• 제어로봇시스템학회논문지
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• 제15권10호
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• pp.1047-1055
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• 2009

Since nuclear and chemical materials could damage people and disturb battlefield missions in a wide region, nuclear/chemical reconnaissance systems utilizing multiple mobile robots are highly desirable for rapid and safe reconnaissance. In this paper, we design a nuclear/chemical reconnaissance system including mobile robots. Also we propose time-efficient trajectory planning algorithms using grid coverage and contour finding methods for reconnaissance operation. For grid coverage, we performed in analysis on time consumption for various trajectory patterns generated by straight lines and arcs. We proposed BCF (Bounded Contour Finding) and BCFEP (Bounded Contour Finding with Ellipse Prediction) algorithms for contour finding. With these grid coverage and contour finding algorithms, we suggest trajectory planning algorithms for single, two or four mobile robots. Various simulations reveal that the proposed algorithms improve time-efficiency in nuclear/chemical reconnaissance missions in the given area. Also we conduct basic experiments using a commercial mobile robot and verify the time efficiency of the proposed contour finding algorithms.

• 대한전기학회논문지
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• 제38권8호
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• pp.658-666
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• 1989

In this paper, an efficient algorithm for estimation volume and surface area and a reconstruction algorithm for 3-dimensional graphics are presented.In order to improve computing efficiency, the graph theory is utilized and the algorithm to obtain proper contour points is developed by considering several tolerances. Search for the contour points is limited by the change of curvature of cross sectional contour to provide efficiency in searching the minimum cost path. In computer simulation of these algorithms, the results show that, for the tolerance values of 1.001 and 1.002, the execution time reduced to 66%-80% and the error for the measured value is less than 3%. The reconstructed 3-dimensional images from the cross sections can be analyzed in many directions using the graphic scheme.

• 한국CDE학회논문집
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• 제3권1호
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• pp.15-21
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• 1998

Several adaptive and direct slicing methods have been developed to make the slice data for RP parts with better accuracy and speed. This research deals with a new adaptive slicing algorithm that shows drastic improvement in computing time for calculating the slices of a part. First, it uses less number of sampling points fur each slice in determining the thickness of the next slice. Secondly, the idea of contour map is utilized to determine the optimal sampling point on each slice. Thirdly, the calculation efficiency is further improved by introducing vertical character lines of the given part. The results in terms of accuracy and speed are compared with the existing methods.

• 대한전자공학회논문지
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• 제25권12호
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• pp.1677-1685
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• 1988

In this paper, a new contour coding algorithm is investigated for use in region based image coding. Generally the contour data may be encoded by its chain codes or chain difference codes. But the data compression efficiency is low because of heavy burden for initial absolute coordinates of each chain. To alleviate this problem, the depth first search in graph traversal algorithm, is applied to the chain difference coding method. The proposed coding scheme is shown to be very efficient for contour images obtained by split-merge segmentation. Finally, we can reuce data about 60% in comparison with modified chain difference coding.

• 한국정밀공학회지
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• 제21권6호
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• pp.160-166
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• 2004

In this study, a new algorithm, named as Contour Offset Algorithm(COA) is developed to fabricate precise features or patterns in the range of several micrometers by nano replication printing(nRP) process. In the nRP process, a femto-second laser is scanned on a photosensitive monomer resin in order to induce polymerization of the liquid monomer according to a voxel matrix which is transformed from the bitmap format file. After polymerization, a droplet of ethanol is dropped to remove the unnecessary remaining liquid resin and then only the polymerized figures with nano-scaled precision are remaining on the glass plate. To obtain more precise replicated features, the contour lines in voxel matrix should be modified considering a voxel size. In this study, the efficiency of the proposed method is shown through two examples in view of accuracy.

