• Title/Summary/Keyword: Phase reconstruction

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Reconstructing 3-D Facial Shape Based on SR Imagine

  • Hong, Yu-Jin;Kim, Jaewon;Kim, Ig-Jae
    • Journal of International Society for Simulation Surgery
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    • v.1 no.2
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    • pp.57-61
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    • 2014
  • We present a robust 3D facial reconstruction method using a single image generated by face-specific super resolution technique. Based on the several consecutive frames with low resolution, we generate a single high resolution image and a three dimensional facial model based on it. To do this, we apply PME method to compute patch similarities for SR after two-phase warping according to facial attributes. Based on the SRI, we extract facial features automatically and reconstruct 3D facial model with basis which selected adaptively according to facial statistical data less than a few seconds. Thereby, we can provide the facial image of various points of view which cannot be given by a single point of view of a camera.

A Two-Phase Approach of Progressive Mesh Reconstruction from Unorganized Point Clouds

  • Zhang, Hongxin;Liu, Hua;Hua, Wei;Bao, Hujun
    • International Journal of CAD/CAM
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    • v.7 no.1
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    • pp.103-112
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    • 2007
  • This paper presents a practical approach for surface reconstruction from unoriented point clouds. Instead of estimating local surface orientation, we first generate a set of depth images from the input point clouds, and a coarse mesh is then generated based on them by space carving techniques. The resultant mesh is progressively refined by local mesh refinement and optimization according to surface distance measure. A manifold mesh approximating the input points within an given tolerance is finally obtained. Our approach is easy to implement, but has the ability to outputs high quality meshes in different resolutions. We show that the proposed approach is not sensitive to several types of data disfigurement and is able to reconstruct models robustly from variance input data.

Comparison of Intracorporeal Reconstruction after Laparoscopic Distal Gastrectomy with Extracorporeal Reconstruction in the View of Learning Curve

  • Ahn, Chang Wook;Hur, Hoon;Han, Sang-Uk;Cho, Yong Kwan
    • Journal of Gastric Cancer
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    • v.13 no.1
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    • pp.34-43
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    • 2013
  • Purpose: The intracorporeal reconstruction after laparoscopic gastrectomy can minimize postoperative pain, and give better cosmetic effect, while it may have technical difficulties and require the learning curve. This study aimed to analyze the surgical outcome of intracorporeal reconstruction according to the surgeon's experience comparing with extracorporeal procedure. Materials and Methods: From January 2009 to September 2011, intracorporeal reconstruction in laparoscopic surgery for gastric cancer was performed for 71 patients (Intra group). During same period, 231 patients underwent laparoscopy-assisted gastrectomy (Extra group). These patients were classified into initial (1st to 20th case of intra group), intermediate (21th to 46th case), and experienced (after 47th case) phases. Results: Intracorporeal procedures included 35 cases of Billroth-I, 30 Billroth-II and 6 Roux en Y reconstructions. In the initial phase, operation time (P=0.022) were significantly longer for the patients of intra group than them of extra group. Although the difference was not significant, the length of hospital stay was longer and complication rate was higher in the intra group. In intermediate and experienced phases, there was no difference between two groups in operation time and hospital stay. In these phases, complication rate was lower in the intra group than the extra group (3.9% versus 9.7%). The pain scale was significantly lower post operation day 5 in the intra group. Conclusions: Intracorporeal reconstruction after laparoscopic distal gastrectomy was feasible and safe, and the technique was stabilized after 20th case if the surgeon has sufficient experiences when we compared it with extracorporeal reconstruction.

Electrical Resistance Tomography: Mesh Grouping and Boundary Estimation Algorithms

  • Kim Sin;Cho Hyo-Sung;Lee Bong-Soo
    • International Journal of Contents
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    • v.1 no.1
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    • pp.1-5
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    • 2005
  • This paper presents the development and application of electrical resistance imaging techniques for the visualization of two-phase flow fields. Two algorithms, the so-called the mesh grouping and the boundary estimation, are described for potential applications of electrical resistance tomography (ERT) and results from extensive numerical simulations are also presented. In the electrical resistance imaging for two-phase flows, numerical meshes fairly belonging to each phase can be grouped to improve the reconstruction performance. In many cases, the detection of phase boundary is a key subject and a mathematical model to estimate phase boundary can be formulated in a different manner. Our results indicated that the mesh grouping algorithm is effective to enhance computational performance and image quality, and boundary estimation algorithm to determine the phase boundary directly.

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Current Control of Three-Phase PWM Rectifiers without Phase Current Sensors (상전류 센서없는 3상 PWM 3상 정류기의 전류제어)

  • Im, Dae-Sik;Lee, Dong-Chun
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.2
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    • pp.123-129
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    • 2000
  • This paper proposes a novel current control method of three-phase PWM rectifiers using estimated currents without phase current sensors. The phase currents are reconstructed from switching states of the rectifier and the measured dc output currents. To eliminate the calculation time delay effect of the microprosessor, the current at the next sampling instant are predicted by a predictive state observer and then are used for feedback control. Experimental results show that the control performance of the proposed system is almost the same as that of the phase current sensor-based system.

