This paper is concerned with the data compression and interpolation of multi-view image set. In this paper, we propose a novel disparity compensation scheme based on geometric relationship. We first investigate the geometric relationship between a point in the object space and its projection onto view images. Then, we propose the disparity compensation scheme which utilize the geometric constraints between view images. This scheme is used to compress the multi-view image into the structure of the triangular patches and the texture data on the surface of patches. This scheme not only compresses the multi-view image but also synthesize the view images from any viewpoints in the viewing zone. Also, this scheme is fast and have compatibility with 2-D interframe coding. Finally, we report the experiment, where two sets multi-view image were used as original images and the amount of data was reduced to 1/19 and 1/20 with SNR 34 dB and 20 dB, respectively.

In this paper, we present new algorithms to calculate the reverse distance transformation and to extract the skeleton based upon the Euclidean metric for an arbitrary binary picture. The presented algorithms are applicable to an arbitrary picture in all of n-dimensional spaces (n2) and a digitized picture sampled with the different sampling interval in each coordinate axis. The reconstruction algorithm presented in this paper is resolved to serial one-dimensional operations and efficiently executed by general purpose computer. The memory requirement is very small including only one picture array and single one-dimensional work space array for n-dimensional pictures. We introduce two different definitions of skeletons, both of them allow us to reconstruct the original binary picture exactly, and present algorithms to extract those skeltons from the result of the squared Euclidean distance transformation.

In this paper we estimate the number of permutations realizable in fault-tolerant multistage interconnection networks designed to tolerate faults on any switching element. The Parallel Omega network and the INDRA network are representative types of fault-tolerate multistage interconnection networks designed to tolerate a single fault. In order to evaluate the enhancement in the function of network by preparing the hardware redundancy for fault-tolerance, we estimate the number of permutations realizable in fault-tolerant networks. This result enables us to set up a standard to evaluate the hardware redundancy required to tolerate multifaults from the viewpoint of the enhancement of network function. This paper concludes that in the case where the number of inputs is up to 32 the increase ratio of the number of realizable permutations is no more than 1/0.73 even if the tolerance to multifaults is prepared instead of the tolerance to a single fault.

Three-dimensional display technologies that require special glasses are not suitable for telecommunications because wearing glasses is inconvenient and it is defficult to observe facial expressions. Our previous 6.3-inch 3D display was inadequate for presenting images with realistic sensation. In this paper, a direct view 15-inch 3D display is described. The display is made up of a l5-inch TFT LCD and a composite lenticular sheet (LS), and uses the head tracking technique. Quantitative evaluation of the stereoscopic sensation of the display was studied using the 3D display, and better stereoscopic sensation values were obtained compared with a 2D display mode, thus comfirming the display's usefulness.

Gate-controlled negative differential resistance (NDR) due to interband tunneling has been observed at room temperature in a Surface Tunnel Transistor (STT). The STT consists of a highly degenerate p+-drain, an n+-doped channel with an insulated gate, and an n+-source connected to the channel. To demonstrate application as a functional device, a bistable circuit consisting of only one STT and one load resistor was organized and its operation was confirmed. The obtained valley current in the NDR characteristics of the STT, however, is relatively large and limits the device performance. In order to clarify the origin of the valley current, we fabricated p+-n+ tunnel diodes in which growth interruption was done at the pn junction, and investigated the dependence of the NDR characteristics on both the impurity concentration at the regrown interface and the temperature. These measurements indicate that the valley current is mainly caused by the excess tunneling current through traps formed by the residual oxygen at the regrown interface.

This paper describes small AlGaAs/GaAs HBT's for low-power and high-speed integrated circuits. The device fabrication is based on a new bridged base electrode technology that permits emitter width to be defined down to 1 µm. The new technology features oxygen-ion implantation for emitter-base junction isolation and zinc diffusion for extrinsic base formation. The oxygen-ion implanted emitter-base junction edge has been shown to provide a periphery recombination current much lower than that for the previous proton implanted edgs, the result being a much higher current gain particularly in small devices. The zinc diffusion offers high device yield and good uniformity in device characteristics even for a very thin (0.04 µm) base structure. An HBT with emitter dimensions of 12.4 µm2 yields an fT of 103 GHz and an fmax of 62 GHz, demonstrating that the new technology has a significant advantage in reducing the parasitic elements of small devices. Fabricated one-by-eight static frequency dividers and one-by-four/one-by-five two-modulus prescalers operate at frequencies over 10 GHz. The emitters of HBT's used in the divider are 12.4 µm2 in size, which is the smallest ever reported for AlGaAs/GaAs HBT IC's. These results indicate that the bridged base electrode technology is promising for developing a variety of high-speed HBT IC's.

This paper proposes a new subband adaptive filtering algorithm for adaptive FIR filters. The number of taps for each subband filter is adaptively controlled based on a sum of the absolute coefficients or the coefficient power in conjunction with the subband signal power. Keeping the total number of taps constant, redundant taps are redistributed to subbands where the number of taps is insufficient. Simulation results with a white signal show that the number of taps in each subband approaches an optimum as each subband filter converges. For a colored signal, tap assignment by the new algorithm is as stable as for a white signal.

