激光三维成像技术及其主要应用

阐述了目前三维成像在其常见应用领域中的研究,主要致力于研究高分辨率三维成像系统。三维激光成像是一项可以应用于探测隐藏目标、地形测绘、构建虚拟环境、城市建模、目标识别等领域中的技术。在区域成像技术中,除了如立体视觉和结构化灯光等更常规的技术,实时三维传感也具有现实可操作性。当前三维激光成像技术已经发展到有能力提供厘米级波长的高分辨率三维成像,这将给许多领域提供方便,包括法律的实施和法医调查。与CCD和红外技术等传统的被动成像系统相比,激光成像技术不仅能提供强度和范围信息,还能穿透植被和窗户等特定情景元素。这意味着激光三维成像系统在目标识别与辨认等方面具备新的潜力。结果表明,激光三维成像系统可以在许多情况下得到应用。     

Submicron super TFTs for 3-D VLSI applications

High performance submicron super TFTs are reported. A novel grain enhancement method is used to form large single grain silicon at the channel region of the TFT, making its structure comparable to SOI MOSFET. The process can be performed with high controllability, thus giving much smaller device-to-device variation compared to conventional TFT process. The reported n-channel super TFT displays a subthreshold swing of 72 mV/dec, g_max=198 mS/mm and an I_dast of 0.3 mA/μm at V_g-V_t=1.5 V, with L_G=0.4 μm and t_ox=110 Å. The super TFT technology will facilitate the formation of three-dimensional (3-D) VLSI circuits and double gate CMOS     

A generalization of the octonion Fourier transform to 3-D octonion-valued signals: properties and possible applications to 3-D LTI partial differential systems

Multidimensional Systems and Signal Processing - The paper is devoted to the development of the octonion Fourier transform (OFT) theory initiated in 2011 in articles by Hahn and Snopek. It is also...     

3-D double-directional radio channel characterization for urban macrocellular applications

We measured the spatial properties of the three-dimensional (3D) double-directional radio channel in urban macrocell environments separately at both ends of the link. In this paper, we study propagation conditions pertaining to reception and transmission at the mobile terminal, measured using a wideband channel sounder and a dual-polarized spherical antenna array. We were able to refine the results of the measurements conducted at the base station, and extend the study to full double-directional 3D channels. Individual propagation paths could be identified precisely, in some cases even considerable scattering from lampposts was observed. Our results show that over-rooftop-dominated propagation often occurs via building roofs with LOS to the base station antenna, acting as strong secondary signal sources. Based on measurements along continuous routes we demonstrate that the dominant propagation mechanisms can vary considerably when the mobile moves in the environment. We also present typical directional properties of the 3D radio channel at the mobile terminal in urban macrocell environments characterized by street canyons, showing how the angular distribution of energy is correlated with the excess delay.     

Design of high-Q 3-D integrated inductors for high frequency applications

Design of 3-Dimensional micromachined inductors on high-(10 KΩ·cm) and low-resistivity(10 Ω·cm) Si substrate fabricated using stress metal technology we have developed [1, 2] is presented. Using high frequency electromagnetic simulation of 3-Dimensional inductors performed by Ansoft HFSS®, we have investigated the effects of number of turns, effective radius, metal line width, and different substrates on the quality factor, Q and self-resonant frequency, f _sr of these inductors. We also have compared the simulated results with the measurement results of 3-D inductors fabricated using this technology.     

An SoC with 1.3 gtexels/s 3-D graphics full pipeline for consumer applications

A high-speed three-dimensional (3-D) graphics SoC for consumer applications is presented. A 166-MHz 3-D graphics full pipeline engine with performance of 33 Mvertices/s and 1.3Gtexels/s, and 333-MHz ARM11 RISC processor, and video composition IPs are integrated together on a single chip. The geometry part of 3-D graphics IP provides full programmability in vertex and triangle level, and two-level multi-texturing with trilinear MIPMAP filtering are realized in the rasterization part. Per-pixel effects such as fog effects, alpha blending, and stencil test are also implemented in the proposed 3-D graphics IP. The rasterization architecture is designed for reducing external memory accesses to achieve the peak performance. The chip is fabricated using 0.13/spl mu/m CMOS technology and its area is 7.1/spl times/7.0mm/sup 2/.     

