• Current Optics and Photonics
• /
• 제8권3호
• /
• pp.246-258
• /
• 2024

In aerospace and energy engineering, the reconstruction of three-dimensional (3D) temperature distributions is crucial. Traditional methods like algebraic iterative reconstruction and filtered back-projection depend on voxel division for resolution. Our algorithm, blending deep learning with computer graphics rendering, converts 2D projections into light rays for uniform sampling, using a fully connected neural network to depict the 3D temperature field. Although effective in capturing internal details, it demands multiple cameras for varied angle projections, increasing cost and computational needs. We assess the impact of camera number on reconstruction accuracy and efficiency, conducting butane-flame simulations with different camera setups (6 to 18 cameras). The results show improved accuracy with more cameras, with 12 cameras achieving optimal computational efficiency (1.263) and low error rates. Verification experiments with 9, 12, and 15 cameras, using thermocouples, confirm that the 12-camera setup as the best, balancing efficiency and accuracy. This offers a feasible, cost-effective solution for real-world applications like engine testing and environmental monitoring, improving accuracy and resource management in temperature measurement.

• International Journal of CAD/CAM
• /
• 제7권1호
• /
• pp.103-112
• /
• 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.

• Current Optics and Photonics
• /
• 제5권3호
• /
• pp.322-328
• /
• 2021

In this paper, a pretreatment method for a matrix in convex optimization is proposed to optimize the spectral reconstruction process of a disordered dispersion spectrometer. Unlike the reconstruction process of traditional spectrometers using Fourier transforms, the reconstruction process of disordered dispersion spectrometers involves solving a large-scale matrix equation. However, since the matrices in the matrix equation are obtained through measurement, they contain uncertainties due to out of band signals, background noise, rounding errors, temperature variations and so on. It is difficult to solve such a matrix equation by using ordinary nonstationary iterative methods, owing to instability problems. Although the smoothing Tikhonov regularization approach has the ability to approximatively solve the matrix equation and reconstruct most simple spectral shapes, it still suffers the limitations of reconstructing complex and irregular spectral shapes that are commonly used to distinguish different elements of detected targets with mixed substances by characteristic spectral peaks. Therefore, we propose a special pretreatment method for a matrix in convex optimization, which has been proved to be useful for reducing the condition number of matrices in the equation. In comparison with the reconstructed spectra gotten by the previous ordinary iterative method, the spectra obtained by the pretreatment method show obvious accuracy.

• 전자공학회논문지B
• /
• 제31B권8호
• /
• pp.39-46
• /
• 1994

In this paper a state reconstruction filter for linear discrete-time stochastic systems with unknown inputs and noises is presented. The suggested filter can estimate the system state vector and the unknown inputs simultaneously As an extension of the filter a fault diagnosis filter for linear discrete-time stochastic systems with unknown inputs and noises is presented for each filters the optimal gain determination methods which minimize the variance of the state reconstruction errorare presented. Finally the usability of the filtersis shown via numerical examples.

• Smart Structures and Systems
• /
• 제14권2호
• /
• pp.145-158
• /
• 2014

The objective of this study is to improve the survivability and reliability of the FBG sensor network in the structural health monitoring (SHM) system. Therefore, a model reconstruction soft computing recognition algorithm based on support vector regression (SVR) is proposed to achieve the high reliability of the FBG sensor network, and the grid search algorithm is used to optimize the parameters of SVR model. Furthermore, in order to demonstrate the effectiveness of the proposed model reconstruction algorithm, a SHM system based on an eight-point fiber Bragg grating (FBG) sensor network is designed to monitor the foreign-object low velocity impact of a CFRP composite plate. Simultaneously, some sensors data are neglected to simulate different kinds of FBG sensor network failure modes, the predicting results are compared with non-reconstruction for the same failure mode. The comparative results indicate that the performance of the model reconstruction recognition algorithm based on SVR has more excellence than that of non-reconstruction, and the model reconstruction algorithm almost keeps the consistent predicting accuracy when no sensor, one sensor and two sensors are invalid in the FBG sensor network, thus the reliability is improved when there are FBG sensors are invalid in the structural health monitoring system.

