The 3-D Computer

The 3-D Computer [1]–[4] is a unique implementation of a cellular array processor. We have developed two radically new technologies which enable massive numbers of communication channels both between silicon wafers and through them. A parallel processor (single instruction-multiple data stream cellular array processor) has been designed and built to demonstrate the potential of this technological approach. While the 3-D Computer which has been built and operated in a small scale implementation relative to the long-term aims of this technology, it is nevertheless an extremely powerful computer. The current feasibility demonstration 3-D Computer is a 32×32 array of processors partitioned over five wafers stacked one on top of another. The throughput of this current machine is >600 million operations per second (MOPS) with a 10 MHz clock, while the projected throughput of a full scale machine is >100 billion operations per second (BOPS), again with a 10 MHz clock. The extension of the level of circuit integration beyond that of VLSI and WSI, which is made possible by the 3-D technologies of wafer feedthroughs and microbridges, enable us to achieve these enormous throughputs in a very compact form and at very low power. The small size and low power attributes of the 3-D Computer result from the elimination of the chip level and board level packaging and the intraboard wiring required by conventional levels of circuit integration.     

三维计算机视觉的进展

三维计算机视觉包括距离数据的采集,三-维特征提取,物体建模与匹配等问题。本文就以上诸方面对三维计算机视觉的研究进展进行评述,并给出若干今后研究的建议。     

Computer Vision for a 3-D Visualisation and Telepresence Collaborative Working Environment

An integrated media system is a computer-based environment that supports the creation, sharing, distribution and effective communication of multimodal information across the boundaries of space and time. The EU Information Societies Technology (IST) project — VIRTUE (Virtual Team User Environment) is working steadily towards the realisation of most aspects and properties of such a system, with particular emphasis on a three-way semi-immersive telepresence videoconferencing scenario. In contrast with the traditional videoconferencing system that we know now, the outcome of the project is expected to demonstrate distinctive presence features and experience for the conference participants. These include views of full-body-size realistically rendered images, eye-to-eye contact, gaze awareness, normal hand gesturing and direct body language. The purpose of this paper is to describe the current work in its related technical field, and the main objectives and scope of this project. One optional software system framework is outlined, and also illustrated are some component technologies in 3-D computer vision analysis that are being developed. The application of these component technologies, notably the dense-disparity estimation and the novel view synthesis, in 3-D interactive video manipulation and visualisation, are widely expected.     

3-D计算机视觉系统的高精度摄象机定标算法—DLTEAⅡ

本文在分析计算机视觉系统中摄象机几何模型的基础上,修正了光学镜头畸变模型使之与数字成象系统相配合,提出了一个非常适合于3—D计算机视觉系统的通用高精度摄象机定标方法:增强型直接线性变换—误差拟合算法(DLTEAⅡ).实验表明,使用普通CCD摄象机的立体视觉系统经DLTEAⅡ定标后,在300mm×200mm视场和0.8m～0.9m深度范围内其三维定位的绝对精度分别为dx<0.03mm,dy<0.04mm和dz<0.09mm,相对精度为视场大小和深度的1/10000.本文所提出的定标方法在三维计算机视觉、智能机器人、工业自动化生产、近景摄影测量和军事等领域有着广泛的应用前景.     

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.     

3-D MCM的种类

介绍了3-D MCM封装的种类,其中包括芯片垂直互连和2-D MCM的垂直互连。芯片的垂直互连,包括芯片之间通过周边进行互连,以及芯片之间通过贯穿芯片进行垂直互连(面互连);2-D MCM模块垂直互连,包括2-D MCM之间通过周边进行互连,以及面互连的模式。     

High-Performance Active Liquid Crystalline Shutters for Stereo Computer Graphics and Other 3-D Technologies

