• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.471-474
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• 2002

A new stereoscopic PIV has been constructed using two CCD cameras, stereoscopic photogrammetry, and 3D-PTV principle. The capability of the developed stereoscopic PIV was verified through a test on the Standard Images which are provided on the website of VSJ. The arrangement of the two cameras was based on angular position For the acquisition of 3D velocity vectors, 2D velocity vectors were obtained using the gray-level cross-correlation method from the two camera images and they were matched stereoscopically. The wake of a circular cylinder was measured and turbulent properties were presented.

• 제어로봇시스템학회논문지
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• 제15권5호
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• pp.473-479
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• 2009

This paper proposes an efficient method to locate the automated guided vehicle (AGV) into a specific parking position using artificial visual landmark and vision-based algorithm. The landmark has comer features and a HSI color arrangement for robustness against illuminant variation. The landmark is attached to left of a parking spot under a crane. For parking, an AGV detects the landmark with CCD camera fixed to the AGV using Harris comer detector and matching descriptors of the comer features. After detecting the landmark, the AGV tracks the landmark using pyramidal Lucas-Kanade feature tracker and a refinement process. Then, the AGV decreases its speed and aligns its longitudinal position with the center of the landmark. The experiments showed the AGV parked accurately at the parking spot with small standard deviation of error under bright illumination and dark illumination.

• 패션비즈니스
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• 제16권5호
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• pp.207-219
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• 2012

It is intended to study the colors of work environment and the working clothes colors between humans and environment with application of the arrangement of working clothes colors to domestic machinery companies that play pivotal roles in the industry of Korea. The purpose of this study is to provide the foundation of color plan for the integrated environmental harmonization and the safety of industrial sites by analyzing the photographs of working clothes in the sires in consideration of the functions of colors (clearness, attention-getting, and safety) using the Faber Birren's Color Harmony and by analyzing the result of a questionnaire survey. The study was conducted by the method to shoot a worksite using a digital camera after wearing 24 sets of uniforms, which were developed by the color plan established in a previous study, in the same worksite. The shooting place was an outdoor steel sheet inspection site of D company, a machinery company in Changwon-si, Gyeongnam, and the intensity of illumination was 2400lux. 24 pieces of images were printed in 5x7 inch size and a questionnaire survey was performed at 5-point scale. The questionnaire survey was performed for 13 subjects consisting of 6 field professionals having more than 30 years of experiences, 4 clothes color professionals, and 3 industrial engineering professionals. The result of the survey was statistically analyzed by the method of frequency analysis using IBM SPSS Statistics 20 Program. As the result of assessment of basic four colors (yellow green, sky blue, blue, and violet) of working clothes, yellow green, sky blue, and blue showed high mean values in (Tint)+(Shade)+(Tone)+(Gray) equation indicating that its is a harmonized equation.

• 인터넷정보학회논문지
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• 제4권6호
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• pp.57-67
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• 2003

최근 멀티미디어 처리 기술과 광학 기술의 발달과 더불어 얼굴 영상 정보를 이용한 응용 시스템에 대한 관심이 증대되고 있다. 기존의 얼굴 정보와 관련한 연구들은 대부분 정면 영상을 해석하여 사람을 식별하거나 영상의 표정을 분석하는데 초점을 두어왔으며 임의의 얼굴 영상의 방향성에 대한 연구는 부족한 실정이다. 특히, 한대의 카메라로 연속 촬영된 이미지들을 이용하는 기존의 방향성 검출 기법에서는 초기 영상이 정면 영상이어야 하는 제약점을 가진다. 본 논문에서는 얼굴의 특징 정보를 이용하여 임의의 얼굴 영상의 방항성을 검출하는 기법을 제안한다. 제안된 기법에서는 두 눈과 입술의 특징점을 기반으로 얼굴 사다리꼴을 정의하고, 얼굴 사다리꼴의 좌$.$우 면적을 비교한 통계 데이터를 이용하여 얼굴 영상의 좌.우 방향성을 계산하는 방향성 함수를 정의한다. 제안된 얼굴 영상의 검출 기법은 얼굴 영상의 방향성에 따라 얼굴 영상의 좌$.$우 여백을 안정적으로 설정하는 영상의 자동 배치 응용에 효과적으로 활용될 수 있다.

