• Title/Summary/Keyword: Curve detection

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Detection of the Optic Disk Boundary in Retinal Images Using Inward and Outward Curve Evolution (양방향 곡선 전개 방식을 이용한 망막영상에서의 시신경 원판 경계 검출)

  • Lee Sang-Kwan;Kim Seong-Kon
    • The Journal of the Korea Contents Association
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    • v.5 no.6
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    • pp.138-145
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    • 2005
  • This paper describes a technique for detecting the boundary of the optic disk in digital image of the retina using inward and outward curve evolution. This paper offers medical information about glaucoma progresses. For accurate boundary detection, image inpainting based on texture synthesis removes blood vessels crossing the optic disk. For removing noises and preserving boundary of optic disk in image inpainting process, the anisotropic diffusion filtering is necessary. After pre-processing, the optic disk boundary is determined using inward and outward curve evolution. The experimental results show that the algorithm is effective for detection of optic disk boundary.

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Automatic Detection of the Middle Tooth Crown Part for Full Automatic Tooth Segmentation in Dental CT Images

  • Lee, Chan-Woo;Chae, Ok-Sam
    • Journal of the Korea Society of Computer and Information
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    • v.23 no.3
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    • pp.17-23
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    • 2018
  • In this paper, we propose the automatic detection method which find the middle part of tooth crown to start individual tooth segmentation. There have been many studies on the automation of individual tooth segmentation, but there are still many problems for full automation. Detection of middle part of tooth crown used as initial information for individual tooth segmentation is closely related to performance, but most studies are based on the assumption that they are already known or they can be represented by using a straight line. In this study, we have found that the jawbone curve is similar to the tooth alignment curve by spatially analyzing the CT image, and propose a method to automatically detect the middle part of tooth crown. The proposed method successfully uses the jawbone curves to successfully create a tooth alignment curve that is difficult to detect. As the middle part of tooth crown is in the form of a tooth alignment curve, the proposed method detects the middle part of tooth crown successfully. It has also been verified by experiments that the proposed method works well on real dental CT images.

The Detection of Inflection Points on Planar Rational $B\'{e}zier$ Curves (평면 유리 $B\'{e}zier$곡선상의 변곡점 계산법)

  • 김덕수;이형주;장태범
    • Korean Journal of Computational Design and Engineering
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    • v.4 no.4
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    • pp.312-317
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    • 1999
  • An inflection point on a curve is a point where the curvature vanishes. An inflection point is useful for various geometric operations such as the approximation of curves and intersection points between curves or curve approximations. An inflection point on planar Bezier curves can be easily detected using a hodograph and a derivative of hodograph, since the closed from of hodograph is known. In the case of rational Bezier curves, for the detection of inflection point, it is needed to use the first and the second derivatives have higher degree and are more complex than those of non-rational Bezier curvet. This paper presents three methods to detect inflection points of rational Bezier curves. Since the algorithms avoid explicit derivations of the first and the second derivatives of rational Bezier curve to generate polynomial of relatively lower degree, they turn out to be rather efficient. Presented also in this paper is the theoretical analysis of the performances of the algorithms as well as the experimental result.

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Detection of Lane Curve Direction by Using Image Processing Based on Neural Network (차선의 회전 방향 인식을 위한 신경회로망 응용 화상처리)

  • 박종웅;장경영;이준웅
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.5
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    • pp.178-185
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    • 1999
  • Recently, Collision Warning System is developed to improve vehicle safety. This system chiefly uses radar. But the detected vehicle from radar must be decide whether it is the vehicle in the same lane of my vehicle or not. Therefore, Vision System is needed to detect traffic lane. As a preparative step, this study presents the development of algorithm to recognize traffic lane curve direction. That is, the Neural Network that can recognize traffic lane curve direction is constructed by using the information of short distance, middle distance, and decline of traffic lane. For this procedure, the relation between used information and traffic lane curve direction must be analyzed. As the result of application to sampled 2,000 frames, the rate of success is over 90%.t text here.

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Improvement of Spectrum Detection Algorithm for Mass Spectrometer (질량분석기를 위한 스펙트럼 검출 알고리즘의 개선)

  • Lee, Young Hawk;Choi, Hun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.1
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    • pp.47-54
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    • 2019
  • An improved method of spectrum detection algorithm for mass spectrum analysis system is proposed. In the conventional spectrum detection algorithm that utilizes the results of the linear approximation and quadratic curve fitting on the ion signal block of each mass index, it is possible to reduce the detection error in the mass spectrum detection by further improving the condition of eliminating the invalid ion signals. Also, the proposed method can reduce the estimation error of the peak value of the mass spectrum by using the result of quadratic curve fitting for the effective ion signal block in which the peak position error is corrected. To evaluate the effectiveness of the proposed method, computer simulations were carried out step by step using the measured ion signal. Also, by comparing the rate of false detection for several inputs, the proposed method showed better detection performance than the conventional method.

