• 한국ITS학회 논문지
• /
• 제12권6호
• /
• pp.78-86
• /
• 2013

본 논문에서는 효율적인 차량 영상 안정화를 위한 고성능 차량 영상 정보 시스템을 제안한다. 제안된 시스템은 움직임 추정 및 움직임 보상으로 분할하여 설계하였다. 움직임 추정은 지역 모션 벡터 추정 및 불규칙 지역 모션 검출, 전역 모션 벡터 추정으로 구성하였다. 움직임 보상은 추정된 전역 모션 벡터를 사용하여 차량의 영상 흔들림을 보상하기 위해 네 방향에 대하여 보정을 하였다. 설계된 알고리즘은 차량 영상 안정화를 위해 IP에 적용하여 움직임 보정 기술 칩을 설계하였다. 본 논문의 결과, 움직이는 물체에 대한 차량 영상 안정화는 메모리를 사용하지 않고 실시간 처리를 했기 때문에 다른 방법과 비교하여 효율성을 입증하였다. 또한, 블록 정합을 통한 연산으로 계산 시간 감소 효과를 얻었다.

• 대한의용생체공학회:의공학회지
• /
• 제28권1호
• /
• pp.95-101
• /
• 2007

Recently, small-animal imaging technology has been rapidly developed for longitudinal screening of laboratory animals such as mice and rats. One of newly developed imaging modalities for small animals is an x-ray micro-CT (computed tomography). We have developed two types of x-ray micro-CT systems for small animal imaging. Both systems use flat-panel x-ray detectors and micro-focus x-ray sources to obtain high spatial resolution of $10{\mu}m$. In spite of the relatively large field-of-view (FOV) of flat-panel detectors, the spatial resolution in the whole-body imaging of rats should be sacrificed down to the order of $100{\mu}m$ due to the limited number of x-ray detector pixels. Though the spatial resolution of cone-beam CTs can be improved by moving an object toward an x-ray source, the FOV should be reduced and the object size is also limited. To overcome the limitation of the object size and resolution, we introduce zoom-in micro-tomography for high-resolution imaging of a local region-of-interest (ROI) inside a large object. For zoom-in imaging, we use two kinds of projection data in combination, one from a full FOV scan of the whole object and the other from a limited FOV scan of the ROI. Both of our micro-CT systems have zoom-in micro-tomography capability. One of both is a micro-CT system with a fixed gantry mounted with an x-ray source and a detector. An imaged object is laid on a rotating table between a source and a detector. The other micro-CT system has a rotating gantry with a fixed object table, which makes whole scans without rotating an object. In this paper, we report the results of in vivo small animal study using the developed micro-CTs.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제15권12호
• /
• pp.4292-4307
• /
• 2021

For the research field of night infrared surveillance video, the target imaging in the video is easily affected by the light due to the characteristics of the active infrared camera and the classical ViBe algorithm has some problems for moving target extraction because of background misjudgment, noise interference, ghost shadow and so on. Therefore, an improved ViBe algorithm (I-ViBe) for moving target extraction in night infrared surveillance video is proposed in this paper. Firstly, the video frames are sampled and judged by the degree of light influence, and the video frame is divided into three situations: no light change, small light change, and severe light change. Secondly, the ViBe algorithm is extracted the moving target when there is no light change. The segmentation factor of the ViBe algorithm is adaptively changed to reduce the impact of the light on the ViBe algorithm when the light change is small. The moving target is extracted using the region growing algorithm improved by the image entropy in the differential image of the current frame and the background model when the illumination changes drastically. Based on the results of the simulation, the I-ViBe algorithm proposed has better robustness to the influence of illumination. When extracting moving targets at night the I-ViBe algorithm can make target extraction more accurate and provide more effective data for further night behavior recognition and target tracking.

