• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.432-435
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• 2002

We have developed and proposed the heavy ion CT system which consists of fluorescent screen and CCD camera equipped with image intensifier. In our system, we have measured the residual range of particles that passed a phantom and reconstructed the CT image for the distribution of relative stopping power by filtered back projection method with Shepp '||'&'||' Logan filter. The heavy ion $\^$12/C accelerated up to 400 MeV/u by HIMAC (Heavy Ion Medical Accelerator in Chiba) was used. Intensity of the beam output changes like macro pulse, the period being 3.3 sec and the width being 2 sec. The series of data was acquired in synchronizing with the pulse, leading to the improvement of S/N in the CT image. The fundamental performance was experimentally evaluated in the proposed system. The spatial resolution was estimated to be about 1 mm and the density resolution (electron density referred to water) to be about 0.01.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.3
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• pp.229-236
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• 2003

This study recorded an object using a digital video recorder, and then tried to estimate 3-D positional information and to reconstruct an image. Firstly, the accuracy of measurement results from a video recorder was evaluated and tested for an applicability, then it applied to a real object to construct 3-D digital model. This study assumed that there is no lens distortion in a video recorder, and all bundles should precisely pass through the projection center of a lens. The image size for orientations is determined by the size of CCD chip and the number of pixels. The average squared error from the result by a digital video recorder and that by triangular survey from 1-second theodolite shows 0.0173m error in x,y coordinates. Without knowing the accurate information on the lens distortion and the coordinates of the projection center, this study reasonably produces acceptable results in the reconstruction of 3-D model. In consequence, this study found that the image from a digital video camera can be reconstructed 3-D model only from the information on a camera type.

• Journal of Sensor Science and Technology
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• v.11 no.2
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• pp.93-101
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• 2002

The quality of agricultural products is classified with various factors which are measured and determined by destructive and/or nondestructive method. NIR spectrum analysis method is used to determine internal qualities such as a brix and an acidity. CCD color camera is used to measure external quality like color and a size of fruit. Today, nondestructive methods are widely researched. The quality and the grade of fruit loaded into a cup automatically and measured in real time by camera and NIR system is determined by infernal and external factors. This paper proposes modified boundary tracking algorithm which detects the contour of fruit's color image and make chain code faster than conventional method. The chain code helps compute a size of fruit image and find multiple loading of a fruit in single cup or fruit between two cups. The designed classification system sorts a citrus at speed of 8 fruit/s, with evaluating a brix, an acidity and a size grade.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.531-541
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• 2017

Realistic videos using multi-view videos are created so that the contents shown on multi-view displays or screens look realistic. These images have been mostly used for special videos for exhibition, but, recently, systems such as Screen X have given rise to multi-view images as a format for storytelling contents such as movies. This study used HD-level broadcasting digital video camera with three zoom lenses for shooting wide to close-up shots focusing on a person, in the same way as Screen X, and identified and analyzed problems found during multi-view image registration correction. The results of this study suggested, provided the shooting technique and equipment are improved, the multi-view format can be used for conveying stories and information. Future research will need to investigate and supplement relevant techniques that will enable production of high-quality multi-view image contents by using a cinema-grade camera with standard lenses, instead of using broadcasting-grade zoom lenses.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.2
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• pp.13-19
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• 2012

The techniques of 3d image processing have broadly used in the areas including movies, games, performances, exhibitions. In addition, increasing demands for practical uses have gradually extended to the areas of architecture, medicine, nuclear power plant. However, dominant techniques for 3d image processing seem to depend on multi-camera in which two stereo images are merged into one image. Also the pipeline has limitations to provide real-time 3d viewer in ubiquitous computing. It is not able to be applicable onto most general screens as well. In addition, the techniques can be utilized for the real-time 3d game play without a particular monitor or convertor. Hence, the research presented here is to aim at developing an efficient real-time 3d viewer using only mono camera which do not need post processing for editing as well.

