• Title/Summary/Keyword: Local threshold

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The Improved Watershed Algorithm using Adaptive Local Threshold (적응적 지역 임계치를 이용한 개선된 워터쉐드 알고리즘)

  • Lee Seok-Hee;Kwon Dong-Jin;Kwak Nae-Joung;Ahn Jae-Hyeong
    • Proceedings of the Korea Information Processing Society Conference
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    • 2004.11a
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    • pp.891-894
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    • 2004
  • This paper proposes an improved image segmentation algorithm by the watershed algorithm based on the local adaptive threshold on local minima search and the fixing threshold on label allocation. The previous watershed algorithm generates the problem of over-segmentation. The over-segmentation makes the boundary in the inaccuracy region by occurring around the object. In order to solve those problems we quantize the input color image by the vector quantization, remove noise and find the gradient image. We sorted local minima applying the local adaptive threshold on local minima search of the input color image. The simulation results show that the proposed algorithm controls over-segmentation and makes the fine boundary around segmented region applying the fixing threshold based on sorted local minima on label allocation.

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Optimizing Speed For Adaptive Local Thresholding Algorithm U sing Dynamic Programing

  • Due Duong Anh;Hong Du Tran Le;Duan Tran Duc
    • Proceedings of the IEEK Conference
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    • summer
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    • pp.438-441
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    • 2004
  • Image binarization using a global threshold value [3] performs at high speed, but usually results in undesired binary images when the source images are of poor quality. In such cases, adaptive local thresholding algorithms [1][2][3] are used to obtain better results, and the algorithm proposed by A.E.Savekis which chooses local threshold using fore­ground and background clustering [1] is one of the best thresholding algorithms. However, this algorithm runs slowly due to its re-computing threshold value of each central pixel in a local window MxM. In this paper, we present a dynamic programming approach for the step of calculating local threshold value that reduces many redundant computations and improves the execution speed significantly. Experiments show that our proposal improvement runs more ten times faster than the original algorithm.

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Blur Detection through Multinomial Logistic Regression based Adaptive Threshold

  • Mahmood, Muhammad Tariq;Siddiqui, Shahbaz Ahmed;Choi, Young Kyu
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.4
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    • pp.110-115
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    • 2019
  • Blur detection and segmentation play vital role in many computer vision applications. Among various methods, local binary pattern based methods provide reasonable blur detection results. However, in conventional local binary pattern based methods, the blur map is computed by using a fixed threshold irrespective of the type and level of blur. It may not be suitable for images with variations in imaging conditions and blur. In this paper we propose an effective method based on local binary pattern with adaptive threshold for blur detection. The adaptive threshold is computed based on the model learned through the multinomial logistic regression. The performance of the proposed method is evaluated using different datasets. The comparative analysis not only demonstrates the effectiveness of the proposed method but also exhibits it superiority over the existing methods.

Zerotree coding with local adaptive threshold (국부 적응 문턱값을 가지는 제로트리 부호화)

  • 엄일규;김유신;김재호
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.10
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    • pp.112-119
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    • 1997
  • Zerotreeimage coding is known as a simple and effective image comprssion algorithm. It has the property that the compression is generated in order of improtance. Conventionally, a fixed threshold is applied to the entire wavelet coefficients regardless of frequency and local features of an image. In this paper, we propose a new zerotree coding scheme with adaptive threshold. The adaptive threshold is determined by human visual characteristics. It is shown that the image quality of the proposed method is better than that of the conventional method.

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Plagiarism Detection among Source Codes using Adaptive Methods

  • Lee, Yun-Jung;Lim, Jin-Su;Ji, Jeong-Hoon;Cho, Hwaun-Gue;Woo, Gyun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.6
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    • pp.1627-1648
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    • 2012
  • We propose an adaptive method for detecting plagiarized pairs from a large set of source code. This method is adaptive in that it uses an adaptive algorithm and it provides an adaptive threshold for determining plagiarism. Conventional algorithms are based on greedy string tiling or on local alignments of two code strings. However, most of them are not adaptive; they do not consider the characteristics of the program set, thereby causing a problem for a program set in which all the programs are inherently similar. We propose adaptive local alignment-a variant of local alignment that uses an adaptive similarity matrix. Each entry of this matrix is the logarithm of the probabilities of the keywords based on their frequency in a given program set. We also propose an adaptive threshold based on the local outlier factor (LOF), which represents the likelihood of an entity being an outlier. Experimental results indicate that our method is more sensitive than JPlag, which uses greedy string tiling for detecting plagiarism-suspected code pairs. Further, the adaptive threshold based on the LOF is shown to be effective, and the detection performance shows high sensitivity with negligible loss of specificity, compared with that using a fixed threshold.

