안개가 포함된 영상에서의 색 왜곡 특성 분석

김정엽 아이씨티플랫폼학회 2023 JOURNAL OF PLATFORM TECHNOLOGY Vol.11 No.6

In this paper, the color distortion in images with haze would be analyzed. When haze is included in the scene, the color signal reflected in the scene is accompanied by color distortion due to the influence of transmittance according to the haze component. When the influence of haze is excluded by a conventional de-hazing method, the distortion of color tends to not be sufficiently resolved. Khoury et al. used the dark channel priority technique, a haze model mentioned in many studies, to determine the degree of color distortion. However, only the tendency of distortion such as color error values was confirmed, and specific color distortion analysis was not performed. This paper analyzes the characteristic of color distortion and proposes a restoration method that can reduce color distortion. Input images of databases used by Khoury et al. include Macbeth color checker, a standard color tool. Using Macbeth color checker's color values, color distortion according to changes in haze concentration was analyzed, and a new color distortion model was proposed through modeling. The proposed method is to obtain a mapping function using the change in chromaticity by step according to the change in haze concentration and the color of the ground truth. Since the form of color distortion varies from step to step in proportion to the haze concentration, it is necessary to obtain an integrated thought function that operates stably at all stages. In this paper, the improvement of color distortion through the proposed method was estimated based on the value of angular error, and it was verified that there was an improvement effect of about 15% compared to the conventional method.

주변부 상의 왜곡을 보정한 모바일 광각 카메라의 광학적 설계

김세진,정혜정,임현선 한국안광학회 2013 한국안광학회지 Vol.18 No.4

Purpose: This study was to design wide angle mobile camera corrected optical distortion for peripheral area,which were reduced optical distortion and TV distortion by using 4 aspherical lenses. Methods: The optical design was satisfied with ±1% optical distortion in viewing angle of 95o and total length of optical system was less than 4.5 mm which was considering a thickness of mobile camera. 1/3.2 inch (5M) CCD sensor was used in the optical system and set design condition to satisfy MTF which was over than 20% in 140 lp/mm. Results:Optimized wide angle mobile camera showed ±1% optical distortion in full field of 95o viewing angle and TV distortion was 0.46% so that distortion of peripheral area was reduce. MTF showed over than 20% in every field. Ray aberration and astigmatism were small amount so that it showed stable performance. Conclusions: Obtain wider and clearer view which is reduced image distortion of surrounding area via optical method in wide angle mobile camera which has wider view angle than current mobile camera. And it was able to fix a demerit when it occurred via software correction. It is able to apply to study of camera which is related to spectacles. 목적: 4매의 비구면 렌즈를 사용하여 optical distortion과 TV distortion을 감소시켜 주변부 상의 왜곡을 줄인 광각의 모바일 카메라를 설계하였다. 방법: 광학적 설계는 화각 95o에서 ±1%내의 optical distortion을 만족하도록 하였으며, 광학계 전체길이는 모바일 카메라의 두께를 고려하여 4.5 mm 이내로 하였다. 센서는 1/3.2"의 5M급 CCD를사용하였으며 MTF는 140 lp/mm에서 20% 이상을 만족하도록 설계 조건을 설정하였다. 결과: 최적화 설계된 모바일 광각 카메라는 화각 95o의 full field에서 optical distortion은 모든 field에서 ±1%내의 결과를 보였으며 TV distortion도 0.46%로 주변부 상의 왜곡이 감소되었다. MTF 성능은 모든 field에서 20%이상으로 나타났다. 광선수차와 비점수차 모두 적은 양으로 안정된 성능을 보였다. 결론: 기존의 모바일 카메라의 화각보다 더 큰 화각을 갖는 광각의 모바일 카메라의 distortion을 광학적으로 개선하여 주변부의 상의 왜곡을 감소시켜 보다 쾌적한 넓은 시야를 얻을 수 있었으며 소프트웨어로 보정할 때 발생하는 단점을 보완할 수 있었다. 이는 안경과 접목되는 카메라의 연구에 활용될 수 있으리라 사료된다.

