• Title/Summary/Keyword: Curve detection

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Determination of cut-off value by receiver operating characteristic curve of norquetiapine and 9-hydroxyrisperidone concentrations in urine measured by LC-MS/MS

  • Kim, Seon Yeong;Shin, Dong Won;Kim, Jin Young
    • Analytical Science and Technology
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    • v.34 no.2
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    • pp.78-86
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    • 2021
  • The objective of this study was to investigate urinary cut-off concentrations of quetiapine and risperidone for distinction between normal and abnormal/non-takers who were being placed on probation. Liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was employed for determination of antipsychotic drugs in urine from mentally disordered probationers. The optimal cut-off values of antipsychotic drugs were calculated using receiver operating characteristic (ROC) curve analysis. The sensitivity and specificity of the method for the detection of antipsychotic drugs in urine were subsequently evaluated. The area under the ROC curve (AUC) was 0.927 for norquetiapine and 0.791 for 9-hydroxyrisperidone, respectively. These antipsychotic drugs are classified readily in the ROC curve analysis. The cut-off values for distinguishing regular and irregular/non-takers were 39.1 ng/mL for norquetiapine and 67.9 ng/mL for 9-hydroxyrisperidone, respectively. The results of this study suggest the cut-off values of quetiapine and risperidone were highly useful to distinguish regular takers from irregular/non-takers.

Line Detection Using Log Hough Transform (Log-Hough 변환을 이용한 직선검출)

  • 정헌상;황의봉
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.13 no.3
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    • pp.118-123
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    • 1999
  • Hough transform is well employed to retect or recognize the lines in image processing or in computer vision. Curve of the logarithm of ranges against the bearing does not change its shape according to data trints. This fact suggests that calculation cost can be remarkably reduced. An effective line detection algorithm is represented.sented.

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High Impedance Fault Detection Based on Wavelet Transform (웨이브렛 변환을 이용한 고저항 사고 검출)

  • Chung, Young-Sik;Kim, Dong-Wook
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.263-264
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    • 2008
  • A method for high impedance fault(HIF) detection based on wavelet transform is presented in this paper. HIF is detected and classified by obtaining the energy distribution curve from the wavelet coefficients at each level. The energy distribution of each transient disturbance has unique deviation from sinusoidal wave in particular energy level, which is adopted to provide reliable classification of the type of transient.

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Tracking of Moving Objects Using Levelset and Histogram (레벨 세트와 히스토그램을 이용한 이동 물체의 추적)

  • 박수형;염동훈;고기영;김두영
    • Proceedings of the IEEK Conference
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    • 2002.06d
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    • pp.137-140
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    • 2002
  • This paper presents a new variational framework for detecting and tracking moving objects in image sequence. Motion detection is performed using Level Set Model. The original frame is used to provide th moving object boundaries Then, the detection and the tracking problem are addressed in a common framework that employs a inward-outward curve evolution function. This function is minimized using a gradient decent method.

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Small Target Detection with Clutter Rejection using Stochastic Hypothesis Testing

  • Kang, Suk-Jong;Kim, Do-Jong;Ko, Jung-Ho;Bae, Hyeon-Deok
    • Journal of Korea Multimedia Society
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    • v.10 no.12
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    • pp.1559-1565
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    • 2007
  • The many target-detection methods that use forward-looking infrared (FUR) images can deal with large targets measuring $70{\times}40$ pixels, utilizing their shape features. However, detection small targets is difficult because they are more obscure and there are many target-like objects. Therefore, few studies have examined how to detect small targets consisting of fewer than $30{\times}10$ pixels. This paper presents a small target detection method using clutter rejection with stochastic hypothesis testing for FLIR imagery. The proposed algorithm consists of two stages; detection and clutter rejection. In the detection stage, the mean of the input FLIR image is first removed and then the image is segmented using Otsu's method. A closing operation is also applied during the detection stage in order to merge any single targets detected separately. Then, the residual of the clutters is eliminated using statistical hypothesis testing based on the t-test. Several FLIR images are used to prove the performance of the proposed algorithm. The experimental results show that the proposed algorithm accurately detects small targets (Jess than $30{\times}10$ pixels) with a low false alarm rate compared to the center-surround difference method using the receiver operating characteristics (ROC) curve.