• 전자공학회논문지
• /
• 제52권1호
• /
• pp.111-120
• /
• 2015

HDR(high dynamic range) 영상 생성은 실세계의 고명암비 영상을 재현하는 방법이다. Exposure fusion은 여러 HDR 영상 생성방법 중 한 가지로 true-HDR 영상을 생성하지 않고, 바로 pseudo-HDR 영상을 생성하는 방법이다. 그러나 노출이 다른 여러 입력영상들 중에서 이동하는 물체가 존재하면 잔상 효과가 발생하여 pseudo-HDR 영상의 화질 열화를 가져온다. 이러한 단점을 해결하기 위해 본 논문에서는 시간 영역에서 일치성 평가를 통한 무 잔상 exposure fusion을 제안하였다. 먼저 다중 역치 및 밝기를 이용한 비트맵과 색도 일관성 맵을 이용하여 각 입력 영상들간의 일치성을 평가하였고, 이를 시간 영역 가중치 맵으로 나타내었다. 그리고 기존 exposure fusion에서의 공간 영역 가중치 맵과 결합하여 최종 가중치 맵을 생성하였다. 마지막으로 각각 입력 영상에 최종 가중치 맵을 적용한 후, 합성하여 잔상이 제거된 pseudo-HDR 영상을 생성하였다. 실험을 통해 제안된 방법의 pseudo-HDR이 기존의 방법보다 잔상이 더 많이 제거되어 화질이 개선됨을 확인하였고, 객관적인 평가 방법인 기준 영상 대비 오차도 더 적게 나타남을 확인하였다.

• Journal of information and communication convergence engineering
• /
• 제13권4호
• /
• pp.275-279
• /
• 2015

There are several methods to record three dimensional (3D) information of objects such as lens array based integral imaging, synthetic aperture integral imaging (SAII), computer synthesized integral imaging (CSII), axially distributed image sensing (ADS), and axially distributed stereo image sensing (ADSS). ADSS method is capable of recording partially occluded 3D objects and reconstructing high-resolution slice plane images. In this paper, we present a computational method for depth extraction of partially occluded 3D objects using ADSS. In the proposed method, the high resolution elemental stereo image pairs are recorded by simply moving the stereo camera along the optical axis and the recorded elemental image pairs are used to reconstruct 3D slice images using the computational reconstruction algorithm. To extract depth information of partially occluded 3D object, we utilize the edge enhancement and simple block matching algorithm between two reconstructed slice image pair. To demonstrate the proposed method, we carry out the preliminary experiments and the results are presented.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2009년도 IWAIT
• /
• pp.158-163
• /
• 2009

In recent years, there has been increased interest in characterizing and extracting 3D information from 2D images for human tracking and identification. In this paper, we propose a single view-based framework for robust estimation of height and position. In the proposed method, 2D features of target object is back-projected into the 3D scene space where its coordinate system is given by a rectangular marker. Then the position and the height are estimated in the 3D space. In addition, geometric error caused by inaccurate projective mapping is corrected by using geometric constraints provided by the marker. The accuracy and the robustness of our technique are verified on the experimental results of several real video sequences from outdoor environments.

• 한국수산과학회지
• /
• 제46권3호
• /
• pp.273-281
• /
• 2013

The movement patterns of fish aggregations swimming freely near artificial reefs on August 24, 2006, at Suyeong Man, Busan, Korea, were acoustically investigated and analyzed. Acoustic surveys were conducted using a 70kHz split-beam echo sounder, 330 kHz side-scan sonar and a 310 kHz imaging sonar. Algorithms for tracking the movement of fish aggregations swimming in response to artificial reefs were developed. The travel direction and the swimming speed for two aggregations of fish were estimated from the trajectory orientations of echo responses recorded by the imaging sonar.The first group was floating just above the reef structure, while remaining in the midwater column, and the second group was swimming through and around artificial reefs near the seabed. The mean swimming speed was estimated to be 0.40 m/s for the midwater fish aggregation and 0.17 m/s for the bottom aggregation close to artificial reefs. These results suggest that the swimming behavior of fish aggregations passing close to artificial reefs near the seabed displayed a slower moving pattern than fish floating just above the reef structure in the midwater column.

