• 한국정보통신학회논문지
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• 제15권4호
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• pp.943-950
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• 2011

이 논문에서는 2D 및 3D 영상의 어텐션량을 측정하여 정지 및 동영상의 재설정 및 압축처리 기법을 제시하였다. 2D 어텐션은 세 개의 주요 구성, 즉, 영상의 세기, 컬러 및 방향성을 고려하였으며, 3D 영상에서 깊이 정보를 고려하였다. 시각적 어텐션은 관심있고 흥미있는 영역이나 객체를 검출하기 위해 희소성을 정량화하는 기법에 의해 구하였다. 왜곡된 스테레오 영상에서 변화된 깊이 정보를 어텐션 확률에 정합시켜서 최종적으로 저위 HVS 반응을 실제 어텐션 확률과 종합하여 스테레오 왜곡 예측기를 설계하였다. 결과로 기존 모델에 비해 효과적인 어텐션 기법을 개발하였으며 이를 비디오 재설정에 적용하여 성능을 입증하였다.

• 한국정밀공학회지
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• 제18권11호
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• pp.51-57
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• 2001

A light beam reflected from a machined surface generally containes information concerning about its surface roughness. This study examines and proposes a surface roughness measurement technique for on-machine measurement of machined surfaces. The technique is based on the measurement of a reflected laser beam pattern and the statistical analysis of its light intensity distribution. The surface roughness was found to be closely related to the standard deviation of the light intensity on the primary axis of the reflected pattern. An image acquisition device is made up of a laser diode, a half mirror, a screen, and a CCD camera. The exact image with the primary and secondary axes of a reflected laser beam pattern is calculated through such image processing algorithm as thresholding, edge detection, image rotation, segmentation, etc. A median filter and a surrounding light correction algorithm are improve the image quality and reduce the measuring error. Using the developed measuring device the effect of screen materials and workpiece and workpiece materials was investigated. Experimental results regarding to relatively high-quality surfaces machined by grinding, polishing, lapping processes have shown the measurement error is within 10% in the range of $0.1{mu}m~0.8{\mu}m R_q.$Therefore, the proposed method is thought to be effectively used when quick measurements is needed with workpieces fixed on the machine.

• IEIE Transactions on Smart Processing and Computing
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• 제1권2호
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• pp.78-87
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• 2012

In this paper, we address the tracking problem caused by camera motion and rolling shutter effects associated with CMOS sensors in consumer handheld cameras, such as mobile cameras, digital cameras, and digital camcorders. A modified particle filtering method is proposed for simultaneously tracking objects and compensating for the effects of camera motion. The proposed method uses an elastic registration algorithm (ER) that considers the global affine motion as well as the brightness and contrast between images, assuming that camera motion results in an affine transform of the image between two successive frames. By assuming that the camera motion is modeled globally by an affine transform, only the global affine model instead of the local model was considered. Only the brightness parameter was used in intensity variation. The contrast parameters used in the original ER algorithm were ignored because the change in illumination is small enough between temporally adjacent frames. The proposed particle filtering consists of the following four steps: (i) prediction step, (ii) compensating prediction state error based on camera motion estimation, (iii) update step and (iv) re-sampling step. A larger number of particles are needed when camera motion generates a prediction state error of an object at the prediction step. The proposed method robustly tracks the object of interest by compensating for the prediction state error using the affine motion model estimated from ER. Experimental results show that the proposed method outperforms the conventional particle filter, and can track moving objects robustly in consumer handheld imaging devices.

• 한국CDE학회논문집
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• 제17권3호
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• pp.208-215
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• 2012

Augmented reality can help to improve user's engineering abilities such as perception and decision making in industry field. Therefore we have studied on the maintenance-supporting applications for inspectors previously. The advantage of pre-existing marker system is that the making and using are easier than any other feature tracking and detection methods. However it must to be exposed to the sufficient light to be detected by computer image processing. The most of industry field is not in clean environment and there are not sufficient light as well. So, the normal marker system is not appropriated for industrial fields. This paper suggests RFID-based marker system to improve marker-detection ability in our AR maintenance system. RFID is not implemented by image processing but it is implemented by electromagnetic induction. Therefore we could more precisely detect markers even if the environment is low-light intensity condition.

• 정보처리학회논문지B
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• 제10B권6호
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• pp.629-638
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• 2003

본 논문에서는 인간시각에 대한 워터마크의 무감지성을 향상하고 워터마크를 제거하고자 하는 공격에 강인한 워터마킹 방법을 제안한다. 제안하는 방법은 워터마크를 삽입할 대상의 DCT 블록에 대한 인간의 시각적인 특성을 고려하여 워터마크의 삽입 여부와 블록에 삽입될 워터마크의 위치와 강도를 적응적으로 결정한다. 워터마크될 블록을 선택하기 위하여 사용되는 특징은 텍스쳐, 휘도, 대비이다. 본 논문은 제안된 방법의 성능을 평가하기 위하여 절단, 영상강화, 저주파 필터링, PEG 압축의 영상처리 공격에 대한 실험결과를 보인다.

