• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1995년도 추계학술대회 논문집
• /
• pp.1105-1109
• /
• 1995

A CCD-camera, which is structured with vision system, was used to realize automatic seam-tracking system and 3-D information which is needed to generate torch path, was obtained by using laser-slip beam. To extract laser strip and obtain welding-specific point, Adaptive Hough-transformation was used. Although the basic Hough transformation takes too much time to process image on line, it has a tendency to be robust to the noises as like spatter. For that reson, it was complemented with Adaptive Hough transformation to have an on-line processing ability for scanning a welding-specific point. the dead zone,where the sensing of weld line is impossible, is eliminated by rotating the camera with its rotating axis centered at welding torch. The camera angle is controlled so as to get the minimum image data for the sensing of weld line, hence the image processing time is reduced. The fuzzy controller is adapted to control the camera angle.

• 대한원격탐사학회지
• /
• 제31권2호
• /
• pp.171-182
• /
• 2015

본 연구는 실내 정밀 매핑과 정교한 영상 기반 서비스에 활용 가능한 실내의 입체 전방위 영상을 취득하는 시스템과 이에 대한 캘리브레이션 방법을 제안한다. 제안된 시스템은 회전식 스테레오 라인 카메라 방식으로 구성되며, 안정적인 입체시와 객체점의 정밀한 결정에 적합한 입체 전방위 영상을 제공한다. 또한, 제안된 시스템의 투영모델을 기반으로 캘리브레이션을 위한 수학적 모델을 도출한다. 이를 통해 캘리브레이션을 수행하여, 실내 공간에 대해 ${\pm}16cm$ 이내의 정확도로 객체점을 추정할 수 있었다. 제안된 시스템과 캘리브레이션 방법은 실내의 정밀한 3차원 모델링에 활용될 것이다.

• Journal of Welding and Joining
• /
• 제16권6호
• /
• pp.68-76
• /
• 1998

A CCD camera with a laser stripe was applied to realized the automatic weld seam tracking. The 3-dimensional information obtained from the vision system made it possible to generate the weld torch path. The adaptive Hough transformation was used to extract laser stripes an to obtain specific weld points. It takes relatively long time to process image on-line control using the basic control using the basic Hough transformation, but it has a tendency of robustness over the noises such as spatter. For this reason, it was complemented with adaptive Hough transformation to have an on-line processing ability for scanning specific weld points. The dead zone, where the sensing of weld line is impossible, was eliminated by rotating the camera with its rotating axis centered at the weld torch. When weld lines were detected, the camera angle was controlled in order to get the minimum image data for sensing of weld lines. Consequently, the image processing time was reduced.

• 한국측량학회지
• /
• 제30권2호
• /
• pp.211-221
• /
• 2012

회전식 라인 카메라로 취득한 전방위 영상을 실내 공간정보 서비스에 활용하려면 취득한 영상을 실내 좌표계를 기준으로 정교하게 참조할 수 있어야 한다. 이에 본 연구는 실내 전방위 영상의 외부표정요소 - 취득한 시점의 카메라의 위치와 자세를 정확하게 추정 할 수 있는 지오레퍼런싱 방법을 제안한다. 이를 위하여 먼저 회전식 라인 카메라를 기하학적으로 모델링하여 전방위 영상에 대한 공선방정식을 유도한다. 실내 기준점을 공선방정식에 적용하여 실내 전방위 영상의 외부표정요소를 추정한다. 실측데이터에 적용한 결과 외부표정요소의 위치는 1.4mm의 정밀도로, 자세는 $0.05^{\circ}$의 정밀도로 추정할 수 있었다. 수평방향으로 약3픽셀, 수직방향으로 약 10픽셀 정도의 잔차가 남아 있었다. 특히 수직방향으로는 렌즈의 왜곡에 의한 시스템적 오차가 포함되어 있는 것으로 분석되었고 이는 카메라 캘리브레이션을 통해 제거되야 할 것으로 판단된다. 제시된 방법을 이용하여 정밀하게 지오레퍼런싱된 전방위 영상으로부터 고해상도 실내 3차원 모델을 생성하고 이에 기반한 정교한 증강현실 서비스가 가능할 것으로 기대된다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2006년도 하계종합학술대회
• /
• pp.941-942
• /
• 2006

A depth measurement system to recognize 3D shape of objects using single camera, line laser and a rotating mirror has been investigated. The camera and the light source are fixed, facing the rotating mirror. The laser light is reflected by the mirror and projected to the scene objects whose locations are to be determined. The camera detects the laser light location on object surfaces through the same mirror. The scan over the area to be measured is done by mirror rotation. The Segmentation process of object recognition is performed using the depth data of restored 3D data. The Object recognition domain can be reduced by separating area of interest objects from complex background.

