• Journal of radiological science and technology
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• v.27 no.4
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• pp.49-54
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• 2004

Purpose : To valuate the usefulness of mammographic image by using phantom 1,2 to controls the enhancement of image quality. Procedure : Set up same equipments for experiment (all the qualification must be the same). Control group and 4 other experiment the developing mammographys by using the image system with film/intensifying screen and distribute marks on each test objects of phantom 1, 2. Result : The results of the experiment using phantom 1, 2 on control group and 4 others are : 1. phantom 1's valuation with 3 items. - control group received 29 out of 32 - group A received 25 - group B received 16 - group C received 11.5 - group D received 28.5 The evaluation shows that the system has proved to display excellent image quality except group B and C. 2. Phantom 2's valuation with 4 items. - control group received 38 out of 38 - group A received 30 - group B received 16 - group C received 12.5 - group D received 38 Even with phantom 2, group B and C has displayed poor image quality. Conclusion : Both experiments using phantom 1 and 2 have shown that the most strong factor that control and influence the image quality are the filming equipments. Especially, the developing system has most powerful influence above all.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.1
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• pp.1-13
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• 1994

The terrestrial phetogrammetry has the relative convenience of selecting the site of photo station in contrast with the aerial photogrammetry, and the flexibility in accuracy prediction of object point positioning. So it has the advantage in designing optimum photo taking system which can fulfill the required accuracy. For the convergent photos which are frequently used for the monitoring of cultural assets and ground facilities, almost all of the traditional studies for the optimum photo condition, both in theoretical or experimental, are basically depend on the symmetrical configuration at the normal direction to the center of the object. However, in many cases the surroundings of the object do not allow the normal photo direction or sufficient convergent angle, even more the object features are not always be seen as one panel like planar. In this paper, the accuracy variation of convergent photos for the multi-planar objects, which are composed by some orthogonal planes, are investigated to establish the optimum photo condition. The results of the accuracy analysis for the photo direction, convergent angle, as well as the object feature are expected to be utilized in system design of geometric configuration of convergent photos, which are adequate for the accurate monitoring of the objects, such as culural assets, facilities, precision instruments, deformation surveying, etc.

• Tuberculosis and Respiratory Diseases
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• v.59 no.4
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• pp.356-360
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• 2005

Background : This study examined the clinical utility of using indirect chest radiography during a physical examination of new conscripts for determine the presence of pulmonary tuberculosis. Methods : Over an eight-month period, this study examined 25386 people who underwent a physical examination after conscription. The abnormal findings on mass miniature radiography were followed-up using direct chest radiography. The positive predictive value of mass miniature radiography and direct chest radiography was compared. The incidence, degree of infiltration and clinical outcome of active pulmonary tuberculosis were also evaluated during a follow-up examination. Results : The positive rate of mass miniature radiography was 1.19% (n=302). Various lesions were identified: Parenchymal lesions (n=109), mediastinal lesions (n=6), cardiovascular lesions (n=45), pleural lesions (n=49), bony lesions (n=90) and miscellaneous lesions (n=7). The incidence of active pulmonary tuberculosis by mass miniature radiography was 0.26% (n=67). The first diagnosis was made in 50 people; active pulmonary tuberculosis (n=42), pneumonia (n=1), a mediastinal mass (n=1), a rib fracture (n=2) and a pneumothorax (n=4). Most cases of active pulmonary tuberculosis were mildly infiltrated and either improved or were cured by the follow-up examination. Conclusion : Although mass miniature radiography in a physical examination after conscription has limitations, but it is a useful means for detecting the presence of early disease, particularly in active pulmonary tuberculosis.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.613-620
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• 2017

Planning dose must be delivered accurately for radiation therapy. Also, It must be needed accurately setup. However, patient positioning images were need for accuracy setup. Then patient positioning images is followed by additional exposure to radiation. For 45 points in the phantom, we measured the doses for 6 MV and 10 MV photon beams, OBI(On Board Imager) and CBCT(Conebeam Computed Tomography) using OSLD(Optically Stimulated Luminescent Dosimeter). We compared the differences in the cases where posture confirmation imaging at each point was added to the treatment dose. Also, we tried to propose a photography cycle that satisfies the 5% recommended by AAPM(The American Association of Physicists in Medicine). As a result, a maximum of 98.6 cGy was obtained at a minimum of 45.27 cGy at the 6 MV, a maximum of 99.66 cGy at a minimum of 53.34 cGy at the 10 MV, a maximum of 2.64 cGy at the minimum of 0.19 cGy for the OBI and a maximum of 17.18 cGy at the minimum of 0.54 cGy for the CBCT.The ratio of the radiation dose to the treatment dose is 3.49% in the case of 2D imaging and the maximum is 22.65% in the case of 3D imaging. Therefore, tolerance of 2D image is 1 exposure per day, and 3D image is 1 exposure per week. And it is need to calculation of separate in the parallelism at additional study.