중앙경선 설정에 따른 세계지도 투영법의 상대적 적합도 평가: 로빈슨 도법과 빈켈 트리펠 도법의 비교

김용민,이상일 한국지도학회 2026 한국지도학회지 Vol.26 No.1

본 연구는 중앙경선의 선택이 육지부의 평균 투영 왜곡도와 투영법의 상대적 적합도에 미치는 영향을 로빈슨 도법과 빈켈 트리펠 도법의 비교를 통해 실증적으로 분석하였다. 이를 위해 티소의 지시타원을 기반으로 각도, 면적, 축척의 국지적 왜곡도를 정의하고, 수치적분을 통해 육지부 전체의 평균 왜곡도로 확장하였다. 또한 2.5° 간격의 경위도 격자망과 중앙경선 차원을 결합한 3차원 계산 체계를 구축하여, 중앙경선 변화에 따른 왜곡도의 분포를 체계적으로 산출하였다. 분석 결과, 두 도법 모두에서 왜곡도는 중앙경선의 설정에 의존하는 것으로 나타났다. 각도 왜곡의 경우 동경 30° 부근에서 최소, 서경 130° 부근에서 최대를 보이며, 일부 구간을 제외하면 대부분의 중앙경선에서 로빈슨 도법이 빈켈 트리펠 도법보다 우세하였다. 반면 면적 왜곡에서는 중앙경선의 위치와 무관하게 빈켈 트리펠 도법이 일관되게 우세하였으며, 두 왜곡 범주는 서로 상반된 공간적 분포를 보였다. 이러한 차이는 각 투영법이 지니는 고유한 왜곡의 공간적 구조와, 중앙경선의 변화에 따라 달라지는 수륙 분포의 재배치가 결합된 결과로 해석된다. 특히 중앙경선의 이동에 따라 육지부가 지도 중앙 또는 외곽으로 이동하면서 평균 왜곡도에 대한 기여 구조가 달라지는 점이 핵심적인 요인으로 작용한다. 이러한 분석을 바탕으로 중앙경선을 동경 150°로 설정한 경우를 평가한 결과, 로빈슨 도법은 각도 왜곡에서 상대적 개선을 보이는 반면 면적 왜곡은 증가하여 두 왜곡 속성 간 상충이 발생하는 것으로 나타났다. 그러나 각도와 면적 왜곡의 균형을 고려하되 각도 왜곡의 영향력이 더 크다는 평가 기준을 적용하면, 로빈슨 도법의 상대적 적합성은 본초자오선을 중앙경선으로 설정한 경우에 비해 높아지는 것으로 해석할 수 있다. 본 연구는 중앙경선을 투영 왜곡 분석의 핵심 변수로 도입함으로써, 투영법의 성능을 보다 일반화된 틀에서 재평가할 수 있는 방법론을 제시하였다는 점에서 의의를 가진다. This study investigates how the choice of central meridian affects mean projection distortion over land and the relative suitability of map projections, through a comparative analysis of the Robinson and Winkel Tripel projections. Local distortions—angular, areal, and scale—are defined using Tissot’s indicatrix and extended to mean distortions over global land areas via numerical integration. A three-dimensional computational framework is constructed by combining a latitude–longitude grid with a central meridian dimension, enabling systematic evaluation of distortion patterns across different meridians. The results show that distortion levels in both projections depend on the choice of central meridian. Angular distortion reaches a minimum near 30°E and a maximum near 130°W, with the Robinson projection outperforming the Winkel Tripel projection across most meridians except within a limited range. In contrast, areal distortion consistently favors the Winkel Tripel projection regardless of the meridian, and exhibits a spatial pattern opposite to that of angular distortion. These differences can be explained by the interaction between the intrinsic spatial distribution of distortion in each projection and the redistribution of landmasses caused by shifts in the central meridian. In particular, changes in the relative position of land areas—whether concentrated near the center or the edges of the map—significantly influence the overall distortion metrics. Based on this framework, the case of setting the central meridian to 150°E is evaluated. Under this configuration, the Robinson projection shows a clear improvement in angular distortion but a deterioration in areal distortion, resulting in a trade-off between distortion types. However, when greater weight is assigned to angular distortion in accordance with commonly used evaluation criteria emphasizing visual naturalness, the relative suitability of the Robinson projection improves compared to the prime meridian case. This study highlights the central meridian as a critical analytical dimension and provides a generalized methodological framework for reevaluating projection performance under varying meridian configurations.

