• Title/Summary/Keyword: angular domain

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SECOND MAIN THEOREM FOR HOLOMORPHIC CURVES INTO ALGEBRAIC VARIETIES WITH THE MOVING TARGETS ON AN ANGULAR DOMAIN

  • Chen, Jiali;Zhang, Qingcai
    • Bulletin of the Korean Mathematical Society
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    • v.59 no.5
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    • pp.1191-1213
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    • 2022
  • In this paper, we will prove the second main theorem for holomorphic curves intersecting the moving hypersurfaces in subgeneral position with index on an angular domain. Our results are an extension of the previous second main theorems for holomorphic curves with moving targets on an angular domain.

Dictionary Learning based Superresolution on 4D Light Field Images (4차원 Light Field 영상에서 Dictionary Learning 기반 초해상도 알고리즘)

  • Lee, Seung-Jae;Park, In Kyu
    • Journal of Broadcast Engineering
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    • v.20 no.5
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    • pp.676-686
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    • 2015
  • A 4D light field image is represented in traditional 2D spatial domain and additional 2D angular domain. The 4D light field has a resolution limitation both in spatial and angular domains since 4D signals are captured by 2D CMOS sensor with limited resolution. In this paper, we propose a dictionary learning-based superresolution algorithm in 4D light field domain to overcome the resolution limitation. The proposed algorithm performs dictionary learning using a large number of extracted 4D light field patches. Then, a high resolution light field image is reconstructed from a low resolution input using the learned dictionary. In this paper, we reconstruct a 4D light field image to have double resolution both in spatial and angular domains. Experimental result shows that the proposed method outperforms the traditional method for the test images captured by a commercial light field camera, i.e. Lytro.

ON RADIAL OSCILLATION OF ENTIRE SOLUTIONS TO NONHOMOGENEOUS ALGEBRAIC DIFFERENTIAL EQUATIONS

  • Zhang, Guowei
    • Bulletin of the Korean Mathematical Society
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    • v.55 no.2
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    • pp.545-559
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    • 2018
  • In this paper we mainly investigate the properties of the solutions to a type of nonhomogeneous algebraic differential equation in an angular domain. It includes the Borel directions of the solutions, the width of angular domains in which the solutions take its order and the measure of radial distributions of Julia sets of the solutions.

An Analysis on the Reduction of Measurement Time Using Interpolation Algorithm in Near-field RCS Measurements for Aircraft Shape (항공기 형상에 대한 근전계 RCS 측정에서 내삽 알고리즘을 이용한 측정시간 단축에 대한 분석)

  • Park, Homin
    • Journal of the Korea Institute of Military Science and Technology
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    • v.25 no.4
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    • pp.339-346
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    • 2022
  • The importance of stealth technology is increasing in modern warfare, and Radar Cross Section(RCS) is widely used as an indicator of stealth technology. It is useful to measure RCS using an image-based near-field to far-field transformation algorithm in short-range monostatic conditions. However, the near-field measurement system requires a longer measurement time compared to other methods. In this work, it is proposed to reduce the measured data using an interpolation method in azimuth angular domain. The calculated far-field RCS values according to the sampling rate is shown, and the performance of the algorithm applied with interpolation in the angular domain is presented. It is shown that measurement samples can be reduced several times by using the redundancy in the angular domain while producing results similar to the conventional method.

Microwave Imaging of a Perfectly Conducting Cylinder by Using Modified Newton's Algorithm in the Angular Spectral Domain (각 스펙트럼 영역에서 개선된 Newton 알고리듬을 이용한 완전도체의 역산란 방법)

  • 박선규;박정석;라정웅
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.6
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    • pp.34-44
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    • 1994
  • In this paper, an iterative inversion method in angular spectral domain is presented for microwave imaging of a perfectly conducting cylinder. Angular spectra are calculated from measured far-field scattered fields. And then both the propagating modes and the evanescent modes are defined. The center and initial shape of an unknown conductor may be obtained by the characteristics of angular spectra and the total scattering cross section (TSCS). Finally, the orignal shape is reconstructed by the modified Newton algorithm. By using well estimated initial shape the local minima can be avoided, which might appear when the nonlinear equation is solved with Newton algorithm. It is shown to be robust to noise in scattered fields via numerical examples by keeping only the propagating modes and filtering out the evanescent modes.

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THE ZEROS DISTRIBUTION OF SOLUTIONS OF HIGHER ORDER DIFFERENTIAL EQUATIONS IN AN ANGULAR DOMAIN

  • Huang, Zhibo;Chen, Zongxuan
    • Bulletin of the Korean Mathematical Society
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    • v.47 no.3
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    • pp.443-454
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    • 2010
  • In this paper, we investigate the zeros distribution and Borel direction for the solutions of linear homogeneous differential equation $f^{(n)}+A_{n-2}(z)f^{(n-2)}+{\cdots}+A_1(z)f'+A_0(z)f=0(n{\geq}2)$ in an angular domain. Especially, we establish a relation between a cluster ray of zeros and Borel direction.

Deformation in transversely isotropic thermoelastic medium using new modified couple stress theory in frequency domain

  • Lata, Parveen;Kaur, Harpreet
    • Geomechanics and Engineering
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    • v.19 no.5
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    • pp.369-381
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    • 2019
  • The objective of this paper is to study the two dimensional deformation in transversely isotropic thermoelastic medium without energy dissipation due to time harmonic sources using new modified couple stress theory, a continuum theory capable to predict the size effects at micro/nano scale. The couple stress constitutive relationships have been introduced for transversely isotropic thermoelastic medium, in which the curvature tensor is asymmetric and the couple stress moment tensor is symmetric. Fourier transform technique is applied to obtain the solutions of the governing equations. Assuming the deformation to be harmonically time-dependent, the transformed solution is obtained in the frequency domain. The application of a time harmonic concentrated and distributed sources have been considered to show the utility of the solution obtained. The displacement components, stress components, temperature change and couple stress are obtained in the transformed domain. A numerical inversion technique has been used to obtain the solutions in the physical domain. The effects of angular frequency are depicted graphically on the resulted quantities.

Image registration using Hough transform and Phase correlation in Wavelet domain

  • Summar, Bhuttichai;Chitsobhuk, Orachat;Kasemsiri, Watjanapong
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2006-2009
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    • 2005
  • This paper presents a method for registering images using phase correlation technique in fourier domain, hough transform and multi-resolution wavelet. To register images, source and input images are transformed to wavelet domain. An angular transition can be obtained by applying hough transform technique followed by phase correlation. Then we apply phase correlation technique to find x-axis and y-axis transition. We apply wavelet transform to reduce processing time and also use its coefficients as edge information instead of canny detector. With multi-resolution property of wavelet transform, registration time can be greatly reduced. After we get all transition parameters, we transform the input images according to these parameters. Then, we compose and blend all images into a new large image with details of all source images. From our experiment, we can find the accurate transition both x-y translation and angular transition with less error.

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