The transmission and processing of multimedia information requires a high-speed communications network infrastructure. This is especially true for the networks between the user's computer and the information highway. An Ethernet LAN is widely used for these networks, but it has limited throughput. Asynchronous Transfer Mode (ATM) LAN technology is a promising approach to overcome this limitation. We have developed a chip set which can be used to connect personal computers (PCs) and workstations (WSs) to a 156-Mbps ATM LAN. The advanced architecture, optimized performance and efficient buffer management enables a sustained more than 100 Mbps transfer speed to be obtained. The chip set is implemented in a 0.8 µm triple metal-layer CMOS process to integrate total 460 K transistors and consumes total 4 W at 5 V.

In order to evaluate quantitatively TMJ sound, TMJ sound in normal subject group, CMD patient group A with palpable sounds unknown to them, CMD patient group B with palpable sounds known to them, and CMD patient group C with audible sounds were detected by a contact microphone, and frequency analysis of the power spectra was performed. The power spectra of TMJ sound of normal subject group and patient group A showed patterns with frequency values below 100 Hz, whereas the power spectra of patient groups B and C showed distinctively different patterns with peaks of frequency component exceeding 100 Hz. As regards the cumulative frequency value, the patterns for each group clearly differed from those of other groups; in particular the 80% cumulative frequency value showed the greatest difference. From these results, it is assumed that the 80% cumulative frequency value can be used as an effective indicator for quantitative evaluation of TMJ sound.

In this paper we propose a new method for removing the characteristic of the piezoelectric transducer from the received signal in the pulse-echo method so that the time resolution in the determination of transit time of ultrasound in a thin layer is increased. The total characteristic of the pulse-echo system is described by cascade of distributed-constant systems for the ultrasonic transducer, matching layer, and acoustic medium. The input impedance is estimated by the inverse matrix of the cascade system and the voltage signal at the electrical port. From the inverse Fourier transform of input impedance, the transit time in a thin layer object is accurately determined with high time resolution. The principle of the method is confirmed by simulation experiments.

The Bidirectional Reflectance Distribution Function (BRDF) is an intrinsic measurement of directional properties of the earth's surface. However, the estimation of the BRDF requires many remote sensing measurements of a given surface target from different viewing angles. In addition, a good atmospheric correction scheme is a prerequisite for such an attempt. The airborne POLDER sensor measures successively reflected radiation by terrestrial surfaces in a framed image form at different viewing angles during a single airplane pass, like taking snap-shot pictures. A specially improved atmospheric correction algorithm which is applicable to a framed image data by POLDER sensor is presented. The observed reflectance images taken successively by the airborne POLDER at slightly different viewing angles are converted to a series of surface albedo images by applying our atmospheric correction algorithm. Then, the BRDFs for three surface covers, namely, "River Water," "Forest," and "Rice Field," are estimated by using successive albedo images. It is found that the BRDF for "River Water" follows Lambert law at both 550nm and 850nm. It is also found that the BRDFs for "Forest" and "Rice Field" follow Lambert's law at 550nm, but they follow an anisotropic reflection law at 850nm and fitting parameters for their BRDFs are presented.

This paper proposes a robust method for detecting step and ramp edges. In this method, an edge is defined not as a point where there is a large change in intensity, but as a region boundary based on the separability of image features which can be calculated by linear discriminant analysis. Based on this definition of an edge, its intensity can be obtained from the separability, which depends only on the shape of an edge. This characteristic enables easy selection of the optimum threshold value for the extraction of an edge, and this method can be applied to color and texture edge extraction. Experimental results have demonstrated that this proposed method is robust to noise and dulled edges, and, in addition, allows easy selection of the optimum threshold value.

In arithmetic units multiplication is a very important operation. It is a common approach to use the modified Booth's algorithm to reduce the number of partial products in a multiplication and speed it up. In this letter we show two circuits that fuse the usually separate functions of generating the partial products and selecting them. The circuits designed in DPL (Double Pass-transistor Logic) are bigger in MOS transistors, but are faster and, function at higher frequencies than a typical CMOS implementation. One of our circuits also has lower power consumption.

This paper presents a new internal image representation, in which the scene is encoded into a three-intensity-level image. This representation is generated by Laplacian-Gaussian filtering followed by dual-thresholding. We refer to this imege as three-level broad-edge representation. It supresses the high frequency noise and shading in the image and encodes the sign of relative intensity of a pixel compared with surrounding region. Image model search based on cross correlation using this representation is as reliable as the one based on gray normalized correlation, while it reduces the computational cost by 50 times. We examined the reliability and realtime performance of this method when it is applied to an industrial object recognition task. Our prototype system achieves 3232 image model search from the 128128 pixel area in 2 milli-seconds with a 9 MHz pixel clock image processor. This speed is fast enough for searching and tracking a single object at video frame rate.