• 대한원격탐사학회지
• /
• 제15권3호
• /
• pp.167-175
• /
• 1999

원격탐사 관련 핵심기술은 최근에 국방, 의료영상, 환경, 지질 등과 같은 광범위한 분야에서 활용범위를 확대하고 있다. 1cm ~ 수십 cm 파장의 파를 관측하는 마이크로파 원격탐사 기술은 반사 적외선 원격탐사나 열 적외선 원격탐사 기술에 비해 날씨조건과 밤낮에 관계없이 탐사를 수행할 수 있다는 장점을 가지고 있다. 마이크로파 영상레이다인 합성 개구 레이다를 이용한 영상화 방식은 응용목적에 따라 stripmap 방식, spotlight 방식, 그리고 inverse 방식으로 구분된다. 본 논문에서는 inverse 방식으로 지상에 고정된 레이다가 비행하는 항공체를 영상화하는 기법에 대해서 기술하였다. 비행 항공체의 영상화 기법은 자동 펴적인식 시스템 구축시 중요한 기술단계이며, 최근 이 분야에 대해 활발히 연구되고 있다. 비행 항공체를 영상화하기 위해 제안된 3가지 방식인 퓨리에 처리 기법, 시간-n 주파수 처리 기법, 그리고 투시로부터 복원 기법을 소개한 후, 각 방식의 장단점을 분석하였다.

• 한국의학물리학회지:의학물리
• /
• 제24권4호
• /
• pp.220-229
• /
• 2013

Respiratory-induced dynamic tumors render free-breathing cone-beam computed tomography (FBCBCT) images with motion artifacts complicating the task of quantifying the internal target volume (ITV). The purpose of this paper is to study the visibility of the revealed ITV when the imaging dose parameters, such as the kVp and mAs, are varied. The $Trilogy^{TM}$ linear accelerator with an On-Board Imaging ($OBI^{TM}$) system was used to acquire low-imaging-dose-mode (LIDM: 110 kVp, 20 mA, 20 ms/frame) and high-imaging-dose-mode (HIDM: 125 kVp, 80 mA, 25 ms/frame) FBCBCT images of a 3-cm diameter sphere (density=0.855 $g/cm^3$) moving in accordance to various sinusoidal breathing patterns, each with an unique inhalation-to-exhalation (I/E) ratio, amplitude, and period. In terms of image ITV contrast, there was a small overall average change of the ITV contrast when going from HIDM to LIDM of $6.5{\pm}5.1%$ for all breathing patterns. As for the ITV visible volume measurements, there was an insignificant difference between the ITV of both the LIDM- and HIDM-FBCBCT images with an average difference of $0.5{\pm}0.5%$, for all cases, despite the large difference in the imaging dose (approximately five-fold difference of ~0.8 and 4 cGy/scan). That indicates that the ITV visibility is not very sensitive to changes in imaging dose. However, both of the FBCBCT consistently underestimated the true ITV dimensions by up to 34.8% irrespective of the imaging dose mode due to significant motion artifacts, and thus, this imaging technique is not adequate to accurately visualize the ITV for image guidance. Due to the insignificant impact of imaging dose on ITV visibility, a plausible, alternative strategy would be to acquire more X-ray projections at the LIDM setting to allow 4DCBCT imaging to better define the ITV, and at the same time, maintain a reasonable imaging dose, i.e., comparable to a single HIDM-FBCBCT scan.

• 통합자연과학논문집
• /
• 제12권4호
• /
• pp.105-115
• /
• 2019

In this paper, a prediction system is proposed to control the brightness of smart street lamps by predicting the moving path through the reduction of consumption power and information of pedestrian's past moving direction while meeting the function of existing smart street lamps. The brightness of smart street lamps is adjusted by utilizing the walk tracking vector and soft hand-off characteristics obtained through the motion sensing sensor of smart street lamps. In addition, the motion vector is used to analyze and predict the pedestrian path, and the GPU is used for high-speed computation. Pedestrians were detected using adaptive Gaussian mixing, weighted difference imaging, and motion vectors, and motions of pedestrians were analyzed using the extracted motion vectors. The preprocessing process using linear interpolation is performed to improve the performance of the proposed prediction system. Fuzzy prediction system and neural network prediction system are designed in parallel to improve efficiency and rough set is used for error correction.