For system identification problems, such as noise and echo cancellation, FIR adaptive filters are mainly used for their simple adaptation and numerical stability. When the unknown system is a high-Q resonant system, having a very long impulse response, IIR adaptive filters are more efficient for reduction in the order of a transfer function. One way to realize the IIR adaptive filter is a separate form, in which the numerator and the denominator are separately realized and adjusted. In the actual applications, the order of the unknown system is not known. In this case, it is very important to estimate the total order and the order assignment on the numerator and the denominator. In this paper, effects of the order estimation error on the residual error are investigated. In this form, indirect error evaluation called "equation error" is used. Through theoretical and numerical investigation, the following results are obtained. First, under estimation of the order of the denominator causes large degradation. Second, over estimation can improve the performance. However, this improvement is saturated to some extent due to cancellation of the redundant poles and zeros. Third, the system identification error is proportional to the equation error as the adaptive filter approaching the optimum. Finally, there is possibility of recovering from the unstable state as the order assignment approaches to the optimum in an adaptive process using the equation error. Computer solutions are provided to aid in gaining insight of the order assignment and stability problem.

This paper describes an image synthesis method based on an estimation of camera parameters. In order to acquire high quality images using image synthesis, we take some constraints into account, which include angle of view, synchronization of change of scale and change of viewing direction. The proposed method is based on an investigation that any camera operation containing a change of scale and a pure 3D rotation can be represented by a 2D geometric transformation. The transformation can explain all the synthesis procedure consisting of locating, synchronizing, and operating images. The procedure is described based on a virtual camera which is constituted of a virtual viewing point and a virtual image plain. The method can be efficiently implemented in such a way that each image to be synthesized undergoes the transformation only one time. The parameters in the image transformation are estimated from image sequence. The estimation scheme consists of first establishing correspondence and then estimating the parameters by fitting the correspondence data to the transformation model. We present experimental results and show the validity of the proposed method.

The classical supervised learning algorithms for optimizing multi-layered feedforward neural networks, such at the original back-propagation algorithm, suffer from several weaknesses. First, they have the possibility of being trapped at local minima during learning, which may lead to failure in finding the global optimal solution. Second, the convergence rate is typically too slow even if the learning can be achieved. This paper introduces a new learning algorithm which employs a genetic-type search during the learning phase of back-propagation algorithm so that the above problems can be overcome. The basic idea is to evolve the network weights in a controlled manner so as to jump to the regions of smaller mean squared error whenever the back-propagation stops at a local minimum. By this, the local minima can always be escaped and a much faster learning with global optimal solution can be achieved. A mathematical framework on the weight evolution of the new algorithm in also presented in this paper, which gives a careful analysis on the requirements of weight evolution (or perturbation) during learning in order to achieve a better error performance in the weights between different hidden layers. Simulation results on three typical problems including XOR, 3-bit parity and the counting problem are described to illustrate the fast learning behaviour and the global search capability of the new algorithm in improving the performance of back-propagated network.

Mode separation of a multiplex mode in a mode-division multiplexing system is studied. The clear, desired single-mode pattern, which is separated from the multiplex mode by using a holographic filter, is observed in the experiment.

We report the development of high-performance small-scale AlGaAs/GaAs collector-up heterojunction bipolar transistors (C-up HBT) with a carbon (C)-doped base layer. Oxygen-ion (O+) implantation is used to define their intrinsic emitter/base junctions and zinc (Zn)-diffusion is used to lower the resistivity of their O+-implanted extrinsic base layers. The highly resistive O+-implanted AlGaAs layer in the extrinsic emitter region sufficiently suppresses electron injection even under high-forward-bias conditions, allowing high collector current densities. The use of a C-doped base is especially effective for small-scale C-up HBT's because it suppresses the undesirable turn-on voltage shift caused by base dopant diffusion in the intrinsic area around the collector-mesa perimeter that occurs during the high-temperature Zn-diffusion process after implantation. Even in a small-scale trasistor with a 2 µm2 µm collector, a current gain of 15 is obtained. A microwave transistor with a 2 µm10 µm collector has a cutoff frequency fT of 68 GHz and a maximum oscillation frequency fmax of 102 GHz. A small-scale C-up HBT with a 2 µm2 µm collector shows a higher fmax of 110 GHz due to reduced base/collector capacitance CBC and its fmax remains above 100 GHz, even at a low collector current of 1 mA. The CBC of this device is estimated to be as low as 2.2 fF. Current gain dependence on collector size is also investigated for C-up HBT's and it is found that the base recombination current around the collector-mesa perimeter reduces the current gain.

To provide personal, intelligent, and multimedia services through a mobile communications network, a Mobile Service Control Point (M-SCP) was developed, which performs both the location register and service control functions. The M-SCP was constructed on a common platform to allow quick introduction of new services. Software techniques to reduce the frequency of process-switching, assign the highest priority to real-time tasks, and operate a multiple-CPU structure provide faster real-time processing. This is confirmed by computer simulation and research in the field.

