• Journal of Broadcast Engineering
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• v.1 no.2
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• pp.176-187
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• 1996

This paper deals with the accurate estimation of 3- D pose (position and orientation) of a moving object with reference to the world frame (or robot base frame), based on a sequence of stereo images taken by cameras mounted on the end - effector of a robot manipulator. This work is an extension of the previous work[1]. Emphasis is given to the 3-D pose estimation relative to the world (or robot base) frame under the presence of not only the measurement noise in 2 - D images[ 1] but also the camera position errors due to the random noise involved in joint angles of a robot manipulator. To this end, a new set of discrete linear Kalman filter equations is derived, based on the following: 1) the orientation error of the object frame due to measurement noise in 2 - D images is modeled with reference to the camera frame by analyzing the noise propagation through 3- D reconstruction; 2) an extended Jacobian matrix is formulated by combining the result of 1) and the orientation error of the end-effector frame due to joint angle errors through robot differential kinematics; and 3) the rotational motion of an object, which is nonlinear in nature, is linearized based on quaternions. Motion parameters are computed from the estimated quaternions based on the iterated least-squares method. Simulation results show the significant reduction of estimation errors and also demonstrate an accurate convergence of the actual motion parameters to the true values.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.4
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• pp.297-305
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• 2014

In this study, we installed the Automatic Identification System (AIS) receiver on the Ieodo Ocean Research Station (IORS) from November 21 to 30, 2013 in order to monitor marine traffic and fishery activity in the jurisdictional sea area. The collected AIS raw data consist of static data report (MMSI, IMO NO., Call Sign, Ship Name, etc.) and position information report (position, speed, course, etc.), and the developed program was applied to classify ships according to ship flag and type information. The nationalities are released from the first three-digit numbers (MID) of MMSI, but in general most of small ships do not send an exact ship flag through Class B type AIS, a simplified and low-power equipment. From AIS data with flag information, ships under the flag of China had the highest frequency and the second was Korean flag, while in ship type cargo and fishing vessels were dominant in sequence. As for the ships without flag information, we compared the tracks with others in order to estimate ship flags. It can be said that fleets of ships with Chinese frequently appear sail together for fisheries over the waters, because the unknown ships followed a similar moving pattern with Chinese fishing vessels.

• The KIPS Transactions:PartB
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• v.11B no.6
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• pp.653-660
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• 2004

Object-oriented analysis-synthesis coding (OOASC) subdivides each image of a sequence into a number of moving objects and estimates and compensates the motion of each object. It employs a motion parameter technique for estimating motion information of each object. The motion parameter technique employing gradient operators requires a high computational load. The main objective of this paper is to present efficient motion parameter estimation techniques using the hierarchical structure in object-oriented analysis-synthesis coding. In order to achieve this goal, this paper proposes two algorithms : hybrid motion parameter estimation method (HMPEM) and adaptive motion parameter estimation method (AMPEM) using the hierarchical structure. HMPEM uses the proposed hierarchical structure, in which six or eight motion parameters are estimated by a parameter verification process in a low-resolution image, whose size is equal to one fourth of that of an original image. AMPEM uses the same hierarchical structure with the motion detection criterion that measures the amount of motion based on the temporal co-occurrence matrices for adaptive estimation of the motion parameters. This method is fast and easily implemented using parallel processing techniques. Theoretical analysis and computer simulation show that the peak signal to noise ratio (PSNR) of the image reconstructed by the proposed method lies between those of images reconstructed by the conventional 6- and 8-parameter estimation methods with a greatly reduced computational load by a factor of about four.