Research on Camera Calibration method Based on Eight Parameter Model

Yu Shuchun,Liu Shuang,Yu Xiaoyang 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.9

Camera calibration is the basis for realization of image distortion correction. Because the causes of image distortion are very complex, it has become a difficulty to correct image distortion with calibration results. In order to reduce the complexity of the existing distortion correction method, an eight parameters camera calibration model was proposed in this paper. In this model, eight parameters were used in describing radial distortion and tangential distortion. The experimental results show that the proposed method can be easily solved and correct distortion accurately.

딥러닝 기반의 2차원 이미지 왜곡 분류 및 이미지 각도 보정 시스템 개발

서창진,김선화,김유진,최수민 대한전기학회 2022 전기학회논문지 P Vol.71 No.3

When taking a picture with a camera, the distortion that is different from reality occurs due to wide-angle lenses and camera angles. In this paper, we propose an image distortion classification and calibration program that provides users with standard images before distortion by classification and calibrating distortion. The program automatically predicts camera parameters from a single input image and proceeds with calibration. Inputting the image, distortion image classification using deep learning (CNN) determines whether Wide-angle lens distortion and Camera-angle distortion exist. When it is determined that distortion exists, deep learning and OpenCV are used to calibrate the distortion state according to each image characteristic. As a result of the program operation, it was confirmed that the output image was calibrated similarly to the actual one, and more fine distortion calibration can be expected by finding distortions that were difficult to judge only with human eyes.

입구 압력 왜곡 형상에 따른 축류 압축기 성능 변화 연구

배성한,김수빈,김윤제 한국유체기계학회 2024 한국유체기계학회 논문집 Vol.27 No.6

The evolution of modern commercial turbofan engines has led to larger diameters, which enhance efficiency and reduce noise. However, this has also increased the likelihood of inlet pressure distortion, particularly due to crosswinds. Computational fluid dynamics (CFD) was used to examine the effects of inlet pressure distortion on the tip and hub of a NASA rotor 67 model. Performance metrics, including the total pressure ratio, adiabatic efficiency, surge margin, and operating flow range, were evaluated. Metrics declined linearly as the central angle of the tip distortion area increased. A linear decline in total pressure ratio and adiabatic efficiency was observed when the hub distortion angle was increased at a 90° tip distortion angle. Conversely, surge margin and operating flow range exhibited a peak at a hub distortion angle of 180°. In comparison to the absence of inlet distortion, surge margin and operating flow range were reduced to 42.19 % and 52.27 %, respectively, with a 90° tip inlet distortion, and recovered to 95.94 % and 102.49 % with an additional 180° hub inlet distortion. The study also revealed that tip pressure distortion resulted in the generation of a weak shock wave and an increase in entropy due to tip leakage flow. These effects were found to be mitigated by the introduction of additional hub pressure distortion with an appropriate central angle.