• 융합신호처리학회논문지
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• 제7권4호
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• pp.169-177
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• 2006

이 논문의 목적은 X선의 감쇠를 이용한 측정에서 발생하는 여러 종류의 잡음을 효과적으로 제거하는데 적합한 영상재구성 방법을 제안하는 것이다. 구체적으로, X선의 방출기와 검출기의 필연적인 기계적 오류에 의해 발생하는 원형모양 오류와 전반적인 관측오차와 푸리에 변환기반 재구성 과정에서 나타나는 줄무늬 모양 잡음을 효과적으로 제거하기 위해 웨이블렛 방법을 제안한다. 원형모양 오류를 프로젝션에서 제거하기 위해 해당 잡음이 각도방향으로 강한 상관관계를 가지고 있음을 이용하여, 평균화된 정보에서 해당 잡음의 강도를 추정하고 이를 웨이블렛 축소법을 통해 제거하는 방법을 제안한다. 또한, 전반적인 잡음 제거와 영상재구성을 위해 웨이블렛-배규렛 분해법을 제안한다. 제안된 방법은 기존의 푸리에 변환을 기반으로 하는 방법에 비해 원형모양 오류와 영상재구성에 있어서 우수한 영상을 제공함을 시뮬레이션을 통해 확인하였다.

• 한국공작기계학회논문집
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• 제11권1호
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• pp.77-82
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• 2002

It is known that fractal theory has recently been used as a useful in the characterization of surface texture and the understanding of tribological phenomena such as friction wear and lubrication The fractal based method for describing the rubbed surface texture has aroused great interest In this paper the fractal descriptors was applied to rubbed surface of hydraulic driving material with image processing system in order to describe morphology of the rubbed surface The results showed that the fractal dimension can be determined by sum of intensity difference of surface pixel. The two step size to get fractal dimension is similar to surface roughness Ra. Fractal dimensions of the rubbed surfaces increase with an increase of applied load Morphology of the rubbed surface driving in lubricant can be effectively obtained by fractal dimensions.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.368-375
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• 2010

Unlike document images, license plate images are mostly captured under uneven lighting conditions. In particular, a shadowed region has sharp intensity variation and sometimes that region has very high intensity by reflected light. This paper presents a new technique for thresholding license plate images. This approach consists of three parts. In the first part, it performs a rough thresholding and classifies the type of license plate to adjust some parameters optimally. Next, it identifies a shadow type and binarizes license plate images by adjusting the window size and location according to the shadow type. And finally, post-processing based on the cluster analysis is performed. Experimental results show that the proposed method outperformed five well-known methods.

• Journal of International Society for Simulation Surgery
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• 제1권2호
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• pp.75-79
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• 2014

Purpose The region growing has a critical problem that it often extract vessels with unexpected objects such as a bone which has a similar intensity characteristics to the vessel. We propose the new method to extract arterial vascular anatomy around the stomach from the CTA volume without the post-processing. Materials and Methods Our method, which is also based on the region growing, requires the two seed points from the use. I automatically extracts perigastric arteries using the adaptive region growing method and it does not need any post-processing. Results The three region growing based methods are used to extract perigastric arteries - the conventional region growings with restrict and loose thresholds each and the proposed method. The 3D visualization from the result of our method shows our method extracted the all required arteries for gastric surgery. Conclusion By extracting perigastric arteries using the proposed method, over-segmentation problem that unexpected anatomical objects such as a rib or backbone are also segmented does not occurs anymore. The proposed method does not need to sensitively determine the thresholds of the similarity function. By visualizing the result, the preoperative simulation of arterial vascular anatomy around the stomach can be possible.

• 한국정밀공학회지
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• 제21권4호
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• pp.194-201
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• 2004

Optical fibers are indispensable fer optical communication systems that transmit large volumes of data at high speed. But the aligning technology under the sub-micron accuracy is required for the precise axis adjustment and connection. For the purpose of precise alignment of the optical arrays, in this research, we have developed the 12-axis(with 8 automated axis and 4 manual axis) automatic optical fiber alignment system including the image processing-based searching system, the automatic loading system using the robot and the suction toot and the automatic UV bonding system. In order to obtain the sub-micron alignment accuracy, two 4-axis PC-based motion controllers and the two 50nm resolution 6-aixs micro-stage actuated by micro stepping motors are adopted. The fiber aligning procedure consists of two steps. Firstly, the optical wave guide and an input optical array are aligned by the 6-axis input micro-stage with the IR camera. The image processing technique is introduced to reduce primary manual aligning time and result in achieving the 50% decrease of aligning time. Secondly, the IR camera is replaced by the output micro-stage and a wave guide and two optical arrays are aligned simultaneously before the laser power intensity delivered to the optical powermeter reached the threshold value. When the aligning procedure is finished, the wave guide and arrays are W bonded. The automatic loading/unloading system is also introduced and the entire wave guide handing time is reduced significantly compared to the former commercial aligning system.