A Vertical and Floor Line-based Monocular SLAM System for Corridor Environments

장국현,서일홍 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.3

In this paper, we propose a vertical and floor line-based monocular simultaneous localization and mapping (SLAM) system which utilizes vertical lines, floor lines, and vanishing points as sensory input to perform robust SLAM in corridor environments. By combining three map feature types, our design can help a robot to perform accurate pose estimation, repeatable loop closure, and to construct a more expressive environmental map. As a primitive element of a geometric structure, a line segment has one additional dimension compared to a point feature, thereby allowing the use of line segments to easily represent a geometric structure using a smaller number of features. This system presents map features on a 2D ground space: the vertical line as a projection point, the floor line as the original line, and the vanishing point as a directional vector. Although the vertical line, floor line, and vanishing point use different parameterization and initialization methods, their measurement models are integrated into a unified extended Kalman filter (EKF) framework. Experimental results show that our system can be deployed in a structured indoor environment as a suitable SLAM solution.

직선기반 SLAM에서의 루프결합

장국현,서일홍 한국로봇학회 2012 로봇학회 논문지 Vol.7 No.2

The loop closure problem is one of the most challenging issues in the vision-based simultaneous localization and mapping community. It requires the robot to recognize a previously visited place from current camera measurements. While the loop closure often relies on visual bag-of-words based on point features in the previous works, however, in this paper we propose a line-based method to solve the loop closure in the corridor environments. We used both the floor line and the anchored vanishing point as the loop closing feature, and a two-step loop closure algorithm was devised to detect a known place and perform the global pose correction. We propose an anchored vanishing point as a novel loop closure feature, as it includes position information and represents the vanishing points in bi-direction. In our system, the accumulated heading error is reduced using an observation of a previously registered anchored vanishing points firstly, and the observation of known floor lines allows for further pose correction. Experimental results show that our method is very efficient in a structured indoor environment as a suitable loop closure solution.

Novel Calibration Method for the Multi-Camera Measurement System

Xinlei Wang 한국광학회 2014 Current Optics and Photonics Vol.18 No.6

In a multi-camera measurement system, the determination of the external parameters is one of the vital tasks, referred to as the calibration of the system. In this paper, a new geometrical calibration method, which is based on the theory of the vanishing line, is proposed. Using a planar target with three equally spaced parallel lines, the normal vector of the target plane can be confirmed easily in every camera coordinate system of the measurement system. By moving the target into more than two different positions, the rotation matrix can be determined from related theory, i.e., the expression of the same vector in different coordinate systems. Moreover, the translation matrix can be derived from the known distance between the adjacent parallel lines. In this paper, the main factors effecting the calibration are analyzed. Simulations show that the proposed method achieves robustness and accuracy. Experimental results show that the calibration can reach 1.25 mm with the range about 0.5m. Furthermore, this calibration method also can be used for auto-calibration of the multi-camera measurement system as the feature of parallels exists widely.

Vanishing Points Detection in Indoor Scene Using Line Segment Classification

Chaoqing Ma(마조청),Oubong Gwun(권오봉) 한국콘텐츠학회 2013 한국콘텐츠학회논문지 Vol.13 No.8

본 논문에서는 선분분류를 이용하여 실내영상의 소실점을 검출하는 방법을 제안한다. 실내영상을 효율적으로 검출하기 위하여 2 단계로 소실점을 추출한다. 1 단계에서는 이미지가 1 점 투시인지 2 점 투시인지 판별한다. 만일 이미지가 2 점 투시이면, 선분분류를 위하여 검출된 소실점을 지나는 수평선을 구한다. 2단계에서는 선분분류를 이용하여 2 개의 소실점을 정확히 검출한다. 또 본 논문에서는 인공영상과 이미지 DB를 이용하여 제안한 방법을 평가하였다. 노이즈를 첨가한 인공 영상에 대해서는 노이즈가 60%를 차지할 때까지 검출한 소실점과 실제 소실점과의 차이가 16 픽셀 이하였다. A. Quattoni 와 A. Torralba가 제안한 이미지 DB를 이용한 평가에서는 87% 이상의 이미지에 대하여 소실점을 검출하였다. This paper proposes a method to detect vanishing points of an indoor scene using line segment classification. Two-stage vanishing points detection is carried out to detect vanishing point in indoor scene efficiently. In the first stage, the method examines whether the image composition is a one-point perspective projection or a two-point one. If it is a two-point perspective projection, a horizontal line through the detected vanishing point is found for line segment classification. In the second stage, the method detects two vanishing points exactly using line segment classification. The method is evaluated by synthetic images and an image DB. In the synthetic image which some noise is added in, vanishing point detection error is under 16 pixels until the percent of the noise to the image becomes 60%. Vanishing points detection ratio by A.Quattoni and A.Torralbas image DB is over 87%.