Comparison of the Effects of Luminous Lamp, and Nonluminous Lamp Radiation on Experimental Pain Threshold Sensitivity (발광·무광 적외선등 조사가 실험적 통증역치에 미치는 효과 비교)

  • Lim, In-Hyuk;Lee, Jeong-Weon;Cho, Su-Won
    • Physical Therapy Korea
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    • v.9 no.3
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    • pp.1-9
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    • 2002
  • The purpose of this study was to compare the experimental pain threshold when used in luminous lamp radiation and nonluminous lamp radiation with healthy person. Thirty normal subjects were randomly assigned two groups: a luminous lamp radiation group, and a nonluminous lamp radiation group. The infrared lamps were applied on L3 for thirty minutes. Each group was measured for experimental pain threshold and local temperature before, 15 and 30 minute radiation. For statistical differences in change of the experimental pain threshold and local temperature due to differences in lamp ray was compared using the independent t-test. And, General linear model for profile plots test was used. The results were as: 1. Local temperature was significantly increased in the nonluminous lamp group (p<.01). 2. Experimental pain thershold was significantly increased in the luminous lamp group (p<.05),(p<.01). This study indicate that luminous lamp radiation was more effects of increase experimental pain thershold than nonluminous lamp radiation. Further study is needed to compare the effects of after period radiation.

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Local Binary Pattern Based Defocus Blur Detection Using Adaptive Threshold

  • Mahmood, Muhammad Tariq;Choi, Young Kyu
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.3
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    • pp.7-11
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    • 2020
  • Enormous methods have been proposed for the detection and segmentation of blur and non-blur regions of the images. Due to the limited available information about the blur type, scenario and the level of blurriness, detection and segmentation is a challenging task. Hence, the performance of the blur measure operators is an essential factor and needs improvement to attain perfection. In this paper, we propose an effective blur measure based on the local binary pattern (LBP) with the adaptive threshold for blur detection. The sharpness metric developed based on LBP uses a fixed threshold irrespective of the blur type and level which may not be suitable for images with large variations in imaging conditions and blur type and level. Contradictory, the proposed measure uses an adaptive threshold for each image based on the image and the blur properties to generate an improved sharpness metric. The adaptive threshold is computed based on the model learned through the support vector machine (SVM). The performance of the proposed method is evaluated using a well-known dataset and compared with five state-of-the-art methods. The comparative analysis reveals that the proposed method performs significantly better qualitatively and quantitatively against all the methods.

A Cooperative K-out-of-n Spectrum Sensing Method Considering Optimal Threshold (최적의 임계값을 고려한 K-out-of-n 협력 스펙트럼 검출 기법)

  • Choi, Moon-Geun;Kong, Hyung-Yun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.8
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    • pp.761-767
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    • 2011
  • In this paper, to improve performance of spectrum sensing, we propose the method which can find optimal threshold based on power of PU(Primary User) signal. To find optimal threshold value, we will use mathematical method, and find threshold which can has lowest error probability. Each SU(Secondary User) use this threshold and All Su makes local decision. All Su Send local decision to FC(Fusion Center). In this paper we consider K-out-of-n rule to combining local decision. To make global decision value, FC find optimal n. In the FC. FC received local decision which has lowest error probability and using optimal n and these vaule. FC make global decision value. In this paper, to analysis performance proposed scheme, we simulate proposed scheme using matlab and compare with traditional OR Rule. As a result of simulation, we can know that preposed scheme can get a better performance than traditional OR rule.