This paper proposes an adaptive modulation/TDMA scheme to achieve high capacity personal multi-media communication systems. TDMA is employed to cope with various bit rate for multi-media services. The modulation scheme is selected from 1/4-rate QPSK, 1/2-rate QPSK, QPSK, 16QAM and 64QAM according to the received C/IC (power ratio of the desired signal to the co-channel interference) and the delay spread. The spectral efficiency is evaluated by using the simulated bit error rate (BER) performance as well as the cumulative distribution of the C/IC with parameters of cell configurations. The results show that the spectral efficiency of the proposed scheme is 3.5 times higher than that of the conventional QPSK systems at the outage probability of 10%, and the effect is more remarkable at lower outage probability. The results also show that the proposed adaptive modulation is effective in improving delay spread immunity.

This paper presents the M-LCELP (Multi-mode Learned Code Excited LPC) speech coder, which has been developed for the next generation half-rate digital cellular telephone systems. M-LCELP develops the following techniques to achieve high-quality synthetic speech at 4kb/s with practically reasonable computation and memory requirements: (1) Multi-mode and multi-codebook coding to improve coding efficiency, (2) Pitch lag differential coding with pitch tracking to reduce lag transmission rate, (3) A two-stage joint design regular-pulse codebook with common phase structure in voiced frames, to drastically reduce computation and memory requirements, (4) An efficient vector quantization for LSP parameters, (5) An adaptive MA type comb filter to suppress excitation signal inter-harmonic noise. The MOS subjective test results demonstrate that 4.075kb/s M-LCELP synthetic speech quality is mostly equivalent to that for a North American full-rate standard VSELP coder. M-LCELP codec requires 18 MOPS computation amount. The codec has been implemented using 2 floating-point dsp chips.

Development of a large-scale mobile communications network (IMN: Intelligent Mobile communications Network), as an infrastructure integrating multimedia functions, is indispensable for the support of future mobile communication services aiming toward "personalization," "intelligence," and "multimedia services." This paper discusses the aims of mobile communications and the outline of network technology aspects of PDC (Personal Digital Cellular) network which is currently in service. In addition, the future prospect of mobile communication technologies is discussed with special focuses on the support of universal mobility, network architecture including mobile communications platform, and multimedia technologies in the transport and access systems.

Radar signals fluctuate because of the incoherent scattering of raindrops. Dual-polarization radar estimates rainfall rates from differential reflectivity (ZDR) and horizontal reflectivity (ZH). Here, ZDR and ZH are extracted from fluctuating radar signals by averaging. Therefore, instrumentally measured ZDR and ZH always have errors, so that estimated rainfall rates also have errors. This paper evaluates rainfall rate errors caused by signal fluctuation. Computer simulation based on a physical raindrop model is used to investigate the standard deviation of rainfall rate. The simulation considers acquisition time, and uses both simultaneous and alternate sampling of horizontal and vertical polarizations for square law and logarithmic estimators at various rainfall rates and elevation angles. When measuring rainfall rates that range from 1.0 to 10.0mm/h with the alternate sampling method, using a logarithmic estimator at a relatively large elevation angle, the estimated rainfall rates have significant errors. The simultaneous sampling method is effective in reducing these errors.

ACk is the class of problems solvable by an alternating Turing machine in space O(log n) and alternation depth O(logk n) [S. A. Cook, A taxonomy of problems with fast parallel algorithms, Inform. Contr. vol. 64]. We consider a game played by two persons: each player alternately moves a marker along an edge of a given digraph, and the first palyer who cannot move loses the game. It is shown that the problem to determine whether the first player can win the game on a digraph with n nodes exactly after logk n moves is complete for ACk nuder NC1 reducibility.

An alias free parallel structure for adaptive digital filters (ADF's) is considered. The method utilizes the properties of the Frequency-Sampling Filter (FSF) banks to obtain alias free points in the frequency domain. We propose a new cost function for parallel ADF's. The limiting value analysis of system identification using proposed cost function is given in stochastic sense. It is also shown by simulation examples that we can carry out precise system identification. The cost function is defined in each bin; accordingly, it enables the parallel processing of ADF's.

This paper presents an approach for assembly plan generation from an assembly illustration. Previously, we have already proposed an approach for the assembly plan related information acquisition from an assembly illustration, in which auxiliary lines were taken as clues. However, some ambiguity remains in dynamic information such as assembly operations and their execution order. We have verified through experiments that the ambiguity could be made clear by referring to the feedback information from the completed assemblage after the assembly operations shown in the current illustration. But in fact, in an assembly illustration there are not only the figures of mechanical parts and the auxiliary lines for visualizing their assembly relations, but explanatory words and explanatory lines as well. Explanatory words can basically be classified into two categories: instructions on assembly operations and mechanical part names. The former explicitly describes dynamic information such as the details of assembly operations. The latter also implies dynamic information such as the function of a mechanical part. Explanatory lines are usually drawn for making clear the explanatory relations. Naturally we consider that to integrate the information from explanatory words with that already obtained through the extraction of auxiliary lines will probably enable us to generate an unambiguous assembly plan from the currently observing illustration.