Stereoscopic computer displays create a 3-D image by alternating two separate images for each of the viewer's eyes. Field-sequential viewing systems supply each eye with the appropriate image by blocking the wrong image for the wrong eye. In our work, we have developed a new mode of operation of a liquid crystal shutter that provides for highly effective blockage of undesired images when the screen is viewed in all viewing directions and eliminates color shifts associated with long turn-off times. The goal was achieved by using a pi-cell filled with low-rotational-viscosity and high-birefringence fluid and additional negative birefringence films with splay optic axis distribution. The shutter demonstrates a contrast ratio higher than 800:1 for head-on viewing and 10:1 in the viewing cone of about 45deg. The relaxation time of the shutter does not exceed 2 ms and is the same for all three primary colors     

Reconstruction of 3-D horizons from 3-D seismic datasets

We propose a method for extracting automatically and simultaneously the quasi-horizontal surfaces in three-dimensional (3-D) seismic data. The proposed algorithm identifies connected sets of points which form surfaces in 3-D space. To improve reliability, this algorithm takes into consideration the relative positions of all horizons, and uses globally self-consistent connectivity criteria which respect the temporal order of horizon creation. The first stage of the algorithm consists of the preliminary estimation of the local direction of each horizon at each point of the 3-D space. The second stage consists of smoothing the signal along the detected layer structure to reduce noise. The last stage consists of the simultaneous building of all 3-D horizons. The output of the processing is a set of 3-D horizons represented by a series of triangulated surfaces.     

3-D object recognition using 2-D views

We consider the problem of recognizing 3-D objects from 2-D images using geometric models and assuming different viewing angles and positions. Our goal is to recognize and localize instances of specific objects (i.e., model-based) in a scene. This is in contrast to category-based object recognition methods where the goal is to search for instances of objects that belong to a certain visual category (e.g., faces or cars). The key contribution of our work is improving 3-D object recognition by integrating Algebraic Functions of Views (AFoVs), a powerful framework for predicting the geometric appearance of an object due to viewpoint changes, with indexing and learning. During training, we compute the space of views that groups of object features can produce under the assumption of 3-D linear transformations, by combining a small number of reference views that contain the object features using AFoVs. Unrealistic views (e.g., due to the assumption of 3-D linear transformations) are eliminated by imposing a pair of rigidity constraints based on knowledge of the transformation between the reference views of the object. To represent the space of views that an object can produce compactly while allowing efficient hypothesis generation during recognition, we propose combining indexing with learning in two stages. In the first stage, we sample the space of views of an object sparsely and represent information about the samples using indexing. In the second stage, we build probabilistic models of shape appearance by sampling the space of views of the object densely and learning the manifold formed by the samples. Learning employs the Expectation-Maximization (EM) algorithm and takes place in a "universal," lower-dimensional, space computed through Random Projection (RP). During recognition, we extract groups of point features from the scene and we use indexing to retrieve the most feasible model groups that might have produced them (i.e., hypothesis generation). The likelihood of each hypothesis is then computed using the probabilistic models of shape appearance. Only hypotheses ranked high enough are considered for further verification with the most likely hypotheses verified first. The proposed approach has been evaluated using both artificial and real data, illustrating promising performance. We also present preliminary results illustrating extensions of the AFoVs framework to predict the intensity appearance of an object. In this context, we have built a hybrid recognition framework that exploits geometric knowledge to hypothesize the location of an object in the scene and both geometrical and intesnity information to verify the hypotheses.     

3-D vector radix algorithm for the 3-D new Mersenne numbertransform

Three-dimensional convolutions and correlations are used for three-dimensional image-processing applications. Their calculation involves extensive computation, which makes the use of fast transforms very advantageous. As the number of arithmetic operations is very large, the accumulation of rounding or truncation errors arising in the use of the fast Fourier and Hartley transforms tends to increase. Number theoretic transforms are calculated modulo an integer and hence they are not subject to these errors. Previously, a one-dimensional transform called the new Mersenne number transform (NMNT) was introduced and applied successfully to the calculation of 1-D convolutions/correlations. Unlike other Mersenne number transforms, the NMNT can handle long data sequences and has fast algorithms. In the paper, the 1-D definitions are first extended to the 3-D case in detail for use in 3-D image processing applications. The concept and derivation of the 3-D vector radix algorithm is then introduced for the fast calculation of the 3-D NMNT. The proposed algorithm is found to offer substantial savings over the row-column approach in terms of arithmetic operations. Examples are given showing the validity of both transform and algorithm     