• 한국진공학회지
• /
• 제1권1호
• /
• pp.83-87
• /
• 1992

최근 Angle Resolved Ultraviolet Photoemission Spectroscopy(ARUPS)를 통하여 Mo(011)과 W(011)의 surface Fermi contour에 관한 연구가 발표되었다. Hydrogen 흡착시 W(011)의 electron contour는 팽창하였다. 이것은 electron contour를 이루는 surface state가 hydrogen 흡착시 higher binding energy로 이동한 결과이다. Surface state의 higher binding energy로의 이동은 결국 band flattening으로 이해되며, 이 band flattening 에 S.E.Trullinger의 long range dipole dipole force와 Kohn anomaly 현상을 부합시켜 W(011) surface에 수소 흡착시 일어나는 reconstruction 현상에 대한 설명을 시도해 보았다.

• 한국전기전자재료학회논문지
• /
• 제13권9호
• /
• pp.781-785
• /
• 2000

Chalcogenide glasses are suggested as a candidate for optical recording. In this study, we have investigated the holography recording and reconstruction of the polarization state in chalcogenide As$_{40}$ Ge$_{10}$Se$_{15}$ S$_{35}$ thin films. We have used a He-Ne laser light(633nm) to probe and record of the grating. Also the polarization state of object beam was modulated with a λ/4 wave plate. The polarization state of the +1st order diffracted beam was generated by readout of the grating with a linearly polarized reference beam. It was the same-handed polarization state as the polarization state of the recording beam. The result is shown that the diffraction efficiency of circularly polarized recording represents higher than other polarization state.ate.e.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.312-315
• /
• 2000

In this study, we have investigated the holography recording and reconstruction of the polarization state in chalcogenide $A_{s40}Ge_{10}Se_{15}S_{35}4 thin films using a He-Ne laser light(633nm). The thickness of thin films is a 8677${\AA}$ and 9093${\AA}$. A He-Ne laser used to probe and record of the grating. Also the polarization state of object beam modulated with a $\lambda/4$ wave plate. The polarization state of the +lst order diffracted beam generated by readout of the grating with a linearly polarized reference beam. It was the same-handed polarization state as the polarization state of the recording beam. The diffraction efficiency of circularly polarized recording represented higher than other polarization state.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.820-823
• /
• 2000

In this study, we have investigated the holography recording and reconstruction of the polarization state in chalcogenide $As_{40}$$Ge_{10}$$Se_{15}$$S_{35}$ thin films using a He-Ne laser light(633nm). The thickness of thin films is a 8677${\AA}$ and 9093${\AA}$. A He-Ne laser used to probe and record of the grating. Also the, polarization state of object beam modulated with a $\lambda/4$ wave plate. The polarization state of the +1st order diffracted beam generated by readout of the grating with a linearly polarized reference beam. It was the same-handed polarization state as the polarization state of the recording beam. The diffraction efficiency of circularly polarized recording represented higher than other polarization state.

• Archives of Plastic Surgery
• /
• 제46권4호
• /
• pp.375-380
• /
• 2019

Breast tissue expanders (TEs) with magnetic infusion ports are labeled "MR Unsafe." Therefore, patients with these implants are typically prevented from undergoing magnetic resonance imaging (MRI). We report a patient with a total submuscular breast TE who inadvertently underwent an MRI exam. She subsequently developed expander exposure, requiring explantation and autologous reconstruction. The safety profile of TEs with magnetic ports and the use of MRI in patients with these implants is surprisingly controversial. Therefore, we present our case report, a systematic literature review, and propose procedural guidelines to help ensure the safety of patients with TEs with magnetic ports that need to undergo MRI exams.