자율주행 로봇의 외부환경 이해를 위한 기하학적인 빌딩 분석

김대년(Dae-Nyeon Kim),찐황헌(Hoang-Hon Trinh),조강현(Kang-Hyun Jo) 제어로봇시스템학회 2010 제어·로봇·시스템학회 논문지 Vol.16 No.3

This paper describes an approach to analyze geometrical information of building images for understanding outdoor environment of autonomous navigation robot. Line segments and color information are used to classify a building with the other objects such as sky, trees, and roads. The line segments and their two neighboring regions are extracted from detected edges in image. The model of line segment (MLS) consists of color information of neighbor regions. This model rules out the line segments of non-building face. A building face converges into dominant vanishing points (DVPs) which include one vertical point and one of five horizontal points in maximum. The intersection of vertical and horizontal lines creates a facet of building. The geometrical characteristics such as the center coordinates, area, aspect ratio and aligned coexistence are used for extracting the windows in the building facet. In experiments, 150 building faces and 1607 windows were detected from the database of outdoor environment. We found that this result shows 94.46% detection rate. These experimental images were all taken in Ulsan metropolitan city in Korea under difference of viewpoints, daytime, camera system and weather condition.

Fast and Accurate Self-calibration Using Vanishing Point Detection in Manmade Environments

Sang Jun Lee,Sung-Soo Hwang 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.10

Interests of auto-calibration have been increased in several camera systems. This paper presents a novel self-calibration method using a fast and accurate vanishing point detection algorithm that works in manmade environments. The proposed algorithm estimates focal length assuming that the principal point is the center of an image to satisfy the orthogonality of three vanishing points. By using the proposed vanishing point detection algorithm and minimization of the proposed objective function, the proposed system detects accurate vanishing points with focal length outperforming other methods. The proposed vanishing point detection algorithm detects vanishing points by using J-linkage based method that is more delicate by fragmentation and re-merging strategies. The proposed objective function finally detects vanishing points that meet orthogonality among estimated hypotheses for vanishing points by checking several geometric relationships. We believe that the proposed method can be used for automatic camera calibration, localization of a camera in an autonomous navigation system, and three-dimensional reconstruction of a single-view image.

최명익의 <心紋>에 나타난 시선의 함의

류동일 한국현대소설학회 2012 현대소설연구 Vol.- No.50

This paper aims to clarify implications of sight of a narrator in Choi Myung-Ik' <Simmoon>(心紋). Apart from Choi Myung-Ik's other works which had sought to discover position on a intellectual by contrast with men of modern life, <Simmoon> was specific that it revealed narrator's observation to Hyun Hyuk(현혁), which was distinctive character. In this way, what grasps meaning of <Simmoon>is important. A discipline of the modern civilized world, a speed divided world in accordance with accommodated or unaccommodated to itself. In <Simmoon>, Mr. Lee(이군) accommodated to division of speed, so that his life was analyzed into character that drew the rigid line of segmentarity that Deleuze and Guattari defined as a mode which depended on settled criteria by world's majority. In contrast to with Mr. Lee, Hyun Hyuk willingly rejected adjustment rejected adjustment in real world and destroyed himself through opium. This life mode of Hyun Hyuk could be defined as the line of flight of death which Deleuze and Guattari defined, for life mode of him revealed not becoming but rather vanishing himself and Yeo-Yok(여옥). A narrator in <Simmoon>, Myeong-Il(명일) drew on the rigid line of segmentarity, as he acted to gain new and stable job through dependence on Mr. Lee in the early stage of the novel. Through meeting on Yeo-Yok and Hyun Hyuk, however, Myeong-Il begun to gut out of the adjusted attitude to discipline of world. Through this way, he drew on the line of supple segmentation, which Deleuze and Guattari defined as being between the rigid line of segmentarity and the line of flight because of discovery to minute difference. Through conclusion at undetermined state to direction determination, <Simmoon> showed careful attitude to direction determination. It could be relieved of danger of microfascism, danger of recurrence of the Eastern Mind that the line of flight of death which manifested denial against Wastern modern in the turning point might fall into. Choi Myung-Ik' <Simmoon> acquired that significance. 이 글은 최명익의 <心紋>에 나타난 화자의 시선의 의미를 밝히는 것을목적으로 한다. 근대를 살아가는 생활인과의 대비 속에서 지식인의 위치를모색한 최명익의 여타 작품들과 달리, <心紋>에는 현혁이라는 독특한 인물이 등장한다. 이런 점에서 <心紋>의 의미를 파악하는 것은 중요하다. 근대적 문명 세계의 질서를 뜻하는 속도는 자신에게 적응하느냐 적응하지 못하느냐에 따라 세계를 구획한다. 이군은 이 속도가 제공하는 구획에순응하고 있다는 점에서, 들뢰즈와 가타리가 세계의 다수성에 의해 규정한 삶의 양식을 그대로 따르는 방식으로 나타낸 견고한 분할선을 그리는자로 해석될 수 있다. 이와 달리 현혁은 현실에 적응하기를 의도적으로 거부하고 아편을 통해 스스로를 파괴한다. 이러한 현혁의 삶의 방식은 들뢰즈와 가타리가 내세운 죽음의 도주선을 그린 것으로 해석될 수 있는데, 이는 그의 삶이 생성보다는 여옥과 자신을 소멸시키는 방식으로 나타나기때문이다. 소설 속 화자인 명일은 소설 초반부에는 이군을 통해 새롭고 안정된 직업을 획득하고자 함으로써 견고한 분할선을 그리려는 모습을 보여준다. 그러나 여옥 및 현혁과의 만남을 통해 명일은 세계가 정해 놓은 질서를 따르는 태도에서 벗어나기 시작한다. 이를 통해 명일은 들뢰즈와 가타리가 미세한 차이의 발견을 통해 견고한 분할선과 도주선 사이에 존재하는 것으로규정한 유연한 분할선을 그리게 된다. 이 소설은 방향이 결정되지 않은 상태에서 마무리됨으로써 방향 결정에있어서 신중한 태도를 보여준다. 이러한 태도는 전형기 현실 속에서 서구적 근대를 향한 부정을 내세운 죽음의 도주선이 가져올 수 있는 동양정신으로의 회귀, 즉 미시파시즘의 위험성에서 벗어나게 해 주는 것이기도 하다. 이것이 바로 최명익의 <心紋>이 가진 의의라 하겠다.

