• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.109-114
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• 2000

A new method for the determination of camera system rotation and translation from in 3-D space using recursive least square method is presented in this paper. With this method, the calculation of the equation is found by a linear algorithm. Where the equation are either given or be obtained by solving five or more point correspondences. Good results can be obtained in the presence if more than the eight point. A main advantage of this new method is that it decouple rotation and translation, and then reduces computation. With respect to error in the solution point number in the input image data, adding one more feature correspondence to required minimum number improves the solution accuracy drastically. However, further increase in the number of feature correspondence improve the solution accuracy only slowly. The algorithm proposed by this paper is used to make camera system rotation and translation easy to recognize even when camera system attached at end effecter of six degrees of freedom industrial robot manipulator are applied industrial field.

• 한국정밀공학회지
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• 제4권2호
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• pp.47-55
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• 1987

Recently, in precision working, precision is in submicron. Therefore, when we measure various finished goods in superfine measurement, because it is relatively difficult to disregard effect of surroundings, these effect of surroundings must be compensated or canceled. In this study, for roundness measurement, three point method is researched which is able to cancel the effect of rotation accuracy of axis and eccenricity of workpiece. It is difference between this three point method and tradi- tional three point method whose measuring apparatus have three movable pickups posit- ioned with angle and between the pickups. As a results, when rotation accuracy of axis is varied from $0.02\mu\textrm{m}$ to $0.05\mu\textrm{m}$ the width of variation of measured roundness is $0.04\mu\textrm{m}$. And, when eccentricity of workpiece is varied from 0 to $4\mu\textrm{m}$, the width of variation of measured roundness is $0.005\mu\textrm{m}$. These error width are disregardable because they are in 10% of measured roundness. Therefore, by this three point method, the effect of rotation accuracy of axis and the effect of eccentricity of workpiece are canceled. And we are able to select the angle between the pickups ($\phi$ and $\tau$) by means of relation between $F_{k}$ and K.

• 대한전자공학회논문지SP
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• 제39권5호
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• pp.535-543
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• 2002

본 논문에서는 모니터 위에 설치된 카메라를 통해 입력된 사용자의 2차원 얼굴 영상을 이용하여, 사용자가 모니터 상에 쳐다보고 있는 응시 위치를 파악하는 방법을 제안한다. 본 논문에서는 사용자의 눈동자 움직임은 고려하지 않고 얼굴의 회전 및 이동만을 고려하였다. 제안하는 방법은 얼굴의 회전에 의한 응시위치와 얼굴의 좌우상하 이동량을 각각 계산하여 이 둘을 결합함으로써 모니터상의 응시위치를 추정하는 것이다. 얼굴 특징점의 기하학적 형태변화를 입력으로 하는 신경망(다층 퍼셉트론)을 이용하여 얼굴의 회전에 의한 응시위치를 구하였으며 영상처리 알고리즘을 이용하여 입력영상으로부터 실시간으로 얼굴의 이동량을 추정하였다. 실험결과 19인치 모니터를 사용하고 사용자가 모니터와의 거리를 50~70cm 정도 유지하며 얼굴의 이동 및 회전을 통하여 모니터를 바라볼 때 약 2.11인치의 응시 위치 추정 오차를 보이는 것으로 나타났다. 처리시간은 Pentium PC(233MHz)환경에서 320${\times}$240 화소 크기의 영상을 사용할 때 약 0.7초가 소요되었다.

• The Journal of Advanced Prosthodontics
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• 제10권6호
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• pp.401-407
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• 2018

PURPOSE. When performing an occlusal procedure, it is recommended that the patient should be sitting straight with the head in a natural position. An inappropriate mandibular position caused by an incorrect occlusal record registration or occlusal adjustment can result in damaged teeth and cause functional disorders in muscles and temporomandibular joints. The purpose of this study was to clarify the influence of horizontal cephalic rotation on mandibular position by investigating the three-dimensional positions of condylar and incisal points. MATERIALS AND METHODS. A three-dimensional jaw movement measurement device with six degrees of freedom (the WinJaw System) was used to measure condylar and incisal points. The subjects were asked to sit straight with the head in a natural position. The subjects were then instructed to rotate their head horizontally $0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$, $40^{\circ}$, $50^{\circ}$and $60^{\circ}$ in the right or left direction. RESULTS. The results indicated that horizontal cephalic rotation made the condyle on the rotating side shift forward, downward, and toward the inside, and the condyle on the counter rotating side shift backward, upward, and toward the outside. Significant differences in deviations were found for angles of rotation higher than $20^{\circ}$. The incisal point shifted in the forward and counterrotating directions, and significant differences were found for angles of rotation higher than $20^{\circ}$. CONCLUSION. The mandibular position was altered by horizontal cephalic rotations of more than $20^{\circ}$. It is essential to consider the possibility of deviation of the mandibular position during occlusal procedures.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
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• pp.901-904
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• 2000

A direct authentication from gray-scale image, instead of the conventional multi-step preprocessing, is proposed using Gabor filter-based features from the gray-scale fingerprint around core point. The core point is located as a reference point for the translation invariant matching. And its principal symmetry axis is detected for the rotation invariant matching from its neighboring region centered at the core point. And then fingerprint is divided into non-overlapping blocks with respect to the core point and features are directly extracted form the blocked gray level fingerprint using Gabor filter. The proposed fingerprint authentication is based on the Euclidean distance between the corresponding Gabor features of the input and the template fingerprints. Experiments are conducted on 300${\times}$300 fingerprints obtained from a CMOS sensor with 500 dpi resolution, and the proposed method could lower the False Reject Rate(FRR) to 18.2% under False Acceptance Rate(FAR) of 0%.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.574-577
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• 2001