• 방송공학회논문지
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• 제1권1호
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• pp.35-43
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• 1996

본 논문에서는 복호화시 정확한 복원이 가능하며 윤곽 상태에 따라 효율적으로 부호화하는 여섯 방향 윤곽부호화 기법을 제안하였다. 먼저 방향벡터의 확률적 분포가 수평 수직 진행 방향과 대각선 진행 방향에서 서로 다르다는 사실에 근거하여 현재의 진행 방향을 두 상태로 나누고, 각 상태별로 다른 코드를 이용하여 부호화하였다. 그리고 부호화 효율을 더욱 높이기 위해 윤곽 상태를 현재 방향벡터와 이진 진행 방향벡터에 따라 다섯 가지로 구분하여 부호화하였다. 또한, 단말 코드워드를 제거함으로써 전체 코드워드 발생 횟수를 줄였다. 실험을 통하여 단말 코드를 제거하고 두 상태 및 다섯 상태로 나누었을 때 전체 엔트로피는 실영상에 대해서는 각각 12%, 14%정도, 합성영상에 대해서는 각각 10%, 26%정도로 크게 감소함을 확인할 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권11호
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• pp.5605-5623
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• 2016

We propose a face recognition method that utilizes the LCP face descriptor. The proposed method applies a LoG mask to extract a face contour response, and employs the LCP algorithm to produce a binary pattern representation that ensures high recognition performance even under the changes in illumination, noise, and aging. The proposed LCP algorithm produces excellent noise reduction and efficiency in removing unnecessary information from the face by extracting a face contour response using the LoG mask, whose behavior is similar to the human eye. Majority of reported algorithms search for face contour response information. On the other hand, our proposed LCP algorithm produces results expressing major facial information by applying the threshold to the search area with only 8 bits. However, the LCP algorithm produces results that express major facial information with only 8-bits by applying a threshold value to the search area. Therefore, compared to previous approaches, the LCP algorithm maintains a consistent accuracy under varying circumstances, and produces a high face recognition rate with a relatively small feature vector. The test results indicate that the LCP algorithm produces a higher facial recognition rate than the rate of human visual's recognition capability, and outperforms the existing methods.

• 전자공학회논문지B
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• 제31B권1호
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• pp.72-80
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• 1994

In this paper, a new variable block-size transform coding algorithm using information of segmentation is proposed. In general variable block-size transform coding algorithms, the information which is used to form variable blocks is thrown away, but in the proposed algorithm, the information of segmentation which is composed of texture and contour information is maintained for efficient coding. That is, the number of blocks can be reduced by contour information, a DC component of block can be predicted by texture information, and the region compensation, which reduces mean difference between regions, using texture and contour information can diminish the magnitude of AC components. The result is that the proposed algorithm has improved highly the coding efficiency of DC and AC components.

• 한국항행학회논문지
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• 제27권2호
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• pp.214-220
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• 2023

모터와 ESC (Electronic Speed Control)는 높은 효율을 유지할 수 있는 회전 속도 및 토크의 범위가 존재하기 때문에, 효율적인 시스템 설계를 위해서는 이 범위를 파악하는 것이 중요하다. 본 논문에서는 먼저 측정 장비 대한 정확성을 프로펠러 측정 데이터와 비교 분석하여 검증하였다. 다음으로, 넓은 회전 속도 범위에서의 정적 측정을 통해 각 프로펠러에 대한 통합 효율을 측정하고, 이를 다수의 프로펠러에서 반복하여 얻은 데이터를 이용하여 효율 등치선도를 도출하였다. 측정된 모터-ESC 통합 효율은 단순한 모터 모델로 도출한 모터 자체의 효율과 비교할 때 상당한 차이가 있음을 확인하였고, 또한 동일한 모터라도 ESC에 따라 달라지는 효율의 차이를 분석하였다. 본 연구를 통해 도출한 모터-ESC 통합 효율 등치선도는 추진 효율이 중요한 항공기의 전기 추진 시스템을 설계하고 최적화하는 데에 유용하게 사용될 것으로 예상된다.

• 대한의용생체공학회:의공학회지
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• 제28권4호
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• pp.549-555
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• 2007

In order to study cortical properties in human, it is necessary to obtain an accurate and explicit representation of the cortical surface in individual subjects. Among many approaches, surface-based method that reconstructs a 3-D model from contour lines on cross-section images is widely used. In general, however, medical brain imaging has some problems such as the complexity of the images, non-linear gain artifacts and so on. Due these limitations, therefore, extracting anatomical structures from imaging data is very a complicated and time-consuming task. In this paper, we present an improved method for extracting contour lines of cortical surface from magnetic resonance images that simplifies procedures of a conventional method. The conventional method obtains contour lines through thinning and chain code process. On the other hand, the proposed method can extract contour lines from comparison between boundary data and labeling image without supplementary processes. The usefulness of the proposed method has been verified using brain image.