• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.3
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• pp.263-269
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• 2000

As the accuracy of digital photogrammetry is restricted by the resolution of image to be used, it is axiomatic that the resolution of image should be improved. As for the method to constitute hardware with CCD sensor that capacity was expanded or the method to acquire the image of high resolution by deciding the quantity of sub-pixel in advance through moving sensor, the price is expensive. This study tries to enhance the resolution of low resolution image by acquiring the image with the digital camera that the price is cheap and deciding shifts and rotations through matching multiple digital image by means of least square method. As the result of study, the resolution of digital image was improved greatly. So, not only the digital photogrammetry which has the competitive power of price economically is possible in the future but also the application is expected widely.

• Spatial Information Research
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• v.7 no.1
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• pp.1-12
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• 1999

The DTM(Digital Terrain Model) in GIS(Geographical Information System) shows the elevation from interpolation using data points surveyed. In panoramic flat landform, pixel size, resolution of source data may not be the problem in using DTM However, in mountainous landform like Korea, appropriate resolution accuracy of source data are important factors to represent the topography concerned. In this study, the difference in contour interval of source data, the resolution after interpolation, and different data structures were compared to figure out the accuracy of slope calculation using DTM from the topographic maps of Togyusan National Park Two types of GIS softwares, Idrisi(grid) ver. 2.0 using the altitude matrices and ArcView(TIN) ver. 3.0a using TIN were used for this purpose. After the analysis the conclusions are as follows: 1) The coarser resolution, the more smoothing effect inrepresenting the topography. 2) The coarser resolution the more difference between the grid-based Idrisi and the TIN-based ArcView. 3) Based on the comparison analysis of error for 30 points from clustering, there is not much difference among 10, 20, 30 m resolution in TIM-based Airview ranging from 4.9 to 6.2n However, the coarser resolution the more error for elevation and slope in the grid-based Idrisi. ranging from 6.3 to 10.9m. 4) Both Idrisi and ArcView could net consider breaklines of lanform like hilltops, valley bottoms.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.199-201
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• 2010

본 논문에서는 광케이블과 소형렌즈를 검사하기 위한 고해상력 투영검사기를 개발하였다. 개발된 고해상력 투영검사기는 30V/7A 전원장치에서 할로겐램프를 연결하여 원격장치로 램프의 밝기를 조절한다. 개발된 고해상력투영검사기는 관련기술을 확보하였고 수입대체효과를 가져올 수 있다.

• Progress in Medical Physics
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• v.3 no.2
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• pp.67-81
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• 1992

Lots of physical phenomena which deteriorate the faithfulness of radiological images exist. The most common types of degradation are a loss of resolution and an increase in noise. This article deals with resolution. factors that influence it. and its characterisation. The problem of resolution failure due to a generic blurring phenomenum is described diagramatically and mathematically. for both one dimensional and two dimensional signals. The definition of the point spread function. the line spread function. the convolution integral and the modulation transfer function are made. The concept of frequency domain operations using the Fourier Transform is also discussed.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.309-314
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• 2012

Nowadays, digital Radiography (DR) systems are widely used in clinical sites and substitute the analog-film x-ray imaging systems. The resolution of DR images depends on several factors such as characteristic contrast and motion of the object, the focal spot size and the quality of x-ray beam, x-ray scattering, the performance of the DR detector (x-ray conversion efficiency, the intrinsic resolution). The DR detector is composed of an x-ray capturing element, a coupling element and a collecting element, which systematically affect the system resolution. Generally speaking, the resolution of a medical imaging system is the discrimination ability of anatomical structures. Modulation transfer function (MTF) is widely used for the quantification of the resolution performance for an imaging system. MTF is defined as the frequency response of the imaging system to the input of a point spread function and can be obtained by doing Fourier transform of a line spread function, which is extracted from a test image. In clinic, radiologic technologists, who are in charge of system maintenance and quality control, have to evaluate or make routine check on their imaging system. However, it is not an easy task for the radiologic technologists to measure MTF accurately due to lack of their engineering and mathematical backgrounds. The objective of this study is to develop and provide for radiologic technologists a medical system imaging evaluation tool, so that they can measure and quantify system performance easily.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.5
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• pp.485-492
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• 2012