This paper proposes a new method that can robustly recover 3D structure and 3D motion of 3D moving objects from a few multi-views. It recovers 3D feature points by obtaining intersections of back-projection lines which are connected from the camera's optical centers thorough projected feature points on the image planes corresponding to the different cameras. We show that our method needs only six views to suppress false 3D feature points in most cases by discussing the relation between the occurrence probability of false 3D feature points and the number of views. This discussion gives us a criterion to design the optimal multi-camera system for recovering 3D structure and 3D motion of 3D moving objects. An experimental multi-camera system is constructed to confirm the validity of our method. This system can take images from six different views at once and record motion image sequence from each view over a period of a few seconds. It is tested successfully on recovering the 3D structure of Vinus's plaster head and on recovering the 3D structure and 3D motion of a moving hand.

We have developed a neutron imaging system based on the penumbral imaging technique. The system consists of a penumbral aperture and a sensitive neutron detector. The aperture was made from a thick (6 cm) tungsten block with a toroidal taper. It can effectively block 14-MeV neutrons and provide a satisfactory sharp, isoplanatic (space-invariant) point spread function (PSF). A two-dimensional scintillator array, which is coupled with a gated two-stage image intensifier system and a CCD camera, was used as a sensitive neutron detector. It can record the neutron image with high sensitivity and high signal-to-noise ratio. The reconstruction was performed with a Wiener filter. The spatial resolution of the reconstructed neutron image was estimated to be 31 µm by computer simulation. Experimental demonstration has been achieved by imaging 14-MeV deuterium-tritium neutrons emitted from a laser-imploded target.

In identification of a finite impulse response (FIR) model using noise-corrupted input and output data, the least squares type of estimation schemes such as the ordinary least squares (LS), the corrected least squares (CLS) and the total least squares (TLS) method become often numerically unstable, when the true input signal to the system is strongly correlated. To overcome this ill-conditioned problem, we propose a regularized CLS estimation method by introducing multiple regularization parameters to minimize the mean squares error (MSE) of the regularized CLS estimate of the FIR model. The asymptotic MSE can be evaluated by considering the third and fourth order cross moments of the input and output measurement noises, and an analytical expression of the optimal regularization parameters minimizing the MSE is also clarified. Furthermore, an effective regularization algorithm is given by using the only accessible input-output data without using any true unknown parameters. The effectiveness of the proposed data-based regularization algorithm is demonstrated and compared with the ordinary LS, CLS and TLS estimates through numerical examples.

A new high performance digital signal processor (DSP) that lowers power consumption, reduces chip count, and enables system cost savings for wireless communications applications was developed. The new device contains high performance, hard-wired functionality with a specialized instruction set to effectively implement the worldwide digital cellular standard algorithms, including GSM, PDC and NADC, and also features both full rate and future half rate processing by software modules. The device provides a wider operating voltage ranging from 1.5 V to 5.5 V using 5 V process based on the market requirement of 5 V supply voltage, even though a power supply voltage in most applications will be shifted to 3 V. Several circuits was newly developed to achieve low power consumption and high speed operation at both 5 V and 3 V process using the same data base. The device also features over 50 MIPS of processing power with low power consumption and 100 nA stand-by current at either 3 V or 5 V. One remarkable advantage is a flexible CPU core approach for the future spin-off devices with different ROM/RAM configurations and peripheral modules without requiring any CPU design changes. This paper describes the architecture of a lower power and high speed design with effective hardware and software modules implementations.

CAMs (Content Addressable Memories) are functional memories which have functions such as word-parallel equivalence search, bilateral 1-bit data shifting between consecutive words, and word-parallel writing. Since CAMs can be integrated because of their regular structure, massively parallel CAM functions can be executed. Taking advantage of CAMs, Ishiura and Yajima have proposed a parallel fault simulation algorithm using a CAM. This algorithm, however, requires a large amount of CAM storage to simulate large-scale circuits. In this paper, we propose a new massively parallel fault simulation algorithm requiring less CAM storage, and compare it with Ishiura and Yajima's algorithm. Experimental results of the algorithm on CHARGE --the CAM-based hardware engine developed in our laboratory--are also reported.

A non-invasive method is proposed to estimate the location of intracranial vascular disease using several sensors placed on the forehead. The advantage of this method over earlier measurements with a single ocular sensor is the abilty to localize the region of abnormal vascular tissue. A weighted least mean square procedure is applied to estimating the time difference between the sensor outputs using the phase distribution in the cross-spectrum. It is possible to estimate time differences shorter than sampling period. Computer simulation and clinical experiments demonstrate that a distance difference of around 20 times shorter than the wavelength can be obtained.