How to reduce 3-D gray-scale mathematical morphology to 2-D

A planar encoding of three-dimensional (3-D) images, which is commutative with respect to set and gray-scale morphological operations, is proposed. Such an encoding indicates a way to reduce 3-D set and mathematical morphology operations to two-dimensional (2-D) ones     

MOS Integrated circuits fabricated on multilayer heteroepitaxial silicon-insulator structures for applications to 3-D integrated circuits

Multiple layers of single-crystal silicon and boron phosphide have been grown on silicon and silicon-on-sapphire substrates. Up to four layers have been grown on silicon and two layers on silicon-on-sapphire. The quality of the silicon layers was confirmed by fabricating PMOS integrated circuits on the top silicon layer in all of these structures. The integrated circuits contained individual transistors, p-n diodes, inverters, flip-flops, and ring oscillators. All circuits successfully operated on all of the layers tested. The transistor mobilities tended to drop as more layers were added to the structure. The delay time of the ring oscillators rose as the number of layers increased reflecting the drop in transistor mobilities. By fabricating circuits on the various layers, the quality of the individual layers has been shown to be sufficiently high to consider this material combination as a possible candidate for 3-D integrated circuits. The boron phosphide was used not only as an insulator but also for the fabrication of vertical resistors and p-n junctions.     

Conformal absorbing boundary conditions for 3-D problems:derivation and applications

Vector absorbing boundary conditions (ABCs) for doubly curved surfaces are presented, and their applicability to finite elements for scattering calculations are discussed. A performance study of these ABCs is carried out in terms of accuracy and computational requirement, and scattering patterns for several targets are included for validation purposes. It is found that accurate far-field results can be obtained by terminating the finite element mesh a fraction of a wavelength from the scattering structure     

Global-motion estimation in image sequences of 3-D scenes for coding applications

A technique for global-motion estimation and compensation in image sequences of 3-D scenes is described in this paper. Each frame is segmented into regions whose motion can be described by a single set of parameters and a set of motion parameters is estimated for each segment. This is done using an iterative block-based image segmentation combined with the estimation of the parameters describing the global motion of each segment. The segmentation is done using a Gibbs-Markov model-based iterative technique for finding a local optimum solution to a maximum a posteriori probability (MAP) segmentation problem. The initial condition for this process is obtained by applying a Hough transform to the motion vectors of each block in the frame obtained by block matching. In each iteration, given a segmentation, the motion parameters are estimated using the least-squares (LS) technique. To obtain the final segmentation and the more appropriate higher-order motion model for each segment, a final stage of splitting/merging of segments is needed. This step is performed on the basis of maximum-likelihood decisions combined with the determination of the higher-order model parameters by LS. The incorporation of the proposed global-motion estimation technique in an image-sequence coder was found to bring about a substantial reduction in bit-rate without degrading the perceived quality or the PSNR.     

Edge-based 3-D camera motion estimation with application to videocoding

Two classes of algorithms for modeling camera motion in video sequences captured by a camera are proposed. The first class can be applied when there is no camera translation and the motion of the camera can be adequately modeled by zoom, pan, and rotation parameters. The second class is more general in that it can be applied when the camera is undergoing a translation motion, as well as a rotation and zoom and pan. This class uses seven parameters to describe the motion of the camera and requires the depth map to be known at the receiver. The salient feature of both algorithms is that the camera motion is estimated using binary matching of the edges in successive frames. The rate distortion characteristics of the algorithms are compared with that of the block matching algorithm and show that the former provide performance characteristics similar to those of the latter with reduced computational complexity.     

3-D/2-D registration by integrating 2-D information in 3-D

In image-guided therapy, high-quality preoperative images serve for planning and simulation, and intraoperatively as "background", onto which models of surgical instruments or radiation beams are projected. The link between a preoperative image and intraoperative physical space of the patient is established by image-to-patient registration. In this paper, we present a novel 3-D/2-D registration method. First, a 3-D image is reconstructed from a few 2-D X-ray images and next, the preoperative 3-D image is brought into the best possible spatial correspondence with the reconstructed image by optimizing a similarity measure (SM). Because the quality of the reconstructed image is generally low, we introduce a novel SM, which is able to cope with low image quality as well as with different imaging modalities. The novel 3-D/2-D registration method has been evaluated and compared to the gradient-based method (GBM) using standardized evaluation methodology and publicly available 3-D computed tomography (CT), 3-D rotational X-ray (3DRX), and magnetic resonance (MR) and 2-D X-ray images of two spine phantoms, for which gold standard registrations were known. For each of the 3DRX, CT, or MR images and each set of X-ray images, 1600 registrations were performed from starting positions, defined as the mean target registration error (mTRE), randomly generated and uniformly distributed in the interval of 0-20 mm around the gold standard. The capture range was defined as the distance from gold standard for which the final TRE was less than 2 mm in at least 95% of all cases. In terms of success rate, as the function of initial misalignment and capture range the proposed method outperformed the GBM. TREs of the novel method and the GBM were approximately the same. For the registration of 3DRX and CT images to X-ray images as few as 2-3 X-ray views were sufficient to obtain approximately 0.4 mm TREs, 7-9 mm capture range, and 80%-90% of successful registrations. To obtain similar results for MR to X-ray registrations, an image, reconstructed from at least 11 X-ray images was required. Reconstructions from more than 11 images had no effect on the registration results.     

