• Development and Reproduction
• /
• v.16 no.2
• /
• pp.101-106
• /
• 2012

Importance of behavior factors or environmental factors in visual organization and visual function of fish is treated with great care in visual ecology, and there is no study about initial ocular growth and development on the dark banded rockfish, Sebastes inermis. Thus, this study was performed. The total length, head length, head depth, eye diameter and lens diameter of the dark banded rockfish showed positive allometric relationship between parturition stage and 60 days post-parturition (dpp). The increase in total length relative to head length and head depth, head length growth relative to eye diameter and lens diameter, and head depth growth relative to eye and lens diameter were nearly isometric. The eyes were formed completely at parturtion stage. At this age, the eye has an optic nerve fiber layer, a ganglion cell layer, an inner plexiform layer, an inner nuclear layer, an outer plexiform layer, an outer nuclear layer, an outer limiting membrane, a rod and cone layer and an epithelial layer. Thickness of retina at 60 dpp was higher than that of at parturition stage. During this experiment, the proportion of the rod and cone layer, outer nuclear layer, and optic nerve fiber layer of retina were significantly increased, while the proportion of the outer plexiform layer, inner nuclear layer and ganglion cell layer of retina were significantly decreased (P<0.05). The essential demands that must be met by the retina in this species pertain to light sensitivity and spatial resolution.

• The Journal of the Korea Contents Association
• /
• v.13 no.8
• /
• pp.11-19
• /
• 2013

This paper presents a simple method to estimate center of distortion and correct radial distortion from fish-eye lens. If the center of image is not locate that of lens in a straight line, the disadvantage of FOV model is low accurate because of correcting distortion without estimated centre of distortion. We propose a method accurately estimating Distortion center using FOV model and 2D pattern from wide angle lens. Our method determines the center of distortion in least error between straight lines and curves with FOV model. The results of experimental measurements on synthetic and real data are presented.

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.7
• /
• pp.634-640
• /
• 2015

This paper proposes a novel three-dimensional mapping algorithm in Omni-Directional Vision SLAM based on a fisheye image and laser scanner data. The performance of SLAM has been improved by various estimation methods, sensors with multiple functions, or sensor fusion. Conventional 3D SLAM approaches which mainly employed RGB-D cameras to obtain depth information are not suitable for mobile robot applications because RGB-D camera system with multiple cameras have a greater size and slow processing time for the calculation of the depth information for omni-directional images. In this paper, we used a fisheye camera installed facing downwards and a two-dimensional laser scanner separate from the camera at a constant distance. We calculated fusion points from the plane coordinates of obstacles obtained by the information of the two-dimensional laser scanner and the outline of obstacles obtained by the omni-directional image sensor that can acquire surround view at the same time. The effectiveness of the proposed method is confirmed through comparison between maps obtained using the proposed algorithm and real maps.

• Journal of the Optical Society of Korea
• /
• v.17 no.4
• /
• pp.336-343
• /
• 2013

Recently various types of driver assistance systems have been used for automobiles. In 2008, the U.S Congress passed a law which required that most cars be equipped with devices to warn objects behind the vehicle. Because of that, market of rear view cameras is expected to rise dramatically. Therefore many suppliers try to provide a wide angle camera for car makers. But a high distortion is caused by the wide angle might result in lower image quality. In order to improve the image quality, normally we use an algorithm to correct a distortion. Though we can improve the distorted image by correction algorithm, we must pay more cost to use it. In this paper, we propose a new optical system reducing a distortion in contrast to a conventional lens without cost. In other words, we can see only an area of interest. That is similar to reducing a field of view. Using a new optical system, we can get a less distorted image. In order to view an area of interest, we introduce an off axis optical system having refractive surfaces and reflective surfaces. In this paper, we describe the results of design and, evaluation of an off axis wide angle compact imaging system. In comparison to conventional wide angle lens, we can get the improvement of MTF, distortion, and lateral color aberrations. And we also can reduce a total cost because we don't need the outer apparatus or bracket to mount on the car.

• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.3
• /
• pp.210-216
• /
• 2016

This paper presents a novel collision avoidance technique for mobile robots based on omni-directional vision simultaneous localization and mapping (SLAM). This method estimates the avoidance path and speed of a robot from the location of an obstacle, which can be detected using the Lucas-Kanade Optical Flow in images obtained through fish-eye cameras mounted on the robots. The conventional methods suggest avoidance paths by constructing an arbitrary force field around the obstacle found in the complete map obtained through the SLAM. Robots can also avoid obstacles by using the speed command based on the robot modeling and curved movement path of the robot. The recent research has been improved by optimizing the algorithm for the actual robot. However, research related to a robot using omni-directional vision SLAM to acquire around information at once has been comparatively less studied. The robot with the proposed algorithm avoids obstacles according to the estimated avoidance path based on the map obtained through an omni-directional vision SLAM using a fisheye image, and returns to the original path. In particular, it avoids the obstacles with various speed and direction using acceleration components based on motion information obtained by analyzing around the obstacles. The experimental results confirm the reliability of an avoidance algorithm through comparison between position obtained by the proposed algorithm and the real position collected while avoiding the obstacles.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.10b
• /
• pp.718-720
• /
• 2004

일반적으로 카메라는 좁은 시각 영역(field of view)를 가짐으로 인해, 넓은 영역의 뷰를 얻기 위해서는 모터를 이용하여 카메라를 팬/틸트시키는 것이 일반적이다. 하지만, 이들은 아직까지 기계적으로 카메라를 직접 움직여 원하는 영역의 영상을 보여주기 때문에, 내구성이 떨어지며 생산 원가도 많이 든다. 또한 움직임으로 인한 모션 블러 현상도 나타난다. 본 논문에서는 한번에 보은 지역을 촬영할 수 있고, 비기계적으로 팬/틸트가 가능한 카메라 시스템을 개발하고자 한다. 한번의 촬영으로 널은 영역을 얻기 위해, 어안렌즈를 CCD 센서와 항께 사용한다. 또한, 어안렌즈(fish-eye lens)를 통해 얻은 왜곡된 영상을 와핑 기술을 이용해 편 다음, 원하는 부분의 영상을 보여준다. 본 논문은 TI사의 TMS320DSC25 프로세서로 구현하였으며, 어안 렌즈 캘리브레이션 및 실시간 왜곡 보정, 영상 출력을 위한 방법을 소개한다.