• The KIPS Transactions:PartB
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• v.14B no.5
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• pp.351-360
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• 2007

Video Completion refers to a computer vision technique which restores damaged images by filling missing pixels with suitable color in a video sequence. We propose a new video completion technique to fill in image holes which are caused by removing an unnecessary object in a video sequence, where two objects cross each other in the presence of camera motion. We remove the closer object from a camera which results in image holes. Then these holes are filled by color information of some others frames. First of all, spatio-temporal volumes of occluding and occluded objects are created according to the centroid of the objects. Secondly, a temporal search technique by voxel matching separates and removes the occluding object. Finally. these holes are filled by using spatial search technique. Seams on the boundary of completed pixels we removed by a simple blending technique. Experimental results using real video sequences show that the proposed technique produces new completed videos.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.6
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• pp.70-81
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• 2001

This paper presents a 3D face modeling method using a CCD camera and a projector (LCD projector or Slide projector). The camera faces the human face and the projector casts white stripe patterns on the human face. The 3D shape of the face is extracted from spatial and temporal locations of the white stripe patterns on a series of image frames. The proposed method employs region segmentation and multi-beam techniques for efficient 3D modeling of hair region and faster 3D scanning respectively. In the proposed method, each image is segmented into face, hair, and shadow regions, which are independently processed to obtain the optimum results for each region. The multi-beam method， which uses a number of equally spaced stripe patterns, reduces the total number of image frames and consequently the overall data acquisition time. Light beam calibration is adopted for efficient light plane measurement, which is not influenced by the direction (vertical or horizontal) of the stripe patterns. Experimental results show that the proposed method provides a favorable 3D face modeling results, including the hair region.

• Aerospace Engineering and Technology
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• v.9 no.1
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• pp.28-34
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• 2010

All pixels of image sensor do not react uniformly when the light of same radiance enters into the camera. This non-uniformity has a direct influence on the image quality. However we can overcome it by calibration process under the special test-setup. Usually it is used the algorithm to get the correction coefficients under the specific illumination condition. But, this method has drawback in the very low or very high illumination due to pixel non-linearity. This paper describes the robust algorithm, which calculates the correction coefficients based on the pixel non-linearity model, against thew hole radiance. The paper shows the non-uniformity test results with the own camera and the specified test equipments as well. The results shows the best performance over the entire radiance when this method is applied.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.6
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• pp.536-541
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• 2015

In this paper, we propose a the image-based automatic flight control system for the mini drone. Automatic flight system with a camera on the ceiling and markers on the floor and landing position is designed in an indoor environment. Images from the ceiling camera is used not only to recognize the makers and landing position but also to track the drone motion. PC sever identifies the location of the drone and sends control commands to the mini drone. Flight controller of the mini drone is designed using state-machine algorithm, PID control and way-point position control method. From the, The proposed automatic flight control system is verified through the experiments of the mini drone. We see that known makers in environment are recognized and the drone can follows the trajectories with the specific ㄱ, ㄷ and ㅁ shapes. Also, experimental results show that the drone can approach and correctly land on the target positions which are set at different height.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.138.2-138.2
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• 2012

Cave on the Moon is considered as the most appropriate place for human to live during the frontier lunar exploration. While the lava flows, the outer crust gets cooled and solidified. Then, the empty space is remained inside after lava flow stops. Such empty space is called the lava caves. Those lava tubes on the Earth are formed mostly by volcanic activity. However, the lava tubes on satellite like Moon and planet like Mars without volcanic activity are mostly formed by the lava flow inside of the crater made by large meteorite impact. Some part of lava tube with collapsed ceiling appears as the entrance of the cave. Such area looks like a deep crater so called a pit crater. Four large pit craters with diameter of > 60 m and depth of > 40 m are found without difficulty from Kaguya and LRO mission image archives. However, those are too deep to use as easily accessible human frontier base. Therefore, now we are going to identify some smaller lunar caves with accessible entrances using LRO camera images of 0.5 m/pixel resolution. Earth's lava caves and their entrances are well photographed by surface and aerial camera in immense volume. Thus, if the image data are sorted and archived well, those images can be used in comparison with the less distinct lunar cave and entrance images due to its smaller size. Then, we can identify the regions on the Moon where there exist caves with accessible entrances. The database will be also useful in modeling geomorphology for lunar and Martian caves for future artificial intelligence investigation of the caves in any size.