• Title/Summary/Keyword: extrema

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Image matching by Wavelet Local Extrema (웨이브릿 국부 최대-최소값을 이용한 영상 정합)

  • 박철진;김주영;고광식
    • Proceedings of the IEEK Conference
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    • pp.589-592
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    • 1999
  • Matching is a key problem in computer vision, image analysis and pattern recognition. In this paper a multiscale image matching algorithm by wavelet local extrema is proposed. This algorithm is based on the multiscale wavelet transform of the curvature which can utilize both the information of local extrema positions and magnitudes of transform results. This method has advantages in computational cost to a single scale image matching. It is also rotation-, translation-, and scale-independent image matching method. This matching can be used for the recognition of occluded objects.

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Zeros and Step Response Characteristics in LTI SISO Systems with Complex Poles (복소극점을 갖는 선형시불변 단일입출력 시스템의 영점과 계단응답 특성)

  • Lee, Sang-Yong
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.4
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    • pp.313-318
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    • 2010
  • This paper deals with the relationship between zeros and step response of the second and third order LTI (Linear Time Invariant) SISO (Single-Input and Single-Output) systems with complex poles. Although it has been known that the maximum number of local extrema is less than the number of zeros in the system with only real poles[8], some cases with complex poles are shown in this paper to have many local extrema. This paper proposes monotone nondecreasing conditions and describes the relationship between the transient response and the number of local extrema in step response with each region of zeros.

The Removal of Noisy Bands for Hyperion Data using Extrema (극단화소를 이용한 Hyperion 데이터의 노이즈 밴드제거)

  • Han, Dong-Yeob;Kim, Dae-Sung;Kim, Yong-Il
    • Korean Journal of Remote Sensing
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    • v.22 no.4
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    • pp.275-284
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    • 2006
  • The noise sources of a Hyperion image are mainly due to the atmospheric effects, the sensor's instrumental errors, and A/D conversion. Though uncalibrated, overlapping, and all deep water absorption bands generally are removed, there still exist noisy bands. The visual inspection for selecting clean and stable processing bands is a simple practice, but is a manual, inefficient, and subjective process. In this paper, we propose that the extrema ratio be used for noise estimation and unsupervised band selection. The extrema ratio was compared with existing SNR and entropy measures. First, Gaussian, salt and pepper, and Speckle noises were added to ALI (Advanced Land Imager) images with relatively low noises, and the relation of noise level and those measures was explored. Second, the unsupervised band selection was performed through the EM (Expectation-Maximization) algorithm of the measures which were extracted from a Hyperion images. The Hyperion data were classified into 5 categories according to the image quality by visual inspection, and used as the reference data. The experimental result showed that the extrema ratio could be used effectively for band selection of Hyperion images.

A Critical Analysis on an explanation for Monotonicity and Local Extrema of functions in Korean Mathematics Textbooks (우리나라 고등학교 수학 교과서에서 함수의 증감과 극대.극소를 설명하는 방식에 대한 비판적 논의)

  • Kye, Seung-Hyeok;Ha, Kil-Chan
    • The Mathematical Education
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    • v.49 no.2
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    • pp.247-257
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    • 2010
  • In this article an explanation of monotonicity of functions and the definition of local extrema in Korean highschool textbooks based on national curriculum(revised in 2007) are analyzed critically. On the basis of this analysis, we indicate some problems and propose its improvements.

Image Feature Extraction Using Energy field Analysis (에너지장 해석을 통한 영상 특징량 추출 방법 개발)

  • 김면희;이태영;이상룡
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.404-406
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    • 2002
  • In this paper, the method of image feature extraction is proposed. This method employ the energy field analysis, outlier removal algorithm and ring projection. Using this algorithm, we achieve rotation-translation-scale invariant feature extraction. The force field are exploited to automatically locate the extrema of a small number of potential energy wells and associated potential channels. The image feature is acquired from relationship of local extrema using the ring projection method.

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Recognition of Profile Contours of Human Face by Approximation - Recognition

  • Yang, Yun-Mo
    • Proceedings of the KIEE Conference
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    • pp.683-686
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    • 1988
  • In the recognition of similar patterns like profile contours of human faces, feature measure plays important role. We extracted effective and general feature by B-spline approximation. The nodes and vertices of the approximated curve are normalized and used as features. Since the features have both local property of curvature extrema and global property by B-spline approximation, they are superior to those of curvature extrema of the profile contour. For the image data of six sets of 56 persons, some of which are ill-made, averaged accuracy rate of 97.6 % is obtained in recognizing combinational 333 test samples.

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Extrema-based Band Selection for Hyperion Data (극단화소 기반의 Hyperion 데이터 밴드선택)

  • Han Dong-Yeop;Kim Dae-Sung;Kim Yong-Il
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • pp.193-198
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    • 2006
  • Among 242 Hyperion bands, there are 46 bands that contain completely no information and some other bands with various kinds of noise. It is mainly due to the atmosphenc absorption and the low signal-to-noise ratio. The visual inspection for selecting clean and stable bands is a simple practice, but is a manual, inefficient, and subjective Process. Though uncalibrated, overlapping, and all deep water absorption bands are removed, there still exist noisy bands. In this paper, we propose that the extrema ratio be measured for noise estimation and the unsupervised band selection be performed using the Expectation-Maximization algorithm. The Hyperion data were classified into 5 categories according to the image quality by visual inspection, and used as the reference data. The accuracy of the proposed method was compared with signal-to-noise ranking and entropy ranking. As a result, the proposed mettled was effective as preprocessing step for band selection.

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Zeros and Step Response αlaracteristics in LTI SISO Systems (선형시불변 단일입출력 시스템의 영점과 계단응답 특성)

  • Lee, Sang-Yong
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.8
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    • pp.804-811
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    • 2009
  • This paper deals with the relationship between zeros and step response of the second and third order LTI(Linear Time Invariant) SISO(Single-Input and Single-Output) systems. As well known, if a system has a single unstable zero, it shows the step response with undershoot and, on the other hand, a stable zero slower than the dominant pole causes the system to have the step response with overshoot. Generally, in the case of a system with two unstable real zeros, it is known to have B type undershoot[7]. But there are many complex cases of the step response extrema corresponding to zeros location in third order systems. This paper investigates the whole cases depending on DC gains of the additive equivalence systems and they are to be classified by the region of zeros which are related to the shape of the step response. Moreover, monotone nondecreasing conditions are proposed in the case of complex conjugate zeros as well as the case of two stable zeros.

Receiving Signal Level Measurement Based Weighting Method for Broadband Energy Detection (광대역 에너지 탐지를 위한 수신신호 강도 크기기반 가중치인가 기법)

  • Kang, TaeSu;Kim, Youngshin;Kim, Yong Guk;Moon, Sang-Taeck
    • The Journal of the Acoustical Society of Korea
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    • v.32 no.6
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    • pp.532-540
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    • 2013
  • In this paper, we propose the modified SED (Subband Energy Detection) which can assign weights adapting to the receiving signal level for the broadband energy detection in the passive SONARs. SED which is one of the broadband processing mainly employed by passive SONARs to detect a target is more robust against interference like multi signals or a clutter than CED (Conventional Energy Detection), but it degrades detection performance to assign weights independent of extracted extrema level of the receiving signal. Therefore, in this paper, the weighting method which can efficiently assigns rewards or penalties adapting to extracted extrema level of the receiving signal is proposed. In order to evaluate the performance of proposed method, we conducted experiments by using simulation and real ocean acoustic signal which is acquired from Yellow Sea. From the experiments, our proposed method has shown better performance than conventional SED.