Estimating Characteristic Data of Target Acquisition Systems for Simulation Analysis (모의 분석을 위한 표적 획득 체계의 특성 데이터 산출)

  • Tae Yoon Kim;Sang Woo Han;Seung Man Kwon
    • Journal of the Korea Society for Simulation
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    • v.32 no.1
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    • pp.45-54
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    • 2023
  • Under combat simulation environment when inputting the detection performance data of the real system into the simulated object the given data affects the simulation analysis result. ACQUIRE-Target Task Performance Metric (TTPM)-Target Angular Size (TAS) model is used as a target acquisition model to simulate the detection ability of entities in the main combat simulation tool. This model estimates the decomposition curve of the object sensor and output the detection distance according to the target type. However, it is not easy to apply the performance of the new detection object that the user wants to input to the target acquisition model. Users want to input the detection distance into the target acquisition model, but the target acquisition model requires sensor decomposition curve data according to encounter conditions. In this paper, we propose a method of inversely deriving the sensor decomposition curve data of the target acquisition model by taking the detection distance to the target as an input. Here, the sensor decomposition curve data simultaneously satisfies each detection distance for three types of targets: personnel, ground vehicles, and aircraft. Finally, the detection distance of various reconnaissance equipment is applied to the detection object, and the detection effect according to the reconnaissance equipment is analyzed.

Improvement of Accuracy in Evaluating Hue Change Time in the Hue Detection Based Transient Liquid Crystals Technique (색상 검출방식의 천이 액정법에서 색상 변화 시간 산정의 정확도 향상)

  • Shin, So-Min;Jeon, Chang-Soo;Jung, Yong-Wun;Kwak, Jae-Su
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.11
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    • pp.918-925
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    • 2007
  • In this paper, different criteria fur determining hue change time in the hue detection based transient liquid crystals technique were compared. Results showed that methods utilizing threshold of intensity or saturation gave many missing points and quality of the calculated results were strongly depends on the value of threshold. Wider bandwidth in the hue bandwidth method showed better distribution of calculated hue change time, but induced ambiguity in the hue change time. In the time-hue curve fitting method, the distribution of evaluated hue change time was smooth and reasonable, and, by the nature of curve fitting, the noise effect on the hue was successfully considered in calculating of the hue change time. Compared to other methods, it is expected that the time-hue curve fitting method would provide better and accurate hue change time in the hue detection based transient liquid crystals technique.

Image saliency detection based on geodesic-like and boundary contrast maps

  • Guo, Yingchun;Liu, Yi;Ma, Runxin
    • ETRI Journal
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    • v.41 no.6
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    • pp.797-810
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    • 2019
  • Image saliency detection is the basis of perceptual image processing, which is significant to subsequent image processing methods. Most saliency detection methods can detect only a single object with a high-contrast background, but they have no effect on the extraction of a salient object from images with complex low-contrast backgrounds. With the prior knowledge, this paper proposes a method for detecting salient objects by combining the boundary contrast map and the geodesics-like maps. This method can highlight the foreground uniformly and extract the salient objects efficiently in images with low-contrast backgrounds. The classical receiver operating characteristics (ROC) curve, which compares the salient map with the ground truth map, does not reflect the human perception. An ROC curve with distance (distance receiver operating characteristic, DROC) is proposed in this paper, which takes the ROC curve closer to the human subjective perception. Experiments on three benchmark datasets and three low-contrast image datasets, with four evaluation methods including DROC, show that on comparing the eight state-of-the-art approaches, the proposed approach performs well.

SYBR Green I-based Real-time PCR Assay and Melting Curve Analysis for Rapid Detection of Staphylococcus aureus from Raw Milks Samples (Real-time PCR을 이용한 원유시료 유래 황색포도상구균의 신속 검출)

  • Jung, Jae-Hyuk;Jeong, Soon-Young;Lee, Sang-Jin;Choi, Sung-Sook
    • Journal of Food Hygiene and Safety
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    • v.23 no.2
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    • pp.121-128
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    • 2008
  • The aim of this study was to develop a LightCycler-based real time PCR (LC-PCR) assay and to evaluate its diagnostic use for the detection of Staphylococcus aureus in raw milk samples. Following amplification of 113 bp of coa gene encoding an coagulase precursor specific for Staphylococcus aureus, melting curve and DNA sequencing analysis was performed to verify the specificity of the PCR products. Amplification of 209 bp gene encoding an altered penicillin-binding protein, PBP2a (mecA), melting curve analysis and DNA sequencing analysis was performed to verify methicillin resistance Staphylococcus aureus (MRSA). According to this study, 6 of 647 raw milk samples showed S. aureus positive and 2 of them showed a mecA positive and the detection limit was 10 fg of DNA. And we also isolated Staphylococcus chromogenes a causative agent of exudative epidermitis in pigs and cattle from 3 samples.

Lane and Curvature Detection Algorithm based on the Curve Template Matching Method using Top View Image (탑뷰(top view) 영상을 이용한 곡선 템플릿 정합 기반 차선 및 곡률 검출 알고리즘)

  • Han, Sung-Ji;Han, Young-Joon;Hahn, Hern-Soo
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.47 no.6
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    • pp.97-106
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    • 2010
  • In this paper, lane and curvature detection algorithm based on the curve template matching method is proposed. To eliminate the perspective effect of the original image, the input image is transformed to a top view image. From this top view image, its edge image is created. To increase the accuracy of detection, a novel edge detection method, which shows a strength in lane detection, is proposed. In the first step, straight lanes are detected from the edge image, and then the Curve Template Matching(CTM) method is applied to detect the curved lanes and to find their curvatures. Since the proposed CTM method uses only the simple equations, such as line and circle equations, to detect the curved lane, the algorithm is simple. Moreover, we used the detected lane information in the previous frames to detect the current frame's lanes, the detection results become more reliable. The proposed algorithm has been tested in various road conditions (highway, urban street, night time highway, etc.). Experimental results show that the proposed algorithm can process about 70 frames per second with the successful lane detection rate over 95% and curvature detection rate about 90%.