• Journal of Veterinary Clinics
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• v.28 no.5
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• pp.510-515
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• 2011

This study was performed to quantitatively assess the normal lung volume and density according to the position by multi-detector computed tomography (MDCT) in dogs. Helical CT of the thorax was performed on 4 different positions with dorsal, left lateral, right lateral and ventral recumbency in 6 Pekingese and 6 Maltese dogs. During CT scanning, dogs were kept hyperventilated. Through the 3-dimensional reconstruction of CT images, the lung parameters were measured as the volume and density of the left, right including accessory lobe, and total lung. 3D images represented the different lung shape between Pekingese and Maltese dogs. Their difference of total lung volume and total lung density was not significant on the each position in both breeds. Right lung volume was significantly higher than left. The difference of left and right volume was $66.91{\pm}25.1$ ml. Linear relationship was shown between body weight and lung volume of ventral recumbency position. The dependent lung had higher density and lower volume than nondependent lung in both breed dogs. The volume of nondependent lung was not changed compared with the volume on ventral or dorsal recumbency. The total lung volume measured with MDCT is correlated with the lung density, and the lung density is useful to predict the normal total lung volume.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1379-1391
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• 2020

UAV in the agricultural application are capable of collecting ultra-high resolution image. It is possible to obtain timeliness images for phenological phases of the crop. However, the UAV uses a variety of sensors and multi-temporal images according to the environment. Therefore, it is essential to use normalized image data for time series image application for crop monitoring. This study analyzed the variability of UAV reflectance and vegetation index according to Aviation Image Making Environment to utilize the UAV multispectral image for agricultural monitoring time series. The variability of the reflectance according to environmental factors such as altitude, direction, time, and cloud was very large, ranging from 8% to 11%, but the vegetation index variability was stable, ranging from 1% to 5%. This phenomenon is believed to have various causes such as the characteristics of the UAV multispectral sensor and the normalization of the post-processing program. In order to utilize the time series of unmanned aerial vehicles, it is recommended to use the same ratio function as the vegetation index, and it is recommended to minimize the variability of time series images by setting the same time, altitude and direction as possible.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.499-505
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• 2022

Recently, the metaverse has been receiving a lot of attention. Metaverse means a virtual space, and various events can be held in this space. In particular, 360-degree video, a format optimized for the metaverse space, is attracting attention. A 360-degree video image is created by stitching images taken with multiple cameras or lenses in all 360-degree directions. When shooting a 360-degree video, a variety of shooting equipment, including a shooting staff to take a picture of a subject in front of the camera, is displayed on the video. Therefore, when shooting a 360-degree video, you have to hide everything except the subject around the camera. There are several problems with this shooting method. Among them, lighting is the biggest problem. This is because it is very difficult to install a fixture that focuses on the subject from behind the camera as in conventional image shooting. This study is an experimental study to find the optimal angle for 360-degree images by adjusting the angle of indoor lighting. We propose a method to record 360-degree video without installing additional lighting. Based on the results of this study, it is expected that experiments will be conducted through more various shooting angles in the future, and furthermore, it is expected that it will be helpful when using 360-degree images in the metaverse space.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.123-129
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• 2023

The purpose of this study was to analyze differences in imaging quality and dose difference between intra-venous (IV) and intra-arterial (IA) liver dynamic computed tomography (CT). Herein, retrospective, blinded analysis was conducted to analyze signal-to-noise and contrast-to-noise ratios in cases of patients who underwent IV or IA liver dynamic CT for transarterial chemoembolization (TACE), an interventional procedure for hepatocellular carcinoma. The dose length product (DLP) value stored in Picture Archive and Communication System (PACS) was used to calculate the effective dose and thereby compare differences in the dose between the two methods. The mean liver and spleen signal to noise ratio (SNR) was greater in IV-liver dynamic CT than in IA-liver dynamic CT; however, contrast to noise ratio (CNR) was higher in IA-liver dynamic CT than in IV-liver dynamic CT. However, there were no differences in DLP and effective dose between the two methods. In conclusion, our findings showed that IA-liver dynamic CT showed a similar effective dose and superior CNR compared with IV-liver dynamic CT. Further studies must analyze 3D angiography CT of the hepatic artery to clearly distinguish the feeding artery, which is the essential step in interventional procedures for hepatocellular carcinoma.

• The Journal of the Korea Contents Association
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• v.15 no.7
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• pp.93-105
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• 2015

Upon ruling that two photographs of "Solsum(located in Samchuk city)" are not substantially similar, issues on the level of protection for the copyrighted photographs expecially on landscape, which appearance could be similar whoever takes, were raised. Accordingly, this study summarizes and suggests the standards of expression differentiating from idea on photographic works. The results are as such. Elements of expression on photographs are positioning of subject, framing, selection of camera angle, control of light's direction and quantity, length of exposure, speed of shutter, timing or posing of the shutter. kinds of emulsion, methods of development, and any other methods of creative and characteristic photography. On the other hand, elements of ideas of photographic works are theme, concept, feeling, appearance of objects, time or season of taking a picture, vantage point, choice of horizontal or vertical angle, etc. As a result, this study reconfirms that copyright law entitles photographers to copyright as to their minimal degree of creativity, not as to their sweat of brows.

• Journal of Korean Society for Geospatial Information Science
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• v.3 no.1 s.5
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• pp.105-113
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• 1995

Three-dimensional landscape map is very useful in terrain analysis as it looks like real shape of terrain. When three-dimensional landscape map is needed, landscape photos achieved at a position of high elevation or by airplane are generally used. But, this approach can not fully satisfy the user's need to get pictures from various view points. In addition, because photos have some geometric displacement caused by the principle of central projection of camera, it is hard to get accurate locations from the photo. This paper aims to get three-dimensional landscape map similar to real terrain feature from vertical stereo aerial photos by digital photogrammetric techniques. This approach can provide a very useful data for three-dimensional terrain analysis as a function of Geo-Spatial Information System.