• 제어로봇시스템학회논문지
• /
• 제3권6호
• /
• pp.613-618
• /
• 1997

In this paper, we designed a line CCD camera for a flying image, which is composed of a line CCD sensor(2048 cells) and a rotating mirror, and investigated its optical properties. We also made the 3-D image from the flying image which is made of 2-D image being juxtaposed to 1-D images obtained by the camera, and performed the calibration to acquire high precision 3-D data. As a result, we obtained the 3-D measurement system using the slit type of laser projector is available to measure the high precision shape of objects.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.339-339
• /
• 2000

In this parer, a method of measuring the size of defects on the wall and restructing the defect image of 3-dimension is developed based on the tracking algorithm of a camera position which uses the inclination angle of line slit beam for overcoming the difficulty of the corresponding problem identifying the image point in the both image. In the experiments, an algorithm for estimating the horizontal angle of CCD camera is presented and validated by applying it to the measurement of area and length under the variations of both the distance and the angle of CCD camera. And its performance is compared to that of the rotating and mapping method of image which has the Euclidian distance.

• Journal of Biosystems Engineering
• /
• 제35권3호
• /
• pp.197-205
• /
• 2010

An automatic echelon feeder of brown rice was presented for quality inspection system using color image processing. A echelon feeder was developed with vibratory feeder and cylindrical indent singulator having oblique light. The vibratory feeder consisted of a hopper, electromagnetic vibrator and multichannel grooves and supply the grain sample to the singulator. The feeding performance such as feed rate, blocking frequency of the channel was dependent on the size of groove and vibration pattern. A cylindrical indent singulator consisted of a rotating cylinder, prisms and a tungsten-halogen light source. It delivered grain kernels under the camera in a echelon form and illuminate the kernels with oblique ray and ambient light. The size of the indents installed on the surface of the rotating cylinder was determined by the dimensions of the paddy and a small triangular prism was placed in each indent to apply $ 20^{\circ}$ oblique light to the grain kernel.

• Journal of Welding and Joining
• /
• 제14권1호
• /
• pp.99-106
• /
• 1996

Development of an automatic TIG welding system incorporating a vision sensor and torch control mechanism leads to an improved welding quality and greater production efficiency. The automatic welding system should be greatly restricted in its size and weight for the LNG(Liquefied Natural Gas) storage tank and also provide a unique torch rotating mechanism which keeps the torch tip in the constant position while the angle is changed continuously to maintain the welding torch substantially perpendicular to the weld line. The developed system is driven by two translation axes X, Z and one rotational axis. A moving line window method is adopted to the image recognition of the corrugated membranes with specular reflection. This method decides original laser stripe patterns in image which is affected by multi-reflection. A self-teaching algorithm, which guides the automatic welding machine with the information provided by the CCD camera without any previous learning of a reference trajectory, was developed for tracking the corrugated membrane of the LNG tank along the weld line.

• 한국멀티미디어학회논문지
• /
• 제21권2호
• /
• pp.181-187
• /
• 2018

Line-laser beams are used for depth measurement of welding beads along the circumference of a pipe. For this, first we project a line-laser beam on an rotating pipe and take a sequence of images of the beam projected on the pipe using a CCD camera. Second, the projected line laser beam in each image is detected, converted into a thin curve. Finally measure the distance between the thinned curve and an imaginary line. When a line-laser beam is projected to a rough metal surface such as arc welding beads, the beam is severely scattered. This severe scattering makes the thinned curve perturbed. In this paper, we propose a thinning method robust against scattering of line lasers. First, we extract a projected line laser beam region using an adaptive threshold. Second, we model a thinned curve with a spline curve with control points. Next, we adjust the control points to fit the curve to the projected line-laser beam. Finally, we take a weighted mean of thin curves on a sequence of image frames. Experiments shows that the proposed thinning method results in a thinning curve, which is smooth and fit to the projected line-laser beam with small error.