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A Comparative Research on the Reconstruction and Remodeling of Low-rise, Dilapidated Apartment Buildings (노후저층 공동주택의 재건축과 리모델링 사업의 비교 연구)

  • 이효진;김동훈;김진호;임남기
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2002.05a
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    • pp.75-80
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    • 2002
  • The purpose of this study is to conduct researches on the aspects of reconstruction and remodeling of low-rise, dilapidated apartment buildings in the provinces, using comparative methodologies, consequently coming up with the findings in the following. 1) Unlike the rebuilding projects in which the movement process tends to be made in a bulk (in a simultaneous manner), it turns out that when it comes to remodeling, it would be advisable to attempt moving the inhabitants as a group either by the size of their residence or by the building. 2) Given the peculiarities of the construction management mechanism, remodeling projects might seem disadvantageous on the part of the management on account of inadequate accumulation of information and experience. Hence, based on the impeccable assessment of the current status of the subject buildings from the phase of planning, its imperative to closely look into and take into consideration a variety of direct and/or indirect factors in advance of the implementation. 3) A series of comparative researches from the perspective of economical efficiency that remodeling projects appear profitable considering the overall costs including financial expenses, varied taxes, and so on that will be eventually brought forth during the reconstruction period, and all the more so when allowing for the consequential effects which they ought to have upon the natural and human resources, environmental and ecological condition, business potentials, etc. Amelioration to be desired on the basis of the findings above.

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Principle of Rehabilitation after the Arthroscopic Anterior Cruciate Ligament Reconstruction (관절경적 전방 십자인대 재건술 후의 재활 치료 원칙)

  • Kyung Hee-Soo;Kim Hee-Soo
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.2 no.1
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    • pp.6-14
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    • 2003
  • The goal of rehabilitation after ACL reconstruction are return the patient to a reinjury level of activity with stable joint, removing pivot shift phenomenon, preservation of meniscus, restoration of range of motion, and minimize patello-femoral complication. The ACL reconstruction should avoid immediate surgery. The preoperative phase emphasizes two important factors. (1) The patient should have a resolution of knee swelling, a return of full ROM, and a normal gait. (2) The patient should be mentally prepared for the operation and subsequent rehabilitation. The postoperative rehabilitation program emphasizes extension, closed kinetic chain function exercises. The regular follow-up is important.

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Implementation of incoherent triangular holography and numerical reconstruction of the complex hologram (인코히어런트 삼각 홀로그래피의 구현과 복소홀로그램의 수치적 복원)

  • 김수길;이병호;김은수;손정영
    • Korean Journal of Optics and Photonics
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    • v.8 no.2
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    • pp.99-106
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    • 1997
  • In this paper, we demonstrated, through experiment and numerical reconstruction, that the bias and the conjugate image, which are main drawbacks in incoherent holography, can be removed. By using wave plates of the modified triangular interferometer, which was made by adding simple passive devices to the conventional triangular interferometer, we adjusted the relative phase differences of two optical waves traveling in clockwise and counterclockwise. In this way, we obtained four intensity patterns, and then by manipulating the four intensity patterns electronically we obtained the complex hologram without bias and the conjugate image. Comparing numerical reconstruction results of the complex hologram with numerical reconstruction results of the hologram obtained from the conventional triangular interferometer, we demonstrated that bias and the conjugate image can be removed using the modified triangular interferometer.

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Structure-From-Motion Approach to the Reconstruction of Surfaces for Earthwork Planning

  • Nassar, Khaled;Jung, Young-Han
    • Journal of Construction Engineering and Project Management
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    • v.2 no.3
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    • pp.1-7
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    • 2012
  • The reconstruction of surfaces from unorganized point clouds can provide very useful information for construction managers. Although point clouds are generally created using 3D scanners, they can also be generated via the structure-from-motion technique using a sequence of images. Here we report a novel surface reconstruction technique for modeling and quantifying earthworks that can be used for preliminary planning, project updates and estimating of earthwork quantities, as well as embedded planning systems in construction equipment. The application of structure-from-motion techniques in earth works is examined and its advantages and limitations identified. Data from 23 earthwork excavation construction sites were collected and analyzed. 3D surface reconstructions during the construction phase were compared to the original land form. Similar experiments were conducted with piles of earth and the results analyzed to determine appropriate ranges of use for structure-from-motion surface reconstructions in earthwork applications. The technique was found to be most suited to pile of materials with volumes less than 2000 m3. Piles up to 10 m in height and with base areas up to $300m^2$ were also successfully reconstructed. These results should be of interest to contractors seeking to utilize new technology to optimize operational efficiency.

Characteristics of Optical Phase Conjugate Wave Generated by Self-Pumping in Photorefractive $BaTiO_3$ Single Crystal ($BaTiO_3$ 광굴절 결정에서 자기 펌핑에 의해 발생되는 위상공액파의 특성)

  • 이장두
    • Proceedings of the Optical Society of Korea Conference
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    • 1990.02a
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    • pp.157-161
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    • 1990
  • Self-pumped phase conjugation(SPPC) in BaTiO3 single crystal is experimentally investigated at a wavelength of 514.5nm from an Ar+ laser. The incident Gaussian beam enters the crystal as an extraordinary ray. The maximum SPPC reflectivity of 48% is obtained at incident angle 80 degree. the SPPC wave demonstrates good image reconstruction. The response time (r) of SPPC wave as a function of incident intensity is measured to be r=36$\times$I-0.79sec.

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