未来的IC向垂直发展

几十年来,半导体制造商年复一年地缩小IC的晶体管尺寸,以达到摩尔定律所描述的不断增加的速度和性能,亦即约18个月芯片性能要翻一番.摩尔定律只有在电路的RC延时与信号传输延时相比可以忽略时成立.然而,对于亚微米来说,RC延时变为主要因素.曾经寄希望于改用铜金属化、低K介电质和化学机械抛光(CMP)来降低RC延时,以及缩小尺寸来达到由摩尔定律预期的未来十年的性能改进.     

光学三维传感

介绍了光学三维传感的几种主要的方法,例如:传播时间法、光学三角测量法、光栅投影法等,并且对它们作了比较和总结.这可以作为今后正确和广泛应用三维传感技术的参考.     

相移等力线法用于三维应力场非破坏检测

给出了三幅图像相移法实现散光等力线条纹自动分析的原理，论述了相移等力线方法用于三维应力场非破坏测量技术。对复合胶接结构界面三维应力问题进行了实验研究。实验表明，此方法可以精确、无损、快速得到所测结构的应力分量。     

3-DMCM实用化的进展

介绍了 3- D MCM的四种封装模式的应用实例 ,详细讨论了各种模式的工艺 ,优点及存在的问题。 3-D MCM是未来微电子封装的发展趋势。     

CPML在3维HIFFDTD算法中的实现

文中将CPML引入3维弱无条件稳定算法HIE-FDTD中,详细推到了CPML在3维弱无条件稳定HIE-FDTD中的差分公式.为了验证CPML在3维HIE-FDTD中的吸波性能,建立了数值计算模型,并将CPML的吸波性能同其它几种常用的吸收边界条件进行了比较.结果显示,当将CPML层数设置为8时,其最大反射误差为-72 dB,远低于传统FDTD方法的反射误差.另外,当匹配层参数设置为α=0.05,可以在一个较大范围内选取κmax和σmax来实现最佳误差,从而使得在选值时易于预测反射情况.     

3-D segmentation of MR images of the head for 3-D display

Algorithms for 3-D segmentation and reconstruction of anatomical surfaces from magnetic resonance imaging (MRI) data are presented. The 3-D extension of the Marr-Hildreth operator is described, and it is shown that its zero crossings are related to anatomical surfaces. For an improved surface definition, morphological filters-dilation and erosion-are applied. From these contours, 3-D reconstructions of skin, bone, brain, and the ventricular system can be generated. Results obtained with different segmentation parameters and surface rendering methods are presented. The fidelity of the generated images comes close to anatomical reality. It is noted that both the convolution and the morphological filtering are computationally expensive, and thus take a long time on a general-purpose computer. Another problem is assigning labels to the constituents of the head; in the current implementation, this is done interactively.     

Anisotropic 2-D and 3-D averaging of fMRI signals

A novel method for denoising functional magnetic resonance imaging temporal signals is presented in this note. The method is based on progressively enhancing the temporal signal by means of adaptive anisotropic spatial averaging. This average is based on a new metric for comparing temporal signals corresponding to active fMRI regions. Examples are presented both for simulated and real two and three-dimensional data. The software implementing the proposed technique is publicly available for the research community.     

三维显示技术的探索

我们绝大多数人所看到的世界都是三维的,而所触及的几乎所有介质,无论是印刷的、照片或影像,都是二维的.     

Monolithic 3-D silicon photonics

A monolithic CMOS compatible process has been developed to realize vertically integrated devices in silicon. The method involves the implantation of an oxygen into a patterned silicon substrate to form buried guiding structures. These buried devices are separated from a surface silicon layer by an intervening layer of silicon dioxide formed through the implantation process. Photolithography and etching is used to define devices on the surface silicon layer. The method has been utilized to realize the vertically coupled microdisk resonators and a variety of microresonator-based integrated optical elements. A new method for extraction of the unloaded Q of a cavity from its measured spectrum is also described.