국가안보 정책결정과정에서 정보왜곡의 발생요인에 관한 연구: 2003년 미국의 이라크 WMD 정보판단을 중심으로

전태수 ( Jeon Tai-soo ) 한국정책연구원 2007 한국정책논집 Vol.7 No.-

The purpose of this study is to investigate causal factors of intelligence distortion in American national security policy making process. Even though adequate and timely intelligence is requisite for rational policy making, intelligence provided to policy makers are often distorted through the intelligence circulation process, thus limiting rational policy making. Most findings in previous studies are only by-products of researches in cognitive psychology, communication theories, organization behavior theories, etc. Moreover, it is difficult to conduct studies on the developing causes of intelligence distortion in the national security circulation policy because of characteristics of security and secrecy of intelligence process. Particularly, empirical studies on this matter are rarely available in Korea. Therefore, in order to evaluate this topic, I reviewed previous findings on intelligence distortion in various academic fields. Also, I conducted in-depth interviews and created questionnaires about intelligence distortion for Korean experts on the Weapons of Mass Destruction (WMD) policy of the U.S.A. to Iraq in 2003. Therefore, I developed a framework for research analysis using parameters derived from collection officer, analysis officer, gatekeepers, policy decision maker. I also set moderating variables that the openness of related intelligence, the redundancy of intelligence channels, uncertainty, and dependent variables derived from intelligence distortion in forms such as exaggeration, reduction, fabrication, omission, and procrastination. Previous researches focusing on the independent variables have not verified the national case and time factor which caused intelligence distortion. Accordingly, this was a new type of research method. In the result of the study, it has been verified that all variables such as independent variables, moderating variables, parameter etc. Utilization in previous researches was compelling factors in explaining direct and indirect affects towards intelligence distortion. By this study, it illustrated that the intelligence distortion is a serious problem that can cause a fatal loss in existence and prosperity of a nation by misleading policy makers to wrong policy making. Most intelligence distortion is created in the intelligence circulation process. However, after the study, it has been discovered that the president, the top policy maker, as well as chief governmental officials could have manipulated the intelligence. Therefore, it is safe to say that much intelligence distortion could be caused by the policy maker who lacked sufficient policy responses or used the intelligence for their own political purposes. If this is the case, we can conclude that both sides, users and producers, have to overcome intelligence distortion for efficient national policy making decisions.

사회지향성과 사회문화적 압력이 폭식행동에 미치는 영향: 섭식관련 인지왜곡의 매개효과

조성실,박기환 한국사회및성격심리학회 2013 한국심리학회지 사회 및 성격 Vol.27 No.1

The purpose of this study was to explore the relation among sociotropy, sociocultural pressure to thinness, cognitive distortion and binge eating in adolescent girls and to investigate whether cognitive distortion mediate that sociotropy and sociocultural pressures affect binge eating. For this purpose, a total of 551 female adolescent composed of 206 middle school girls and 345 high school girls were involved in the study and responded to the self-reported questionnaire. Revised Personal Style Inventory, Tripartite Influence Scale-Revised, The Mizes Anorectic Cognition Scale and Bulimia Test Revised were used to measure sociotropy, sociocultural pressures, cognitive distortion and binge eating. Mediated effect of cognitive distortion among sociotropy, sociocultural pressures and binge eating was verified using structural equation modeling. The results were as follows. First. adolescent girls discriminated into binge eating group and normal group according to the standard of Bulimia test revised scores. The result of compared two groups was that binge eating group have a significantly higher body mass index(BMI), sociotropy, and sociocultural pressures, cognitive distortion than normal group. Second, sociotropy, sociocultural pressure and cognitive distortion were related significantly to binge eating. Third, The result of mediated analysis were sociotropy, sociocultural pressure and cognitive distortion had a significant effect on binge eating behavior and sociotropy, sociocultural pressure fully mediating model of the cognitive distortion fitted the data. In other words, sociotropy and sociocultural pressure indirectly affect cognitive distortion and binge eating behavior by through cognitive distortion. Finally, the clinical implications and several limitations of the present study were discussed. 본 연구는 사회지향성, 날씬함에 대한 사회문화적 압력, 섭식관련 인지왜곡과 청소년 여학생의 폭식행동의 관계를 살펴보고, 사회지향성과 사회문화적 압력이 폭식행동에 영향을 미치는 과정에서 인지왜곡의 매개효과를 검증하고자 하였다. 이를 위해 청소년 여학생 551명이 연구에 참여하였으며, 이 중 중학생은 206명, 고등학생은 345명이었다. 연구의 주요 변인들을 측정하기 위해 성격양식 질문지(PSI-Ⅱ), 삼자영향 척도(TIS-R), Mizes의 인지왜곡 척도(MACS), 신경성 폭식증 검사 개정판(BULIT-R) 질문지를 사용하였다. 연구 결과는 다음과 같다. 첫째, 신경성 폭식증 검사 점수를 기준으로 청소년 여학생들을 폭식경향 집단과 정상집단으로 구분하여 비교한 결과, 폭식경향 집단에서 신체질량지수(BMI), 사회지향성, 사회문화적 압력, 인지왜곡의 수준이 유의하게 높게 나타났다. 둘째, 주요 변인들 간의 상관관계 분석결과, 사회지향성, 사회문화적 압력, 인지왜곡, 폭식행동 간 관련성이 유의하였다. 셋째, 매개분석 결과, 사회지향성, 사회문화적 압력, 인지왜곡이 폭식행동에 유의한 영향을 미친다는 것이 확인되었으며, 사회지향성과 사회문화적 압력이 인지왜곡에 의해 완전 매개되는 모형이 자료에 잘 부합되는 것으로 나타났다. 즉, 사회지향성과 사회문화적 압력이 섭식관련 인지왜곡을 매개로 하여 폭식행동에 간접적으로 영향을 미친다는 것이 확인되었다. 이러한 결과를 중심으로 본 연구의 임상적 함의와 제한점 및 향후 연구에 대한 시사점을 논의하였다.