Geodesic流多伯努利检测前跟踪方法

由于粒子退化,基于粒子滤波的多伯努利检测前跟踪滤波器对多目标后验密度的估计不准确,导致量测非相参积累的效果不理想.为此,将Geodesic粒子流引入多伯努利检测前跟踪算法,以提升后验密度估计的准确度.此外,合并航迹时利用目标的航向信息,从而降低航迹交叉时不同目标的航迹被错误合并的概率.通过Rayleigh杂波中Swerling 1型起伏目标的检测及跟踪结果证明了所提算法的性能.     

An order-recursive algorithm to solve the 3-D Yule-Walker equationsof causal 3-D AR models

An order-recursive algorithm is proposed to solve the 3-D Yule-Walker equations of causal 3-D AR models. It is computationally efficient and can be easily transformed into a computer program. Moreover, it can be utilized to determine the orders of a causal 3-D AR process     

Response of realistic soil for GPR applications with 2-D FDTD

The three-dimensional (3D), wideband, bistatic ground penetrating radar (GPR) scatter response of rough, realistic ground is efficiently and accurately simulated using a hybrid high resolution 3D and large area two-dimensional (2D) finite difference time domain (FDTD) model. The 3D computation carefully models the transmitting and receiving antennas, while the 2D FDTD models wave propagation between the antennas and the scattering by the soil below them. The FDTD soil model considers realistic frequency dependent (dispersive) soil with Gaussian height variations. The modeling results are compared to experiments performed with the Geo-Centers, Inc., Newton, MA, commercially available GPR system used for mine detection. Despite the simplicity of the 2D model, the results of the simulation and the experiment agree quite well     

Finite-element method modeling of superconductors: from 2-D to 3-D

A three-dimensional (3-D) numerical modeling technique for solving problems involving superconducting materials is presented. The model is implemented in finite-element method software and is based on a recently developed 3-D formulation for general electromagnetic problems with solid conductors. It has been adapted for modeling of superconductors with nonlinear resistivity in 3-D, characterized by a power-law E-J relation. It has first been compared with an existing and verified two-dimensional (2-D) model: Compared are the current density distribution inside the conductors and the self-field ac losses for different applied transport currents. Second, the model has been tested for computing the current distribution with typical 3-D geometries, such as corner-shaped and twisted superconductors. Finally, it has been used with two superconducting filaments in the presence of external magnetic field for verifying the existence of coupling currents. This effect deals with the finite length of the conductors and cannot be taken into account by 2-D models.     

Spatiotemporal selective extrapolation for 3-D signals and its applications in video communications.

In this paper, we derive a spatiotemporal extrapolation method for 3-D discrete signals. Extending a discrete signal beyond a limited number of known samples is commonly referred to as discrete signal extrapolation. Extrapolation problems arise in many applications in video communications. Transmission errors in video communications may cause data losses which are concealed by extrapolating the surrounding video signal into the missing area. The same principle is applied for TV logo removal. Prediction in hybrid video coding is also interpreted as an extrapolation problem. Conventionally, the unknown areas in the video sequence are estimated from either the spatial or temporal surrounding. Our approach considers the spatiotemporal signal including the missing area in a volume and replaces the unknown samples by extrapolating the surrounding signal from spatial, as well as temporal direction. By exploiting spatial and temporal correlations at the same time, it is possible to inherently compensate motion. Deviations in luminance occurring from frame to frame can be compensated, too.     

A new modeling technique for simulating 3-D arbitrary conductor-magnet structures for RFIC applications

This paper presents a new modeling technique, entitled extended MagPEEC model, which can be used to simulate arbitrary three-dimensional conductor-magnet structures of any geometry with direct conductor-magnet interfaces included. The new model was validated using a sample coaxial transmission line structure and was applied to investigate a group of super compact six-layer stacked spiral radio frequency integrated circuits (RFICs) inductor structures with various magnetic media integrated inside. This new modeling technique can be used to assist design of complex conductor-magnet structures including various magnetic-enhanced inductors for RFIC applications.