• 한국측량학회지
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• 제5권2호
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• pp.37-46
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• 1987

단사진을 이용한 측량은 교통, 산업, 산림, 범죄수사 및 일상생활에서 많은 활용면이 있으므로 본 논문에서는 이와같은 단사진 측량방법중 공간후방교회법(Space Resection)을 이용하는 방법과 2차원 사영변환을 이용하는 방법으로 나누어 해석기법을 제시하였다. 또한 측량용 비측량용 사진기를 사용한 단사진의 정확도를 비교분석 하였으며, 정확도를 향상시킬 수 있는 최적의 상태를 알기 위하여 기준점 수 및 배치형태를 변화시키면서 좌표 및 길이의 오차에 대하여 분석하였다. 그 결과 초점거리가 긴 측량용사진기 Wild P31이나 중형사진기 ASAHI PENTAX 6$\times$7의 경우 기준점 수 및 배치형태가 오차에 미치는 영향이 작았으나 초점거리가 짧은 비측량용 사진기 NIKON FM2는 기준점수 및 배치형태가 오차에 미치는 영향이 컸다. 따라서 이러한 단점을 극복하고 오차가 수렴하기 위해서는 최소한 기준점수 6점 이상을 측량대상 지역에 고루 분포시키고 또한 측량대상물을 촬영축에 직각방향으로 배치하여야 한다는 것을 알 수 있었다.

• 방송공학회논문지
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• 제20권6호
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• pp.912-920
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• 2015

일반적인 텍스처 기반의 특징 기술 알고리즘과 달리 LLAH 알고리즘은 이웃 특징 사이의 기하 관계에 기반하여 특징을 기술하기 때문에, 텍스처가 부족한 장면이나 카메라 포즈 변화가 큰 경우에 대해서도 특징을 기술 및 추적할 수 있으며, 이를 활용한 증강현실 구현이 가능하다. 본 논문에서는 가우시안 잡음을 가지는 랜덤 점(= 특징) 추적을 위한 LLAH 알고리즘의 성능을 최적화한다. 이를 위해 서로 다른 특징 수와 가우시안 잡음 크기를 가지는 영상에 대해 이웃 특징 수, 기하 불변자의 종류, 특징 사이의 거리에 따른 LLAH 알고리즘의 성능 변화를 분석하여 최적 조건을 결정한다. 결과적으로, 각 특징이 80% 이상의 매칭률을 가지고, 실시간으로 매칭 및 추적이 가능함을 확인하였다.

• 한국통신학회논문지
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• 제15권8호
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• pp.667-677
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• 1990

본 논문에서는 2차원 Hopfield 신경회로망 모델에 근거한 새로운 광 연산 메모리 시스템을 구현하였다. 2차원 영상의 실시간 처리를 위하여 입력 공간광변조기와 메모리 마스크는 상용 LCTV를 사용하고 특히, 4차원 메모리 행렬은 2차원 부행렬 마스크의 2차원적 배열로 구성하였으며 임의의 이력 패턴과 메모리 행렬간의 내적 계산은 multifocus hololens를 사용하여 처리하였다. 출력 영상은 전자적으로 thresholding 된 후 2차원 CCD 카메라를 사용하여 다시 연상 메모리 시스템의 입력으로 궤환되도록 루프를 구성하였다. 본 시스템의 연상 기억 및 오류 정정 능력에 대한 실험결과를 통해 본 논문에서 제시된 새로운 2차원 신경회로망 모델의 광학적 구현 시스템은 앞으로 패턴 인식, machine vision 등과 같은 분야에 실질적 응용이 가능하다.

