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.

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.

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

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

글로벌 경쟁사회와 미래의 불확실한 상황에서 국가의 생존과 국익 확보를 위한 국가안보정책은 자원의 분배와 구성에 관한 국가정책임에도 불구하고 정보 부족과 정보의 정치화 둥 다양한 요인으로 인한 정보왜곡 문제가 논란의 대상이 되고 있다. 그러나 정보업무의 특성으로 인해 국가안보 정책결정과정에서 정보왜곡의 발생요인에 대한 체계적인 연구는 매우 부족한 것이 현실이다. 따라서 본 연구에서는 우선 여러 학문분야에서 이루어진 정보왜곡의 발생요인에 대한 국내외 연구 자료들을 체계적으로 조감해 보는 한편, 선행연구에서 추출된 정보왜곡 요인변수를 독립변수와 매개변수 및 조절변수로 구분하고 그 하위변수 모두를 성별ㆍ연령ㆍ취급연한ㆍ담당업무 둥 개인적 특성에 따른 전문가 대상 설문조사 결과, 정보왜곡은 직접적으로 정보실패의 요인 될 수 있으며, 정책결정자로 하여금 잘못된 정책결정을 유도하여 국가의 생존과 번영을 위해 돌이킬 수 없는 국가안보정책의 실패를 야기할 수 있다는 점을 인식하게 되었다. 정보왜곡은 상당부분은 정보생산자인 정보기관의 수집ㆍ분석ㆍ배포 과정에서 비롯된다. 하지만 2003년 미국의 이라크 WMD에 관한 정보판단의 왜곡사용 사례에서와 같이 정보기관의 실책 이상으로 최고정책결정자인 대통령과 문지기인 핵심관료들이 정치적 욕구에 의해 정보를 조작했을 가능성이 큰 것으로 평가되었다. 이런 맥락에서 국민의 생명과 국익을 보호하기 위한 국가안보 정책결정 과정에서의 정보왜곡을 극복하기 위해서 정보생산자와 정보사용자 모두는 객관적인 시각, 전문가적 책무성, 정직성, 윤리성을 제고하기 위한 노력이 필요함이 강조된다. 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).

카메라 교정 및 측정부 회전을 이용한 가상현실 기기의 전역 왜곡 측정법

양동근,강필성,김영식 한국광학회 2019 한국광학회지 Vol.30 No.6

A compact virtual-reality (VR) device with wider field of view provides users with a more realistic experience and comfortable fit, but VR lens distortion is inevitable, and the amount of distortion must be measured for correction. In this paper, we propose two different full-field distortion-measurement methods, considering the characteristics of the VR device. The first is the distortion-measurement method using multiple images based on camera calibration, which is a well-known technique for the correction of camera-lens distortion. The other is the distortion-measurement method by measuring lens distortion at multiple measurement points by rotating a camera. Our proposed methods are verified by measuring the lens distortion of Google Cardboard, as a representative sample of a commercial VR device, and comparing our measurement results to a simulation using the nominal values.

A Simple Switched Capacitor Compensator to Minimize Zero-Crossing Distortion in Single-Phase PFC Converters

Yan Zhang,Jinjun Liu,Chaoyi Zhang 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper explorers techniques for minimizing zero-crossing distortion in single-phase PFC converters from the angle of topologies. Zero-crossing distortions of typical single-phase PFC topologies are compared in theory to reveal that cusp distortion is predominant responsible for zero-crossing distortion. PWM rectifier with the capability of bi-directional current can minimum and eliminate zerocrossing distortion even though there is phase displacement in current loop at the cost of increasing switching loss and larger boost inductor. Then, a simple switched capacitor compensation scheme with low voltage rating switching devices and low switching frequency is presented to minimum zero-crossing distortion. Furthermore, the proposed switched capacitor circuit can be added to existing single-phase PFC converters without modification of original topologies and controllers, hence it is economically feasible. Numerical simulations are given to validate the theoretical analysis and effectiveness of the proposed scheme. With switched capacitor compensator, single-phase PFC converters demonstrate good input performance.

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.