Today, a digital airborne imaging sensor plays an important role in construction of the numerous National Spatial Data Infrastructure. However, an appropriate quality assesment procedure for the acquired digital images should be preceded to make them useful data with high precision and reliability. A lot of studies therefore have been conducted in attempt to assess quality of digital images at home and abroad. In this regard, many test fields have been already established and operated to calibrate digital photogrammetric airborne imaging systems in Europe and America. These test fields contain not only GCPs(Ground Control Points) to test geometric performance of a digital camera but also various types of targets to evaluate its spatial and radiometric resolution. The purpose of this paper is to present a method to verify the spatial resolution of the Intergraph DMC digital camera and its results based on an experimental field testing. In field test, a simple bar target to be easily identified in image is used to check the spatial resolution. Images, theoretically designed to 12cm GSD(Ground Sample Distance), were used to calculate the actual resolution for all sub-images and virtual images in flight direction as well as in cross flight direction. The results showed that the actual image resolution was about 0.6cm worse than theoretically expected resolution. In addition, the greatest difference of 1.5cm between them was found in the image of block edge.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.1-3
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• 2019

최근 선박의 대형화, 태풍 및 돌풍 등 급격한 자연환경의 변화, 한정된 정박지의 과밀 등으로 VTS 해역에서 선박 주묘가 자주 발생하고 있다. 선박의 주묘를 예측하기 위해서는 기상 조건에 의한 외력과 선박의 묘, 묘쇄 등 대항력의 정확한 비교, 현수부 및 파주부를 고려한 주묘 발생 가능 시점 예측 등의 노력이 요구된다. 본 연구에서는 VTS 관제 구역에서의 주묘 사고 사례 분석을 통하여 주묘 위험성 판단 프로그램을 검증하고, 관제 시스템에서 활용을 위한 시스템 개선 방안을 제안하고자 한다. 향후 관제 시스템의 주묘 위험성 판단 기능 도입을 통하여 주묘 사고의 예방 및 조기 대응이 가능할 것으로 기대한다.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.395-403
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• 2022

Flat-panel detector (FPD) used in digital radiographic imaging systems was used to perform a quantitative power spectrum evaluation as a result of the thickness change of polymethyl methacrylate (PMMA), a tissue equivalent. As the PMMA thickness increases with the resolution-chart phantom image, the effect of the scattering line increases, indicating that the modulation characteristics decrease, and the image is bright. The results show that the noise of the image increases, and noise-power spectral images are obtained by Fourier transform to confirm by spatial frequency. Thus, it can be verified that the PMMA thickness and noise are proportional through the result of evaluating the change of resolution characteristics and representing the 2D noise-power spectrum as one-dimensional values by evaluating the change of scattering line with MTF as the PMMA thickness increases in the image.

• Journal of Korean Society for Geospatial Information Science
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• v.8 no.2 s.16
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• pp.61-69
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• 2000

Until now, the extraction of information on geographic features and the compilation of maps from satellite imagery has had many limitations because of its lower resolution compared to aerial photos to the recent. However, it is expected that the availability of high resolution satellite imagery whose spatial resolution is about 1m will reduce such limitations. Currently, a compilation of national-wide digital base maps is going on to construct the National Geographic Information Systems in Korea. It will be used for many application field of the social welfare. Therefore, in this study, we suggest that satellite imagery can help it and we have experimented on the possibility of detecting and interpreting geographic data using satellite imagery of various spatial resolutions. The interpretability and detectability of 46 features in 6 categories was experimented with 6 kinds of images of different resolutions. As a subsequent procedure, we have performed the fractal analysis for a quality test of the texture information. Through the fractal analysis, we could show that texture information and probability of discrimination increases as the spatial resolution of the image increases. Based on the results of this experiment, we could suggest the possibility of the renewal and construction of the National-wide Geographic Information Systems database using satellite imagery, as well as of examining appropriate spatial resolutions for objects of interest.

• Maritime Security
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• v.2 no.1
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• pp.43-70
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• 2021

This study started from questioning our general view that the Japan Maritime Self-Defense Force (JMSDF) is a natural result of Japan being a prosperous and island country. Japan's naval power collapsed after World War II. The initial power of the JMSDF, founded in 1954, was very small and not different from the Republic of Korea Navy (ROKN), mostly consisting of ships given by or borrowed from the US. Although growing into the world's second-largest economy and the geographical characteristics of an island nation acted as an opportunity to increase naval forces, there were also difficulties in the early stage, such as a temporary severance with the Japanese Navy, strategic thinking centered on land forces, and an economic crisis caused by the oil crisis. As a result, the JMSDF has become a world-class naval power and is developing into a four helicopter carrier operating system, which may change the basic concept of exclusive defense. There are various factors behind the growth of Japan's naval power, but this study explores how to develop Korean naval forces by analyzing how Japan developed their escort fleet, the core of the JMSDF, focusing on the eight (艦)-eight (機) fleet system, which was the basic logic behind building the JMSDF.