information for hand segmentation process. The proposed algorithm uses skin-color data to localize accurate seed location for region-growing from a complicated background. Based on the seed location, our algorithm adjusts each detected blob to fill up the hole region. A region-growing algorithm is applied to the adjusted blob boundary at the detected depth image to obtain a robust hand region against illumination effects. Also, the resulting hand region is used to train our skin-model adaptively which further reduces the effects of changing illumination. We conducted experiments to compare our results with conventional techniques which validates the robustness of the proposed algorithm and in addition we show our method works well even in a counter light condition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.517-525
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• 2006

In this paper, the algorithm which improve the efficiency of surveillance in spite of the change of light is proposed and confirmed by virtue of the experiments. One of the problems for the implementation of visual surveillance system is the image processing technique to overcome with the variations of illumination lights. Some conventional systems are generally not considered the error due to the change of lights because the system use at indoor. In practical, the factors of bad image can be classified to the ghosts due to the reflection of lights and shadows in a scene. Especially weak images and noises at night are decreased the performance of visual surveillance system. In the paper, the filter which improve the images with some change of illumination lights is designed and the gabor filter is used for recognition and tracking of the moving objects. In the results, the system showed that the recognition and tracking were obtained $92\sim100%$ of recognition rate at daytime, but $80\sim90%$ of nighttime.

• Journal of the Korean Solar Energy Society
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• v.22 no.3
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• pp.47-56
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• 2002

The office is an excellent candidate for implementing daylighting techniques because of the relatively high electric lighting power densities and long daytime use pattern. The quantity of light available for a space can be translated in term of the amount of energy savings through a process of a building energy simulation. To get significant energy savings in general illumination, the electric lighting system must be incorporated with a daylight - activated dimmer control. A prototype configuration of an office interior has been established and the integration between the building envelope and lighting and HVAC systems is evaluated based on computer modeling of a lighting control facility. First of all, an energy-efficient luminaire system is designed for both a totally open-plan office interior and a partitioned office. A lighting design and analysis program, Lumen-Micro 2000 predicts the optimal layout of a conventional fluorescent lighting fixture to meet the designed lighting level and calculates unit power density, which translates the demanded amount of electric lighting energy. A dimming control system integrated with the contribution of daylighting has been applied to the operating of the artificial lighting. Annual cooling load due to lighting and the projecting saving amount of cooling load due to daylighting under overcast diffuse sky are evaluated by a computer software, ENER-Win. In brief, the results from building energy simulation with measured daylight illumination levels and the performance of lighting control system indicate that daylighting can save over 70 percent of the required energy for general illumination in the perimeter zones through the year. A 25 % of electric energy for cooling may be saved by dimming and turning off the luminaires in the perimeter zones.

• Journal of the Korean Solar Energy Society
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• v.35 no.3
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• pp.27-39
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• 2015

Under the goal of analyzing the compulsory supply share of new renewable energy according to the application of a daylighting system to indoor gymnasiums, this study conducted analysis of energy consumption and operation schedule at three indoor gymnasiums in the nation through a survey. The investigator did an Energy Plus simulation on Building A based on the analysis results and analyzed the supply share of new renewable energy in the saving effects of lighting energy according to the application of a daylighting system. As a result, When 92 prism daylighting system were installed in the upper ceiling of a stadium, they were able to meet the criteria for the minimum illumination for official games(Min : 600㏓) and optimum illumination for general games and recreations, thus saving lighting energy during the daytime(09:00~17:00). The resulting saving effects of lighting energy amounted to 44.4% for official games, 57.6% for general games, and 66.7% for recreations. In addition, the daylighting systems had a compulsory supply share of new renewable energy at 2.04% for official games, 2.75% for general games, and 2.62% for recreations, recording an average compulsory supply share of 2.5%.