• Journal of Korea Multimedia Society
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• v.14 no.4
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• pp.529-537
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• 2011

In this paper, we propose a stable scale adaptive tracking method that uses centroids of the target colors. Most scale adaptive tracking methods have utilized histograms to determine target window sizes. However, in certain cases, histograms fail to provide good estimates of target sizes, for example, in the case of occlusion or the appearance of colors in the background that are similar to the target colors. This is due to the fact that histograms are related to the numbers of pixels that correspond to the target colors. Therefore, we propose the use of centroids that correspond to the target colors in the scale adaptation algorithm, since centroids are less sensitive to changes in the number of pixels that correspond to the target colors. Due to the spatial information inherent in centroids, a direct relationship can be established between centroids and the scale of target regions. Generally, after the zooming factors that correspond to all the target colors are calculated, the unreliable zooming factors are filtered out to produce a reliable zooming factor that determines the new scale of the target. Combined with the centroid based tracking algorithm, the proposed scale adaptation method results in a stable scale adaptive tracking algorithm. It tracks objects in a stable way, even when the background colors are similar to the colors of the object.

• Progress in Medical Physics
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• v.13 no.1
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• pp.15-20
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• 2002

Optimum field size for the whole body stereotactic radiosurgery was studied. Dose distributions from the various sizes of targets (diameter 1cm to 7cm, icm interval) were used for this study. Planing scores, expressed as the Target Coverage Index (TCI), were calculated for various target Margin ranged 0cm to 0.5cm. Highest scores were obtained for no Margin to the target size. The target Margin -0.5cm to 0cm to the target showed best TCI the cases of the target size larger than 6cm diameter. No Margin or 0.5cm Margin generated best TCI for less than 2cm cases. Prescription to 80~90% gives best results.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.37-37
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• 2003

목적 : 일반적으로 세기조절방사선치료 조사면의 작은 조각 크기에 대해, 이상적인 플루언스 지도 혹은 치료계획장치로부터의 최적화된 결과에 가까운 선량분포에서 더 좋은 leaf sequence를 얻을 수 있다. 한편, 치료중 장기의 움직임이 가장 작은 조각 크기의 선택을 방해하는 문제는 항상 존재한다. 게다가, 전통적인 정지 조사면과 달리 표적이 움직이는 동안 조사면 자체도 움직이므로 움직이는 표적에 대한 세기조절방사선치료의 경우에서 적절한 표적 마진에 관한 질문이 제기되어왔다. 따라서, 이 연구에서는 조각 크기에 대한 치료중 표적 움직임의 효과를 연구하였다. 대상 및 방법 : 세기조절방사선치료 플루언스 지도에 대해, 다양한 크기 - 0.5$\times$0.5, 1.0$\times$1.0, $1.5\times$1.5, 2.0$\times$2.0, 3.0$\times$3.0, 4.0$\times$4.0, 5.0$\times$5.0 $ extrm{cm}^2$ - 의 정사각형 패턴들을 설계하였고, Leaf sequence 는 step-and-shoot 빔 전달 방법을 이용하였다. 인접 조각들 사이의 세기 비율은 0.2, 0.4, 0.6, 0.8, 1.0로 하였고, 표적 움직임은 범위가 0.5-2.0 cm인 사인곡선 형태로 가정하였다. 움직임 묘사를 위해 동적 leaf 의 움직임이 표적의 움직임 을 반영하도록 계산되었고 움직임의 효과를 분석하기 위해 필름선량측정을 수행하였다. 결과 : 인접 조각의 세기 비율은 모든 경우에서 저하되었고, 호흡 진폭의 반보다 작은 조각 크기에 대한 선량분포는 임상적으로 유의할만큼 저하된 세기 지도를 보였다. 조각에 대해 방사선 조사시간의 두 호흡주기이상에 대해서는, 표적 마진 주위의 선량분포가 통상적인 정지 조사면에서와 같았다. 결론 : 플루언스 지도에서 세기조절방사선치료 조각의 최소 크기는 치료중 장기 움직임을 고려한 후 선택되어야 한다. 조각에 대한 방사선 조사시간의 두 호흡주기이상에 대해서는, 표적 마진을 기존의 정지 조사면과 같게 정의할 수 있었다.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.3
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• pp.130-135
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• 2012

In this paper, we propose a technique to detect the size and location of the small target in images by using Gaussian kernel repeatedly. In order to detect the size and location of the small target, we find the local maximum value by applying the facet model and then use the $3{\times}3$ Gaussian kernel repeatedly. we determine the size of small target by comparing the local maximum value $D_2$ according to the number of iteration. To reduce the computational complexity, we use the Gaussian pyramid when using the kernel repeatedly. Through the experiment, we verified that the size and location of the small target is detected by the number of iterations and results show improvements from conventional methods.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.2
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• pp.76-82
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• 2011

In this paper, we propose the technique to detect the location and size of the small target in multi-resolution image using cubic facet model. The input image is reduced by the multi-resolution and we obtain the multi-resolution images. We apply the facet model and the local maxima conditions to the multi-resolution images of each level. And then, we detect the location of the small target. We estimate that the location at the maximum of the $D_2$ which means the local maxima value of the facet model in the multi-resolution images is the location of the small target. We can detect the small target of the various size about the multi-resolution images of each level. In this paper, we experimented in the various infrared images with the small target. The method using the typical facet model applies a mask. However, the proposed method applies a mask in the multi-resolution images. We verified to vary the mask size and differ the size of the small target. The proposed algorithm can detect the location and size of the small target.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.565-566
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• 2023

