• Title/Summary/Keyword: distortions

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A Comparative Study on Distortion Correction Algorithms for Digital Cadastral Maps (전산화 지적도의 왜곡 최소화 알고리즘 비교연구)

  • 김병국;정동훈;김해명
    • Spatial Information Research
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    • v.11 no.4
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    • pp.421-437
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    • 2003
  • In order to calculate the position of parcel boundary points, the area of the Parcel, and the length of the parcel boundary lines using a digitalized cadastral map or maps, the distortion of the map has to be corrected. The correction methods, such as the method of 2D affine transformation using 4 comer points of the edge lines, the method of tessellation into 9 subregions, the method of using the original surveying sheets, and the method of straightening the 4 edge lines, have been developed. In this Paper, the four methods were programed and applied to some sample cadastral maps and the correction accuracies were obtained and analysed. No method could prefectly correct the distortions because the distortions were irregular throughout the maps. However, it is found that tile method of straightening the 4 edge lines is the one which can minimize the distortions when the method is applied after applying the 2D projective transformation on the maps using the 4 comer points of the edges.

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A Restoration Method for Geometric Distortions to Improve Scanned Books Identification (스캔 도서 식별 성능 향상을 위한 기하하적 왜곡 복원 방법)

  • Kim, Doyoung;Lee, Sang-Hoon;Jadhav, Sagar;Lee, Sanghoon
    • Journal of Broadcast Engineering
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    • v.20 no.3
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    • pp.379-387
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    • 2015
  • In recent years, copyright violations from illegal copying and distribution of e-comic contents have become an important issue. Fingerprinting techniques have been emerged to provide a fast and reliable identification method of identifying e-comic contents. When illegally scanned or camera captured comic contents are distributed, they suffer from distortions. So the fingerprint differs from the original version. This paper presents a restoration framework for correcting geometric distortions in distorted comics to improve the comic content identification.

A Robust Reversible Data Hiding Scheme with Large Embedding Capacity and High Visual Quality

  • Munkbaatar, Doyoddorj;Park, Young-Ho;Rhee, Kyung-Hyune
    • Journal of Korea Multimedia Society
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    • v.15 no.7
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    • pp.891-902
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    • 2012
  • Reversible data hiding scheme is a form of steganography in which the secret embedding data can be retrieved from a stego image for the purpose of identification, copyright protection and making a covert channel. The reversible data hiding should satisfy that not only are the distortions due to artifacts against the cover image invisible but also it has large embedding capacity as far as possible. In this paper, we propose a robust reversible data hiding scheme by exploiting the differences between a center pixel and its neighboring pixels in each sub-block of the image to embed secret data into extra space. Moreover, our scheme enhances the embedding capacity and can recover the embedded data from the stego image without causing any perceptible distortions to the cover image. Simulation results show that our proposed scheme has lower visible distortions in the stego image and provides robustness to geometrical image manipulations, such as rotation and cropping operations.

A Study of Surrealistic Physical Distortion: Focused on Surrealism Formativeness (신체 왜곡패션에 관한 연구: 초현실주의(超現實主義) 조형성을 중심으로)

  • Kim, Minji;Kan, Hosup
    • Journal of Fashion Business
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    • v.17 no.5
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    • pp.70-83
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    • 2013
  • This study aims to analyze the physical distortions of fashion design which appear in the 20th century. People have been expressing the hope and beauty by twisting human body since the beginning of mankind. Each period has been showing different forms according to various social and cultural environments. The exaggerated body distortions from the primitive times to the modern are based on human body proportions. Such distortion is to emphasize the inherent beauty within the human body. However, the distortions of the body after the 20th century have been developed with the advent of surrealism which is not affected by reasons but by imaginations. Generally speaking, the reconstruction of the heterogeneous elements is allowed in art. The unexpected surreal elements are creating formative beauty using by distinctly different technique which is unfamiliar and awkward. Physical distortion creates other beauty that is not uniform and absolute beauty but it pursues the diversity of breaking down into categories. Formativeness of surreal physical distortion fashion has the potential for a variety of clothing design, therefore it has intrinsic values for continuous study.