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Multi-scale Diffusion-based Salient Object Detection with Background and Objectness Seeds

  • Yang, Sai;Liu, Fan;Chen, Juan;Xiao, Dibo;Zhu, Hairong
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.10
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    • pp.4976-4994
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    • 2018
  • The diffusion-based salient object detection methods have shown excellent detection results and more efficient computation in recent years. However, the current diffusion-based salient object detection methods still have disadvantage of detecting the object appearing at the image boundaries and different scales. To address the above mentioned issues, this paper proposes a multi-scale diffusion-based salient object detection algorithm with background and objectness seeds. In specific, the image is firstly over-segmented at several scales. Secondly, the background and objectness saliency of each superpixel is then calculated and fused in each scale. Thirdly, manifold ranking method is chosen to propagate the Bayessian fusion of background and objectness saliency to the whole image. Finally, the pixel-level saliency map is constructed by weighted summation of saliency values under different scales. We evaluate our salient object detection algorithm with other 24 state-of-the-art methods on four public benchmark datasets, i.e., ASD, SED1, SED2 and SOD. The results show that the proposed method performs favorably against 24 state-of-the-art salient object detection approaches in term of popular measures of PR curve and F-measure. And the visual comparison results also show that our method highlights the salient objects more effectively.

A Study of Runoff Curve Number Estimation Using Land Cover Classified by Artificial Neural Networks (신경망기법으로 분류한 토지피복도의 CN값 산정 적용성 검토)

  • Kim, Hong-Tae;Shin, Hyun-Suk
    • Journal of Korea Water Resources Association
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    • v.36 no.4
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    • pp.633-645
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    • 2003
  • The techniques of GIS and remote sensing are being applied to hydrology, geomorphology and various field of studies are performed by many researcher, related those techniques. In this paper, curve number change detection is tested according to soil map and land cover in mountain area. Neural networks method is applied for land cover classification and GIS for curve number calculation. The first, sample area are selected and tested land cover classification, NN(84.1%) is superior to MLC(80.9%). So we selected NN with land cover classifier. The second, curve number from the land cover by neural network classifier(57) is compared with that(curve number) from the land cover by manual work(55). Two values are so similar. The third, curve number classified by NN in sample area was applied and tested to whole study area. As results of this study, it is shown that curve number is more exact and efficient by using NN and GIS technique than by (using) manual work.

Dimensionality Reduction Methods Analysis of Hyperspectral Imagery for Unsupervised Change Detection of Multi-sensor Images (이종 영상 간의 무감독 변화탐지를 위한 초분광 영상의 차원 축소 방법 분석)

  • PARK, Hong-Lyun;PARK, Wan-Yong;PARK, Hyun-Chun;CHOI, Seok-Keun;CHOI, Jae-Wan;IM, Hon-Ryang
    • Journal of the Korean Association of Geographic Information Studies
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    • v.22 no.4
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    • pp.1-11
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    • 2019
  • With the development of remote sensing sensor technology, it has become possible to acquire satellite images with various spectral information. In particular, since the hyperspectral image is composed of continuous and narrow spectral wavelength, it can be effectively used in various fields such as land cover classification, target detection, and environment monitoring. Change detection techniques using remote sensing data are generally performed through differences of data with same dimensions. Therefore, it has a disadvantage that it is difficult to apply to heterogeneous sensors having different dimensions. In this study, we have developed a change detection method applicable to hyperspectral image and high spat ial resolution satellite image with different dimensions, and confirmed the applicability of the change detection method between heterogeneous images. For the application of the change detection method, the dimension of hyperspectral image was reduced by using correlation analysis and principal component analysis, and the change detection algorithm used CVA. The ROC curve and the AUC were calculated using the reference data for the evaluation of change detection performance. Experimental results show that the change detection performance is higher when using the image generated by adequate dimensionality reduction than the case using the original hyperspectral image.

Recovery of the connection relationship among planar objects

  • Yao, Fenghui;Shao, Guifeng;T amaki, Akikazu;Kato, Kiyoshi
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10a
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    • pp.430-433
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    • 1996
  • The shape of an object plays a very important role in pattern analysis and classification. Roughly, the researches on this topic can be classified into three fields, i.e. (i) edge detection, (ii) dominant points extraction, and (iii) shape recognition and classification. Many works have been done in these three fields. However, it is very seldom to see the research that discusses the connection relationship of objects. This problem is very important in robot assembly systems. Therefore, here we focus on this problem and discuss how to recover the connection relationship of planar objects. Our method is based on the partial curve identification algorithm. The experiment results show the efficiency and validity of this method.

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Characteristics of a Bimetal-Layer Chip of a Surface Plasmon Resonance Sensor in the Intensity Interrogation for Tumor Marker Detection

  • Kim, Hyungjin;Kim, Chang-duk;Sohn, Young-Soo
    • Journal of Sensor Science and Technology
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    • v.25 no.4
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    • pp.243-246
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    • 2016
  • The characteristics of a bimetallic surface plasmon resonance (SPR) chip were investigated to detect a tumor biomarker, carcinoembryonic antigen (CEA). The linewidth and the tangential slope of the reflectance curve of the bimetallic SPR chip was compared with those of the reflectance curve of a conventional gold (Au) SPR chip. The changes in reflectance in response to the variation in CEA in the critical concentration range were analyzed at an angle where the tangential slope of the reflectance curve was maximum. From linear regression analysis, the sensitivity of the bimetallic SPR chip with respect to the CEA in critical concentration was obtained.