적외선 영상에서 정확하게 표적을 포착하기 위해서는 수많은 거짓 표적과 참표적을 실시간으로 구별하고, 최종적으로 참 표적 하나만을 추적 할 수 있어야 한다. 본 논문에서는 추적 게이트의 이동거리 및 이동 방향을 실시간 감시하여 추적 게이트의 이상 움직임 유무를 확인하고, 추적 필터가 설정한 임계값 대비 높은 수치로 이동하거나, 한 방향이 아닌 다양한 방향으로 움직일 경우 해당 게이트를 신속하게 제거하여 거짓 표적에 대한 추적을 방지하도록 하였다. 또한 추적 게이트 이동 거리 및 확장 크기를 동적으로 조절함으로써 표적의 크기 변화와 표적의 움직임에 강인하게 추적 필터가 동작 되도록 설계하였다.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.885-901
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• 2021

This paper illustratesthe impact of the temporal gap between satellite images and targetsize in mesoscale atmospheric motion vector (AMV) algorithm. A test has been performed using GEO-KOMPSAT-2A (GK2A) rapid-scan data sets with a temporal gap varying between 2 and 10 minutes and a targetsize between 8×8 and 40×40. Resultsshow the variation of the number of AMVs produced, mean AMV speed, and validation scores as a function of temporal gap and target size. As a results, it was confirmed that the change in the number of vectors and the normalized root-mean squared vector difference (NRMSVD) became more pronounced when smaller targets are used. In addition, it was advantageous to use shorter temporal gap and smaller target size for the AMV calculation in the lower layer, where the average speed is low and the spatio-temporal scale of atmospheric phenomena is small. The temporal gap and the targetsize are closely related to the spatial and temporalscale of the atmospheric circulation to be observed with AMVs. Thus, selecting the target size and temporal gap for an optimum calculation of AMVsrequires considering them. This paper recommendsthat the optimized configuration to be used operationally for the near-real time analysis of mesoscale meteorological phenomena is 4-min temporal gap and 16×16 pixel target size, respectively.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.449-452
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• 2000

본 논문은 다중의 사람을 동시에 검지 및 추적하기 위한 방법을 제안한다 여러 명의 검지된 사람들이 교차해서 움직이거나 폐색(occlusion) 되어 움직이는 경우 이를 검지하고 신뢰적으로 추적하기 위한 방법을 제시한다. 카메라의 시야 범위 안에 나타난 표적은 일정한 크기를 가지는 오브젝트이므로, 배경영상에서 전경 영상만을 분리하는 과정에서 오브젝트의 크기를 고려하여 표적을 검지 한다. 표적의 검지는 환경적인 요인에 의한 부가요소에 적응적으로 대치하기 위해 적응적인 영상처리기법을 사용한다. 최종적으로 검지 된 표적을 동시에 추적하기 위해 본 논문에서는 JPDA(Joint Probability Data Association) 필터를 이용하며 ,표적간의 폐색을 처리하기 위한 방법으로 전이모델을 첨가해서 사용한다. 다중 표적의 추적에 관한 실험의 유효성 및 강인함은 다양한 실제 영상의 실험을 통해 입증한다.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.4
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• pp.61-70
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• 2012

We propose a method that finds candidate targets based on morphology and detects a small target from them using modified gaussian distance function. The existing small target detection methods use predictive filters or morphology. The methods using predictive filters take long to approach least errors. The methods using morphology are weak at clutters and need to consider size of a small target when selecting size of structure elements. We propose a robust method for small target detection to complete the existing methods. First, the proposed method deletes clutters using a median filter. Next, it does closing and opening operation using various size of structure elements, and figures target candidate pixels with subtraction operation between the results of closing and opening operation. It detects an exact small target using a gaussian distance function from the candidates target areas. The proposed method is less sensitive to clutters, and shows a detection rate of 98%.

• Korean Journal of Cognitive Science
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• v.11 no.2
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• pp.37-51
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• 2000

The present study compared computer users target-selection response patterns when the targets were varied in terms of their relative location and distance from the current position of the cursor. In Experiment 1, where the mouse was used as an input device, the effects of different directions and distances of simple target(small rectangle) on target-selection response were investigated. The results of Experiment 1 can be summarized as follows: (1) Overshooting was more frequent than either undershooting or correct movement and (2) this tendency was more prominent when the targets were presented in the oblique direction or in farther location from the current cursor position. (3) Although the overshooting and undershooting were more frequent in the oblique direction, the degree of deviation was larger in horizontal and vertical direction. (4) Time spent in moving the mouse rather than that spent in planning, calibrating or clicking was found to be the most critical factor in determining total response time. In Experiment 2, effects of the font size and line-height of the target on target-selection response were compared with regard to two types of input devices(keyboard vs. mouse). The results are as follows: (1) Mouse generally yielded shorter target-selection time than keyboard. but this tendency was reversed when the targets were presented in horizontal and vertical directions. (2) In general, target-selection time was the longest in the condition of font size of 10 and line-height of 100%, and the shortest in the condition of font size of 12 and line-height of 150%. (3) When keyboard was used as the input device, target-selection time was shortest in the 150% line-height condition, whereas in the mouse condition, target-selection time tended to be increased as the line-height increased. which resulted in the significant interaction effect between input device and line-height. Finally, several issues relating to human-computer interaction were discussed based on the results of the present study.