Enhanced Transdermal Delivery of Procaine Hydrochloride by lontophoresis -Comparison of Synergic Effect of High Voltage Current and Ultrasound- (이온도입에 의한 염산프로카인의 경피전달 증대 -고전압전류 및 초음파 병행의 상승효과 비교-)

  • Lee, Jong-Sook;Kim, Kyoung-Won;Lee, Jae-Hyoung;Choi, Yeong-Wook;Lee, Jae-Hwi
    • Journal of Pharmaceutical Investigation
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    • v.36 no.3
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    • pp.185-192
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    • 2006
  • The purpose of this study was to determine the effects of iontophoresis on transdermal delivery of procaine hydrochloride in healthy volunteers, as well as to the synergic effect of high voltage current or ultrasound on the efficacy of transdermal delivery of iontophoresis. Forty healthy volunteers were randomly assigned to four groups topical application group (TA), iontophoresis group (IT), pre-treatment of high voltage current stimulation with iontophoresis (HVS + IT), and pre-treatment of ultrasound application with iontophoresis (US + IT). All subjects received procaine iontophoresis on the forearm using direct current with 4 mA f3r 15 minutes. All subject was measured the duration of local anesthesia, pressure pain threshold, pain perception threshold using rectangular wave at 0.2 ms, 1 ms, 50 ms of rectangular current stimulation after procaine iontophoresis. For comparisons of the sensory characteristics and efficacy of iontophoresis between the groups, an one-way ANOVA and Kruskal-Wallis were used. The significant difference the duration of local anesthesia were found between the groups (p<0.001). The local anesthetic duration of IT, HVS+IT were significantly longer than TA. Meanwhile, the local anesthetic duration of US+IT was significantly longer than HVS+IT, IT and TA group (p<0.05). Also, the pressure pain threshold, pain perception threshold at 0.2 ms, 1 ms, 50 ms were significant difference between the groups (p<0.001). All sensory characteristics including pressure pain threshold, pain perception threshold of IT, HVS+IT was significantly increased than TA, whereas, US+1T was significantly increased HVS+1T, IT and TA (p<0.05). This study showed that the procaine iontophoresis have increase the duration of local anesthesia concomitantly pressure pain threshold and pain perception threshold of sensory nerve fibers such as $A-{\beta}$, $A-{\delta}$ and C fiber. This findings suggest that the iontophoresis enhanced the transdermal delivery of drug ions in vivo. The combination of ultrasound application and iontophoresis synergized the transdermal delivery of drug ions. It is suggests that an electric field, mechanical and heating property of ultrasound may contribute to synergic effect due to temporary changes of structure in the stratum corneum.

Comparison of Cleansing Regimes for Efficacy and Comfort of Iontophoretic Transdermal Lidocaine Delivery (세정방법에 따른 국소마취제 이온도입의 효율과 편안감 비교)

  • Jeong, Myung-A;Song, In-Yong;Lee, Jae-Hyoung
    • The Journal of Korean Physical Therapy
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    • v.18 no.4
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    • pp.41-50
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    • 2006
  • Purpose: The purpose of this study was to determined that the efficacy and comfort of iontophoretic transdermal delivery of lidocaine by comparison of local anesthetic duration, sensory threshold, pain threshold and pain tolerance levels according to four different cleansing regimes. Methods: Forty healthy volunteers were randomly assigned to four groups; oil cleansing group, lotion cleansing group, solution cleansing group and alcohol cleansing group. All subjects were received lidocaine iontophoresis on the forearm using direct current with 4 mA for 10 minutes. All subjects were measured the duration of local anesthesia after lidocaine iontophoresis, also evaluated the sensory threshold, pain threshold and pain tolerance level during iontophoresis. For comparisons of the efficacy and the sensory characteristics of iontophoresis within the groups, an one-way ANOVA was used. Results: The duration of local anesthesia were found significant difference between groups (p<0.001). The anesthetic duration in solution and alcohol cleansing groups were significantly longer than oil and lotion cleansing group by post hoc (p<0.05). Statistically significant difference were noted in respect to all sensory characteristics such as sensory threshold, pain threshold and pain tolerance between groups (p<0.001). The sensory threshold in solution and alcohol cleansing group were significantly lower than oil and lotion cleansing group by post hoc using Duncan multiple range test (p<0.05). The pain threshold and pain tolerance in solution and alcohol cleansing group were significantly higher than oil and lotion cleansing group by post hoc (p<0.05). Conclusion: These results demonstrated that cleansing regimes have affected the efficacy and discomfort of iontophoretic transdermal delivery of lidocaine. These findings indicate that cleansing agents without oil ingredient contributed to more comfort, and more successful achievement of the iontophoretic transdermal delivery.

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