• International Journal of Precision Engineering and Manufacturing
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• 제5권1호
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• pp.47-54
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• 2004

In this study, the electrorheological (ER) fluid was used as finishing agent. Since the apparent viscosity can be controlled by an electric field, the ER fluid can be one of efficient materials in finishing processes. To finish small 3-dimensional structures such as the aspherical surface in optical elements, the possible arrangement of a tool, part and auxiliary electrode was described. We examined the influence of the addition of a few abrasive particles on the performance of the ER fluid by measuring yield stress and observed the behavior of abrasive particles in the ER fluid by a CCD camera, which had been also theoretically predicted from the electromechanical principles of particles. On the basis of the above results, the steady flow analysis around the rotating micro tool was performed considering the non-uniform electric field. Finally, borosilicate glass was finished using the mixture of the ER fluid and abrasive particles and material removal with field strength and surface roughness were investigated.

• 한국생산제조학회지
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• 제22권3_1spc호
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• pp.607-614
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• 2013

This paper proposes a robot driving system and sensor implementation for use with an education robot. This robot has multiple functions and was designed so that children could use it with interest and ease. The robot recognizes the location of a user and follows that user at a specific distance when the robot and user communicate with each other. In this work, the robot was designed and manufactured to evaluate its performance. In addition, an embedded board was installed with the purpose of communicating with a smart phone, and a camera mounted on the robot allowed it to monitor the environment. To allow the robot to follow a moving user, a set of sensors combined with an RF module and ultrasonic sensors were adopted to measure the distance between the user and the robot. With the help of this ultrasonic sensors arrangement, the location of the user couldbe identified in all directions, which allowed the robot to follow the moving user at the desired distance. Experiments were carried out to see how well the user's location could be recognized and to investigate how accurately the robot trackedthe user, which eventually yielded a satisfactory performance.

• 대한치과보철학회지
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• 제43권1호
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• pp.120-131
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• 2005

Statement of problem. More than 70% of patients who need the implant supported restoration are parially edentulous. The principles of design for implant supported fixed partial denture in mandibular posterior region are many and varied. Jurisdiction for their use is usually based on clinical evaluation. There are several areas or interest regarding the design of implant supported fixed partial denture in mandibular posterior region. 1) Straight and tripod configuration in implant placement, 2) Two restoration types such as individualized and splinted restorations. Purpose. The purpose of this study was to compare the amount and distribution of stress around the implant fixtures placed in the mandibular posterior region with two different arrangements and to evaluate the effects of splinting using the photoelastic stress analysis. Material & methods. 1) Production of study model: Mandibular partially edentulous model was waxed-up and duplicated with silicone and two models were poured in stone. 2) Fixture installation and photoelastic model construction: Using surveyor(Ney, USh), 3 fixtures(two 4.0 $\times$13 mm, one 5.0$\times$10 mm, Lifecore, USA) were insta)led in straight & tripod configurations. Silicone molds were made and poured in photoelastic resin (PL-2. Measurements group, USA). 3) Prostheses construction: Four 3-unit bridges (Type III gold alloy, Dongmyung co., Korea) were produced with nonhexed and hexed UCLA abutments and fitted with conventional methods. The abutments were tightened with 30 Ncm torque and the static loads were applied at 12 points of the occlusal surface. 4) Photoelastic stress analysis : The polarizer analyzer system with digital camera(S-2 Pro, Fujifilm, Japan) was used to take the photoelastic fringes and analysed using computer analysis program. Results. Solitary hexed UCLA restoration developed different stress patterns between two implant arrangement configurations, but there were no stress transfer to adjacent implants from the loaded implant in both configurations. However splinted restorations showed lesser amount of stresses in the loaded implants and showed stress transfer to adjacent implants in both configurations. Solitary hexed UCLA restoration with tripod configuration developed higher stresses in anterior and middle implants under loading than implants with straight configurations. Splintied 3 unit fixed partial dentures with tripod configuration showed higher stress development in posterior implant under loading but there were no obvious differences between two configurations. Conclusions. The tripod configuration of implant arrangement didn't show any advantages over the straight configuration. Splinting of 3 unit bridges with nonhexed UCLA abutments showed less stress development around the fixtures. Solitary hexed UCLA restoration developed tilting of implant fixture under offset loads.