비처리 연골과 냉동건조 연골의 변형에 대한 비교 연구

최해천,윤근철,강정훈,오두영 大韓成形外科學會 1998 Archives of Plastic Surgery Vol.25 No.6

Human untreated costal cartilage was compared with lyophilized human costal cartilage which was treated with defatting solution for 48 hours and freeze drying for 72 hours (-70℃, 10??bar) on the tendency of distortion. All cartilages, which were taken from six cadavers, were carved 5×5×30mm in size on principle of the balanced cross section. Their distortions were evaluated by two methods at intervals of one week, one month, three months, six months after experiment. At first, the degree of distortion was grossly graded with four steps: grade O; no distortion / grade Ⅰ; minimal distortion / grade Ⅱ; moderate distortion / grade Ⅲ; severe distortion. Second method is measurement and quantification of distortion in the horizontal and vertical plane of cartilage. Untreated cartilage is shown to be an unsatisfactory material, with only three(12%) of the 25 cartilages being cosmetically acceptable(grade 0 and 1) after 6 months. In lyophilized cartilage, 18(94%) of the 19 cartilages were cosmetically acceptable(grade 0 and 1) at 6 months. This figure is highly significant(p<0.01). In another method, distortion in the horizontal(h) and vertical (v) planes of cartilage were measured, and mean values of ???? were calculated. In untreated group, the mean values of ???? were 0.82 at 1 week, 0.91 at 1 month, 1.13 at 3 months, and 1.31 at 6 months. In lyophilized group, the mean values were 0.27 at 1 week, 0.29 at 1 month, 0.40 at 3 months and 0.47 at 6 months. All values were statistically significant(p<0.01).

어안렌즈왜곡 및 원근왜곡의 보정

송광열(Gwang Yul Song),윤팔주(PalJoo Yoon),이준웅(Joon Woong Lee) Korean Society for Precision Engineering 2006 한국정밀공학회지 Vol.23 No.10

This paper considers the lens distortions such as a fisheye distortion and a perspective distortion. While a fisheye lens has a wide field-of-view, it causes a large distortion to the images. Regardless of a fisheye lens or a rectilinear lens, a lens generates perspective distortion in a vertical direction when the lens views in an upward direction or downward direction. These distortions deform images differently from human visual functions. Therefore, this paper presents a method to correct the distortions, and whereby, the research in this paper enlarges choices of images to image processing algorithm that may select the distorted images and the corrected images depending on applications. An infinite polynomial model is employed in the fisheye radial distortion correction, and the vertical perspective distortion correction is done by using a vanishing point. The methods introduced in this paper are implemented on the images captured by a rear-view camera installed on a vehicle and showed their robustness of the correction.