최명익의 <심문(心紋)>에 나타난 시선의 함의

유동일(Dong Il Ryu) 한국현대소설학회 2012 현대소설연구 Vol.- No.50

This paper aims to clarify implications of sight of a narrator in Choi Myung-Ik` <Simmoon>(心紋). Apart from Choi Myung-Ik`s other works which had sought to discover position on a intellectual by contrast with men of modern life, <Simmoon> was specific that it revealed narrator`s observation to Hyun Hyuk(현혁), which was distinctive character. In this way, what grasps meaning of <Simmoon> is important. A discipline of the modern civilized world, a speed divided world in accordance with accommodated or unaccommodated to itself. In <Simmoon>, Mr. Lee(이군) accommodated to division of speed, so that his life was analyzed into character that drew the rigid line of segmentarity that Deleuze and Guattari defined as a mode which depended on settled criteria by world`s majority. In contrast to with Mr. Lee, Hyun Hyuk willingly rejected adjustment rejected adjustment in real world and destroyed himself through opium. This life mode of Hyun Hyuk could be defined as the line of flight of death which Deleuze and Guattari defined, for life mode of him revealed not becoming but rather vanishing himself and Yeo-Yok(여옥). A narrator in <Simmoon>, Myeong-Il(명일) drew on the rigid line of segmentarity, as he acted to gain new and stable job through dependence on Mr. Lee in the early stage of the novel. Through meeting on Yeo-Yok and Hyun Hyuk, however, Myeong-Il begun to gut out of the adjusted attitude to discipline of world. Through this way, he drew on the line of supple segmentation, which Deleuze and Guattari defined as being between the rigid line of segmentarity and the line of flight because of discovery to minute difference. Through conclusion at undetermined state to direction determination, <Simmoon> showed careful attitude to direction determination. It could be relieved of danger of microfascism, danger of recurrence of the Eastern Mind that the line of flight of death which manifested denial against Wastern modern in the turning point might fall into. Choi Myung-Ik` <Simmoon> acquired that significance.

Gabor Filter를 이용한 소실선 검출 기반의 깊이 지도 생성 기법

유태훈,이상훈 한국융합학회 2012 한국융합학회논문지 Vol.3 No.1

본 논문에서는 기하학적 단서인 소실선과 텍스처를 이용하여 깊이 지도를 생성하는 방법을 제안한다. 소 실선은 영상 내 존재하는 평행한 직선들에 의해 생성되는 것으로 영상에서 Gabor Filter를 통해 특정 각도의 경계를 추출하고 이를 허프 변환을 통해 직선을 추출하여 소실선을 검출해낸다. 검출된 소실선에 따라 초기 깊이 지도를 생성하고 텍스처 단서인 슈퍼 픽셀을 이용한 상대적 깊이 지도를 결합하여 최종 깊이 지도를 생성한다. 소실선을 이용한 초기 깊이지도와 슈퍼 픽셀을 이용한 상대적 깊이 지도를 결합함으로써 보다 신뢰성 있는 깊이 지도가 생성 되었다.

A Vanishing Point Detection Method Based on the Empirical Weighting of the Lines of Artificial Structures

김항태(Hang-Tae Kim),송원석(Wonseok Song),최혁(Hyuk Choi),김태정(Taejeong Kim) Korean Institute of Information Scientists and Eng 2015 정보과학회논문지 Vol.42 No.5