This paper presents the comparison of FRI(Foot Rotation Indicator) point and ZMP(Zero Moment Point) in biped robot stability. We showed FRI may be employed as a useful tool in stability analysis in biped robot. Also, we proposed the balancing joint trajectory derived from FRI point equation for stable gait. The numerical calculation routines and walking algorithms for simulation are performed by MATLAB. The procedure is composed of the leg trajectory planning, the generation of balancing trajectory, and the verification of dynamic stability.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2032-2035
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• 2003

This paper focused on the possibility of face recognition using Flexible let Point Setting method in Gabor Filter Based Face Recognition. Gabor Filter is very sensible to the Texture variation. Therefore, any little change in the face expression or rotation of posture make recognition rate down significantly. A suggested solution for this problem is the Flexible Jet Point Setting. A significant effect of this method is that the number of Jet Point has been reduced from over 150 to under 30 even though the change of recognition rate between two methods is neglectable, Furthermore a set of feature values which results from a set of Gabor filtering became insensible to face variation such as expression, rotation, and light effect. Retinex Algorithm which has been developed by NASA are used as pre-processing.

• 전자공학회논문지CI
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• 제48권3호
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• pp.46-53
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• 2011

본 논문에서는 대표적인 특징점 추출 알고리즘인 SURF (Speeded Up Robust Features)를 이용한 얼굴 인식 방법을 소개한 다. 일반적으로, SURF를 이용한 물체 인식은 특징점 추출 및 정합만을 수행하지만, 본 논문에서 제안하는 SURF를 이용한 얼굴 인식 방법은 특징점 추출 및 정합뿐만 아니라 얼굴 영상 회전 및 특징점 검증을 추가로 수행한다. 얼굴 영상 회전은 특징점의 수를 증가시키기 위해 수행되며, 특징점 검증은 정확하게 정합된 특징점들을 찾기 위해 수행된다. 비록 본 논문에서 제안한 SURF를 이용한 얼굴 인식 방법은 PCA를 이용한 방법보다 연산 시간이 더 요구되었지만, 인식률은 보다 더 높았다. 이러한 실험 결과를 통해, 특징점 추출 알고리즘도 얼굴 인식에 적용할 수 있음을 확인할 수 있었다.

• 한국운동역학회지
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• 제16권1호
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• pp.55-63
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• 2006

The purpose of this study is to prove the kinematical characteristics of Deff motion, the high bar performance, in terms of flying phases so that we can provide basic sources for improving gymnastic performance. To do this, we selected and analyzed the performance of two athletes who did Deff motion in the high bar competition of male artistic gymnastic in the 22nd Universiade 2003 Daegu. We drew the conclusions from the kinematical factors that were came out through analyzing three-dimensional cinematography of the athletes' movements, by using a high speed video camera. To make a successful performance, a performer releases the bar at a height of a high bar vertically and at a height of 82cm horizontally, and the flying performance should be made without moving forward, as maintaining the proper balance, in order to rise over 118cm high during the flying phase. When the performer is releasing the bar, an increase of the vertical speed in the center of the body and extension of a knee joint and a hip joint contribute to increasing a flying height. And when the moving body is twisted, leaning to left side is caused by the winding movement of a knee joint, which causes an unstable bar grasp. To grasp the bar stably, just before releasing the performer should gain propulsive force from twisting rotation through increasing the speed of shoulder rotation. And before the peak point, the performer should make sure of a body rotation distance over $164^{\circ}$ so that he or she can do an aerial rotary performance smoothly. When grasping the high bar, the center of the body should be above the bar and the angle of shoulder rotation should be maintained close to $540^{\circ}$ simultaneously. he high point performance(S1) has more speed on an ascending phase and less speed on a descending phase than the low point performance (S2). At the peak point, both the rotation angle of the body and that of the shoulder in high point performance are big as well. In conclusion, it is shown that a performer can make a jump toward the high bar easily with the body straight because the performer can hold the upper part of the body erect early in a descending phase.

• 한국지반공학회논문집
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• 제32권1호
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• pp.5-18
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• 2016

본 연구에서는 모형실험을 통해 균질모래지반에 매설된 횡력을 받는 무리말뚝의 수평저항력을 산정하는데 가장 큰 영향을 주는 배면토의 저항형태를 파악하였다. 저항거동 형태는 회전절점, 쐐기 파괴각, 쐐기 날개각으로 파악하였다. 실험은 지반의 상대밀도, 말뚝의 폭, 말뚝의 간격과 배열을 달리하여 수행하였다. 그 결과 직렬말뚝에서의 지반거동 양상은 전열과 중간열이 같았고 후열의 경우 전열과 중간열 보다 작은 값을 나타내었다. 병렬말뚝의 경우 지반거동 양상이 단독말뚝과 같게 나타났다. 실험 결과를 바탕으로 회전절점, 쐐기 파괴각, 쐐기 날개각 산정 값 들을 식으로 제안하였다.