Direct Correction of Lens Distortions in Close-Range Digital Photogrammetry (근거리 수치사진측량에 있어서 렌즈왜곡의 직접 보정)

  • 안기원;박병욱;서두천
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.17 no.3
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    • pp.257-264
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    • 1999
  • The lens distortions were corrected directly using the high-order polynomial which was offered in camera calibration data for the forward transformation and the root of Newton-Raphson's $2\times{2}$ nonlinear system for the backward transformation. The 0.04~0.08 pixels increase in accuracy was indicated through the use of direct correction of lens distortions instead of least square methods of commercial software. The least square adjustment method of high-order polynomial requires many control points which has a same weight. But this suggested method which is unnecessary to determine control points was developed and applied. The algorithm showed improved efficacy.

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An Optimally-Modified Multichannel Wiener Filter Using Speech Presence Probability (음성존재확률을 이용한 최적 변형 다채널 위너 필터)

  • Jeong, Sangbae;Kim, Youngil
    • Smart Media Journal
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    • v.7 no.3
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    • pp.9-15
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    • 2018
  • This paper proposes an optimal gain modification method of the Multichannel Wiener filter (MWF) using speech presence probabilities. Conventional gain modification methods of MWFs have the problem of the increase of speech distortions while reducing residual noises with its relative heuristic approach. However, the proposed optimal gain modification method, derived by solving the unconstrained minimization problem of the probability-involved cost function, reduces amounts of residual noises and signal distortions simultaneously. Through an evaluation of the filtered waveforms and spectrograms, it is verified that the proposed method results in an improved SNR with less signal distortions compared to the conventional MWF.

The Fiscal Policy Instruments and the Economic Prosperity in Jordan

  • ALZYADAT, Jumah A.;AL-NSOUR, Iyad A.
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.1
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    • pp.113-122
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    • 2021
  • This study aims to investigate the effects of fiscal policy instruments on economic growth in Jordan using annual data from 1970 to 2019, by applying the VAR model (Vector Auto regression) and the Vector Error Correction Model (VECM). The study also examines the dynamic relationship among economic variables over time using the Granger casualty test, Impulse Response Function, and Variance Decomposition. The results show that not only the public expenditures have a positive effect on economic growth in Jordan, but also the tax revenues positively affect the economic growth in the short-run, and this is because of using the tax revenues to finance the government activities in Jordan. This effect becomes negative in the long run, and this is explained because the tax seems a source of distortions in the economy, The extreme taxes may cause huge distortions in the economy, and these distortions destroys the purchasing power, the aggregate demand, and supply. More governmental dependence on tax revenues is the main source of tax evasion and less efficiency. The effect of taxation will curb any prosperity in the economy. Therefore, the government should estimate the fair tax rates to generate sufficient revenues to finance the public expenditure required to enhance economic prosperity.

Lateral torsional buckling of doubly-symmetric steel cellular I-Beams

  • Mehmet Fethi Ertenli;Erdal Erdal;Alper Buyukkaragoz;Ilker Kalkan;Ceyhun Aksoylu;Yasin Onuralp Ozkilic
    • Steel and Composite Structures
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    • v.46 no.5
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    • pp.709-718
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    • 2023
  • The absence of an important portion of the web plate in steel beams with multiple circular perforations, cellular beams, causes the web plate to undergo distortions prior to and during lateral torsional buckling (LTB). The conventional LTB equations in the codes and literature underestimate the buckling moments of cellular beams due to web distortions. The present study is an attempt to develop analytical methods for estimating the elastic buckling moments of cellular beams. The proposed methods rely on the reductions in the torsional and warping rigidities of the beams due to web distortions and the reductions in the weak-axis bending and torsional rigidities due to the presence of web openings. To test the accuracy of the analytical estimates from proposed solutions, a total of 114 finite element analyses were conducted for six different standard IPEO sections and varying unbraced lengths within the elastic limits. These analyses clearly indicated that the LTB solutions in the AISC 360-16 and AS4100:2020 codes overestimate the buckling loads of cellular beams within elastic limits, particularly at shorter span lengths. The LDB solutions in the literature and the Eurocode 3 LTB solution, on the other hand, provided conservative buckling moment estimates along the entire range of elastic buckling.