• 한국공간정보시스템학회:학술대회논문집
• /
• 2007.06a
• /
• pp.133-138
• /
• 2007

본 논문에서는 어안렌즈 및 왜곡경향을 조사하고, 기존 보정기법을 토대로 어안렌즈에 적합한 사진측량학적 기법을 이용한 보정기법을 채용하였다. 이를 이용하여 어안렌즈를 보정하여 왜곡계수를 산출하여, 관측한 영상점을 왜곡이 보정된 영상점으로 위치 보정하는 기술을 개발하였다. 본 논문에서 적용된 보정 기술은 컴퓨터비젼분야, 제어계측분야에서 광범위하게 사용되고 있는 어안렌즈의 왜곡보정을 실시하여 영상을 보정하는데 목적이 있다. 이렇게 보정된 어안렌즈 영상은 실내 위치추적 및 모니터링 분야에 사용되고 있는 어안렌즈영상에 정확도 향상에 기여할 수 있으리라 예상된다. 또 본 논문에서는 렌즈 보정기술의 효율성을 높이기 위해서 단영상 왜곡보정 프로그램 및 다수 영상 왜곡 보정 프로그램을 구현하였다. 단영상 프로그램은 로봇의 대략 생산체제를 위해 구현하였으며, 다수영상 프로그램은 사용자 입장에서 구현하였다.

• Journal of The Korean Astronomical Society
• /
• v.37 no.4
• /
• pp.179-184
• /
• 2004

We have developed a wide-field imaging camera system, called WICZO, to monitor light of the night sky over extended period. Such monitoring is necessary for studying the morphology of interplanetary dust cloud and also the time and spatial variations of airglow emission. The system consists of an electric cooler a CCD camera with $60\%$ quantum efficiency at 500nm, and a fish-eye lens with $180^{\circ}$ field of view. Wide field imaging is highly desired in light of the night sky observations in general, because the zodiacal light and the airglow emission extend over the entire sky. This paper illustrates the design of WICZO, reports the result of its laboratory performance test, and presents the first night sky image, which was taken, under collaboration with Byulmaro Observatory, on top of Mt. Bongrae at Yongweol in January, 2004.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.1 no.2
• /
• pp.127-134
• /
• 1999

This study was performed to obtain the basic data to present rational silvicultural tending plan. It makes these widely distributed pine-oak mixed stand and each of pure stand in middle province on object of this study and do comparative analysis of light condition about stand parameter and natural regeneration according to each slope(north, west and south) conditions of location in central part of South Korea. Sample plots for pine-oak mixed stand and pine and oak pure stand were established on each of southern, northern and western slopes based upon site and growth conditions of the slope. Sample plot was a circle of 0.05ha with a diameter of 25.24 m. A sample plot has between 30 and 40 tree in it. Total 23 sample plots were established; 9 pure pine stands, 8 pine-oak mixed stands. and 6 pure oak stands across lower, middle, upper parts of slopes. Relative light intensity within a stand was' measured by crown- photo(fish-eye lens; 180$^{\circ}$) system through fish-eye lens and by comparing each plot with the denuded through PAR-sensor. The crown closure ratio of pure pine stand (75%) shows much lower than that of mixed stand (90.9%) and pure oak stand (93%). The relative light intensity within a stand showed an opposite result. The crown closure of mixed stands tended to become gradually low as the slope moves from the north to the south, but the relative light Intensity within the stand tended to rise. By analyzing the relationship between the relative light intensity within a stand and stand parameter, light intensity within a stand tended to decrease as the diameter and N/ha increase. Number of oak seedlings and light intensity within a stand is in a straight-line regression relation. In particular, the number of oak seedlings was the highest in mixed stands on the southern slope. But no single pine seedling was found. The unfavorable conditions of l0cm thick litter layer and low relative light intensity in a stand (ranging between 4% and 8%) is considered to prevent pine seeds from germinating.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.38 no.5
• /
• pp.12-20
• /
• 2010

The purpose of this study is to evaluate human thermal comfort by spatial structure and to explore solutions to improve the thermal environment of a small urban space. The study site was Korea University campus. Thermal conditions were measured to evaluate the quality of the thermal environment in each type of space within the study site. Micrometeorology measurements, analysis of space characteristics for using fish-eye lens photography, and thermal comfort modeling through the use of collected meteorological data, such as temperature and humidity, were performed. Results showed that the level of thermal comfort for humans differs depending on the types of space within the study site. Thermal comfort is better in open spaces than enclosed in the aspect of radiative mean temperature, Predicted Mean Vote(PMV), and Physiologically Equivalent Temperature(PET). This fact is probably due to shadows or buildings or trees that may block solar radiation. Thus, it is necessary to consider the spatial arrangements of buildings and trees to enhance openness and ventilation in the space. Paving materials and exterior building materials should also be selected to lower the radiant temperature. Given these results, a quantitative evaluation on human thermal comfort could propose a way to plan user comfortable small urban spaces. Study methods used and results provided in the study can promote a better way for urban space planning direction to improve environmental quality.