An analytical framework to study the nonuniformity in geographical distribution of the traffic load in low earth orbit satellite communication systems is presented. The model is then used to evaluate the throughput performance of the system with direct-sequence packet spread-slotted ALOHA multiple-access technique. As the result, it is shown that nonuniformity in traffic makes the characteristics of the system significantly different from the results of uniform traffic case and that the performance of each user varies according to its location. Moreover, the interference reached from users of adjacent satellites is shown to be one of the main factors that limit the performance of system.

This paper presents a new method for solving the structure-from-motion problem for optical flow. The fact that the structure-from-motion problem can be simplified by using the linearization technique is well known. However, it has been pointed out that the linearization technique reduces the accuracy of the computation. In this paper, we overcome this disadvantage by correcting the linearized solution in a statistically optimal way. Computer simulation experiments show that our method yields an unbiased estimator of the motion parameters which almost attains the theoretical bound on accuracy. Our method also enables us to evaluate the reliability of the reconstructed structure in the form of the covariance matrix. Real-image experiments are conducted to demonstrate the effectiveness of our method.

This paper surveys trends in and prospects for low power LSI circuits technologies for portable terminal equipment, in which low-voltage operation of LSIs will be emphasized because this equipment will be battery-powered. Since this brings about serious operation speed degradation of LSIs, however, it will become more and more important how to operate them faster under low-supply voltage. We propose two new circuit techniques that make it possible to operate LSIs at high speed even when the supply voltage is very low (1-2 V corresponding to one or two battery cells). The new low-voltage RF LSI circuit technique, developed using silicon bipolar technology and using a novel current-folded mixer architecture for the modulator, result in a highly linear modulator that operates at 2 V. Its power consumption is less than 2/3 that of previously reported ICs. And for a low voltage baseband LSI we propose the multi-threshold CMOS (MTCMOS) technique, which uses two sets of threshold-voltage levels so that the LSI can operate at high speed when driven by a 1-V power supply. The multi-threshold CMOS architecture enabled us to create LSIs that operate faster than conventional CMOS circuits using high-threshold-voltage MOSFETs. When operating with a 1-V power supply, our LSIs are three times faster than the conventional ones.

In this paper, we present a vision system for a depalletizing robot which recognizes carton objects. The algorithm consists of the extraction of object candidates and a labeling process to determine whether or not they actually exist. We consider this labeling a combinatorial optimization of labels, we propose a new labeling method applying Genetic Algorithm (GA). GA is an effective optimization method, but it has been inapplicable to real industrial systems because of its processing time and difficulty of finding the global optimum solution. We have solved these problems by using the following guidelines for designing GA: (1) encoding high-level information to chromosomes, such as the existence of object candidates; (2) proposing effective coding method and genetic operations based on the building block hypothesis; and (3) preparing a support procedure in the vision system for compensating for the mis-recognition caused by the pseudo optimum solution in labeling. Here, the hypothesis says that a better solution can be generated by combining parts of good solutions. In our problem, it is expected that a global desirable image interpretation can be obtained by combining subimages interpreted consistently. Through real image experiments, we have proven that the reliability of the vision system we have proposed is more than 98% and the recognition speed is 5 seconds/image, which is practical enough for the real-time robot task.

UDL/I test suites and UDL/I Simulation/Synthesis Environment had been developed separately in parallel. Both were designed from syntax and semantics definition of UDL/I Language Reference Manual. Through test of the UDL/I Simulation/Synthesis Environment using the UDL/I test suites, quality of the test suites and the environment had been improved. Finally all the testing result matched with expected one. It was validated that both the test suites and the environment followed UDL/I language specification.

A real-time read/write motion picture has been demonstrated by hole-burning holography using cryogenic Eu3+: Y2SiO5 crystal. In a holographic configuration the laser frequency was continuously scanned within the 7F0-5D0 absorption line while the object was in motion. This movie has no picture frames, and therefore is temporally continuous. This feature allows realization of high-speed and high-time-resolution motion recording.

In this paper, we analyze the convergence behavior of the CMA (Constant Modulus Algorithm) adaptive array working under the steepest decent method, and investigate how to achieve the highest possible output SINR (Signal to Interference plus Noise Ratio). In multipath radio environments, CMA sometimes suppresses the desired signal (stronger one) and selects to receive the interference (the weaker one) resulting in the low output SINR. This is one of the problems met in an optimization system under a nonlinear control equation where there are two or more local minima of the cost function and the final state depends on the initial condition. The study can be done only numerically by starting from various initial values. In our analysis of the CMA adaptive array in multipath radio environments, we will assume that there are two waves which are radiated from the same source and try to find out what conditions may affect the convergence behavior. In this process, we discover the effect of the neglected factor by the previous papers and revise the initial condition to guarantee the reception of the desirable wave. In conclusion, we propose the prescription of the initial weights of the array elements as well as the choice of preferable arrays.