• Korean journal of applied entomology
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• v.53 no.2
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• pp.177-183
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• 2014

The ussur brown katydid, Paratlanticus ussuriensis (Orthoptera: Tettigoniidae), causes substantial damage in orchard areas in South Korea. Daily rhythm and mating behaviors were investigated in last instar nymphs, immature adults and mature adults of P. ussuriensis. The daily rhythm was repeated upon resting, moving, and feeding. The daily rhythm of the movement behavior similar in both last instar nymphs and immature adults. Last instar nymphs becoming active at 10:06 and ceasing activity at 21:12 in average. Immature adults becoming active at 11:30 and ceasing activity at 20:08 in average of totally 10 individuals. However, mature adults showed a different active time of 15:30. Generally, behavior was affected by the conditions of their environment, especially temperature. Mature adults activated later than nymphs and immature adults. Mature adults display mating behavior at a particular time of day (approximately 20:00). P. ussuriensis showed a mating behavioral sequence which was similar to related species in completely retaining the spermatophylax. Females took 270 min to 360 min to completely retain the spermatophylax. The daily rhythm of P. ussuriensis, indicating its occurrence and ecology, could be useful as basic data for managing field populations of P. ussuriensis.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.8
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• pp.132-139
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• 2015

Visual SLAM(Simultaneous Localization And Mapping) has been used widely to estimate a mobile robot's location. Visual SLAM estimates relative motions with static visual features over image sequence. Because visual SLAM methods assume generally static features in the environment, we cannot obtain precise results in dynamic situation including many moving objects: cars and human beings. This paper presents a stereo vision based SLAM method in dynamic environment. First, we extract disparity map with stereo vision and compute optical flow. We then compute disparity change that is the estimated flow field between stereo views. After examining the disparity change value, we detect ROIs(Region Of Interest) in disparity space to determine dynamic scene objects. In indoor environment, many structural planes like walls may be determined as false dynamic elements. To solve this problem, we segment the scene into planar structure. More specifically, disparity values by the stereo vision are projected to X-Z plane and we employ Hough transform to determine planes. In final step, we remove ROIs nearby the walls and discriminate static scene elements in indoor environment. The experimental results show that the proposed method can obtain stable performance in dynamic environment.

• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1597-1609
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• 2004

A lot of lipreading system has been proposed to compensate the rate of speech recognition dropped in a noisy environment. Previous lipreading systems work on some specific conditions such as artificial lighting and predefined background color. In this paper, we propose a real-time lipreading system which allows the motion of a speaker and relaxes the restriction on the condition for color and lighting. The proposed system extracts face and lip region from input video sequence captured with a common PC camera and essential visual information in real-time. It recognizes utterance words by using the visual information in real-time. It uses the hue histogram model to extract face and lip region. It uses mean shift algorithm to track the face of a moving speaker. It uses PCA(Principal Component Analysis) to extract the visual information for learning and testing. Also, it uses HMM(Hidden Markov Model) as a recognition algorithm. The experimental results show that our system could get the recognition rate of 90% in case of speaker dependent lipreading and increase the rate of speech recognition up to 40～85% according to the noise level when it is combined with audio speech recognition.

• Korean Journal of Optics and Photonics
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• v.15 no.5
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• pp.435-442
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• 2004

We obtained precise linear transverse displacements from the results of signal processing on moire fringes measured by the superposition of a fixed self-imaging elongated circular(EC) grating and a moved EC grating. The linear displacement less than one pitch of the moving EC grating was calculated from the position of a bright moire fringe generated on the linear grating part of the EC gratings. The moire signals were high-frequency-filtered, smoothed, curve-fitted, and first-differentiated moire signals in sequence. Also the linear displacement created by movement by the unit of integer times of a pitch was readily measured by the count of the even number of zero-crossing points corresponding to bright moire fringes obtained by the above same processing without curve fitting. Then we can measure linear transverse displacements with the accuracy of better than 3 %, which are more accurate values than those by the traditional visual method within the displacement of 80 ${\mu}{\textrm}{m}$.

• Journal of the Korea Computer Graphics Society
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• v.9 no.3
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• pp.23-29
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• 2003

There is the temporal correlation of the video sequence between the motion vector of current block and the motion vector of the previous block. If we can obtain useful and enough information from the motion vector of the same coordinate block of the previous frame, the total number of search points used to find the motion vector of the current block may be reduced significantly. In this paper, we propose the block-matching motion estimation using an adaptive initial search point by the predicted motion information from the same block of the previous frame. And the first search point of the proposed algorithm is moved an initial point on the location of being possibility and the searching process after moving the first search point is processed according to the fast search pattern. Simulation results show that PSNR(Peak-to-Signal Noise Ratio) values are improved UP to the 1.05dB as depend on the image sequences and improved about 0.33~0.37dB on an average. Search times are reduced about 29~97% than the other fast search algorithms. Simulation results also show that the performance of the proposed scheme gives better subjective picture quality than the other fast search algorithms and is closer to that of the FS(Full Search) algorithm.

• Korean Journal of Environment and Ecology
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• v.20 no.3
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• pp.289-298
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• 2006

The purpose of this study was to investigate salt marsh flora and vegetation in the mouth of Mankyeong river estuary area where has a project for Sea Man Geum Reclaimed Land so that we can foster a foundation on restoration of an ecological habitat, development of applicable plants and establishment of a conservation policy after developing the reclaimed land for salt marsh vegetation which has great ecological value. As a result of this research, there are 10 families 25 genera 29 species and 3 varieties of vascular plants in the Mankyong-river estuary area. These are 0.76% among 4,191 of Korean vascular plants. There are also 5 families 6 genera 6 species and 1 varietiy of the naturalized plants which are 7 taxa in total and 3.85% of indicators of naturalized plants. Firstly, a district of low tide marsh has below 5% of vegetation coverage of Suaeda japonica and the vegetation cover was increasing rapidly while moving to a place of high tide marsh which is in the direction to a bank. In general, a range of from low tide marsh to high tide marsh is distributed with sequence of Suaeda japonica$\rightarrow$Suaeda maritima$\rightarrow$Suaeda japonica$\rightarrow$Aster tripolium$\rightarrow$Artemisia scoparia$\rightarrow$Carex scabrifolia$\rightarrow$Zoysia sinica$\rightarrow$Phragmites australis$\rightarrow$Phacelurus latifolius. Suaeda japonica has the highest dominance among the species composition and Aster tripolium, Phragmites australis, Artemisia scoparia, Carex scabrifolia and Phacelurus latifolius are distributed as zonation or patch. By the Z-M method eleven plant communities were recognized; Suaeda japonica, Suaeda japonica-Suaeda maritima, Suaeda maritima, Suaeda japonica-Aster tripolium, Aster tripolium, Phragmites australis, Carex scabrifolia, Phacelurus latifolius, Artemisia scoparia-Aster tripolium, Paspalum distichum var. indutum and Aster tripolium-Artemisia scoparia community. The actual vegetation map was constructed of the grounds of the communities classified and other data.

• Journal of the Korean Institute of Landscape Architecture
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• v.16 no.3
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• pp.21-37
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• 1989

Environmental design pattern of the nine Small Urban Spaces at C.B.D. in City of Seoul are surveyed and analyzed for user's satisfaction and behavior under the environmental design evaluation by using Christopher Alexander's Pattern Language. Small Urban Spaces as a part of streetscape are formed by physical factors as well as visual environment and interacting user's behavior. Therefore, user's satisfaction and behavior at the nine Urban Small Spaces were investigated under the further search for some possibilities of application of those Pattern Languages. A pattern language has a structure of a network. It is used in sequence, going through the patterns, moving always from large patterns to smaller, always from the ones which create comes simply from the observation that most of the wonderful places of the city were not blade by architects but by the people. It defines the limited number of arrangements of spaces that make sense in any given culture. And it actually gives us the power to generate these coherent arrangement of space. As a results, 'Plaza', 'Seats'and 'Aecessibility' related design Patterns are highly evaluated by Pattern Frequency, Pattern Interaction and their Composition ranks, thus reconfirm Whyte's Praise of urban Small Spaces in our inner city design environments. According to the multiple regression analysis of user's evaluation, the environmental functions related to the satisfaction were 'Plaza', 'Accessibility' and 'Paving'. According to the free response, user's prefer such visually pleasing environmental design object as 'Waterscape' and 'Setting'. In addition to, the basic needs in Urban Small Spaces are amenity facilities as bench, drinking water and shade for rest.