In this paper, we propose a new method to measure the 3D object shape without special purpose lighting based upon the Backprojection of Pixel Data.This method need not extract feature points such as edges from images at all and can measure not only the feature points but the whole object surface. It is simply done by project all pixel data back into the object space from each image. Actually, we first assign all pixel data of images into voxels in the object space, and evaluate the variance of assigned data for all voxels. This process is based on the idea that a point on the object surface gives the similar color information or gray level when it is observed from different view points. Then, two kinds of voting are executed as an enhancement process to eliminate the voxels containing the false points. We present experimental results under the circular constraint of camera movement and show the possibility of the proposed method.

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.

This paper describes a 600 mV single-chip MPEG2 video decoder, implemented in a 0.5 µm triple metal CMOS technology, which operates with a 3.3-volt power supply. To achieve low power consumption, a low power dual-port RAM has been developed utilizing a selective bit line precharge scheme to reduce bit line current which is suitable for use in the bit-slice array commonly found in parametric ASIC RAM macro modules. This architecture and a non-DC current sense amp make the RAM's read power consumption one-third of that of a conventional dual-port RAM. Various techniques such as multiple-clock architecture and a system clock independent from a display clock make a system clock frequency as low as possible. The video decoder has a syntax parser, so that it can handle the higher syntactic elements of MPEG2 bit streams without any host processor and decode the Main profile at Main level of MPEG2 bit streams.

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.

This paper discusses and evaluates an effect of cell level FEC (Forward Error Correction) capability on error-free (i.e. reliable) IP multicast service over ATM networks. In the error-free IP multicast service, every receiver is delivered IP packet from the sender synchronously. Without applying the FEC policy, the expected IP packet error/loss probability becomes large, when the number of multicast receivers is large. For example, when the cell error/loss probability of each ATM data-link segment is 10-6 and the number of receivers is 103, the IP packet error/loss probability observed at the sender is about 0.5, which means that about 50% of IP packet sent from the sender will be subject to retransmission. One possible solution would be using the intermediate multicast-TCP entities, that terminate TCP protocol, among the sender and the receivers. However, this approach requires the additional entities within the network and can not provide the ordered message delivery for a multipoint-to-multipoint communication. On the contrary, with applying the FEC policy, the expected IP packet error/loss probability is dramatically reduced. Therefore, an error-free IP multicast service can be provided with a simple architecture, even when the number of multicast receiver is large, e.g. 105. For example, when the cell error/loss probability of each ATM data-link segment is 10-6, the packet error/loss probability observed at the sender is less than 10-2 even for 106 receivers. Finally, even when the cell error/loss probability of ATM data-link segment is large, e.g. 10-3, the IP multicast service without the FEC policy can not apply even for 10 receivers. However, the IP multicast with the FEC policy can apply upto few hundred of receivers.

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.

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.

This paper describes a new, low power 16-bit Digital Signal Processor (DSP). The DSP has a double-speed MAC mechanism, an accelerator for Viterbi decoding, and a block floating section which contribute to lower power consumption. The double-speed MAC can perform two multiply and accumulate operations in one instruction cycle. Since MAC operations are so common in digital signal processing, this mechanism can reduce the average clock frequency of the DSP resulting in lower power consumption. The Viterbi accelerator and block floating circuitry also reduce the clock frequency by minimizing the number of required cycles needed to be executed. The DSP was fabricated using a 0.8 µm CMOS 2-aluminum layer process technology to integrate 644 K transistors on a 9.30 mm9.09 mm die. It can realize an 11.2 kbps VSELP speech CODEC while consuming only 70 mW at 3.5 V Vdd.

A motion compensation LSI for realtime MPEG1/H.261 video encoding has been developed. This LSI employs a compact motion estimator that consists of vector search array processors. Furthermore, an efficient motion vector search strategy that enables bidirectioanl searches with a -16.0/+15.5 pels range is adopted to maintain encoded picture quality. The adopted strategy takes two steps. The first step is the full search for 2-pel precision vectors within the range of 16 pels. A 4-to-1 sub-sampling technique with a low pass filter is employed in this step. The second step is the full search for half-pel precision vectors within a 1.0 pels search range centered on the location pointed by the best 2-pel precision vectors. This strategy is compared with the exhaustive-search strategy. It is shown that the number of operations and external memory access cycles are reduced to 1/11 and 1/2, respectively, while differences of the signal to noise ratios obtained by simulation are within 0.2 dB. Those reductions contribute to lowering power dissipation. The array processors calculate the values of distortion. They accumulate the absolute differences between current and reference data with a feedback loop to keep the number of processor elements equal to the number of pels in a row of the current block. Multiple reference data buses and a delay line in the feedback loop have been introduced for efficient calculation. In addition, cascade connection of the array processors is studied to shorten calculation periods. This LSI controls input frames reordering buffers and reference frames buffers. It generates the prediction and the prediction error blocks as well as the motion vectors. AC power of current blocks and the values of distortion are obtained for the bit rate control. This LSI is fabricated using 0.8 µm 2-level metal CMOS technology and dissipates 2.0 W from 5 V supply at 36 MHz.

This paper applied the polarimetric filtering principle to Synthetic Aperture Radar (SAR) image sets in three possible polarimetric radar channels and compared the resultant imagery. The polarimetric radar channels in consideration here are Co-Pol, Cross (X)-pol, and Matched (M)-pol channels. Each channel has its own polarimetric characteristics for imaging. Using the formulation of the contrast enhancement factors based on the Stokes vector formalism, polarimetric enhanced images for three channels are shown using NASA JPL DC-8 AIRSAR data sets (CC0045L, Bonanza Creek, AK/USA). It is shown that the optimally enhanced Co- and X-Pol channel images play a decisive role in imaging in a complex featured background.

SEASAT synthetic aperture radar (SAR) echoes from the sea show beautiful images of storms over the ocean. However, the mechanisms by which such storm images are created have not yet been revealed very well. The core of these images is usually an echo-free hole which is attributed to the damping of the radar-detectable short gravity waves by the intense rain in the storm core. The bright area surrounding the core is believed to be caused by strong winds diverging from the downdraft which is collocated with the intense rain. The outer boundary of the bright area has been found to be associated with the classical gust front. During the Tropical Ocean Global Atmosphere/Coupled Ocean-Atmosphere Response Experiment (TOGA/COARE), continuous observations of rain by shipborne radars were carried out. One image of JERS-1 SAR taken in this period contains storms that were within the observation area of a shipborne radar. The SAR image and the rain-radar image are compared. Even though the signal-to-noise ratio of the SAR image is very low, there is good correspondence between heavy rain areas and some of the dark areas in the SAR image. The boundary of a rain-induced dark area is found to correspond approximately to the radar reflectivity factor (Z-factor) of 35dBZ or 5.5mm/h of rain.

A new method is proposed for realizing a flexible change detection which is free from the limitation that multitemporal images must have the same spectral bands whose center wavelength and bandwidth are identical. As spaceborne multispectral scanners are continuously improved for performance and new scanners do not necessarily have the same spaectral bands for observation, this limitation is a serious obstacle for detecting long term temporal change. The proposed method removes this limitation by using an image normalization technique based on multiple regression analysis. The method is successfully applied to actual remotely sensed multitemporal images.

We propose a distributed operation system platform for optical cable networks. This distributed platform is an extension of the previously proposed platform for a flexible cable network operation. The concept of the unit platform has been proposed for the distributed operation system platform. By using this concept, we discuss the system upgrade including the connection to other operation systems. We use an object-oriented software technology for designing the distributed operation system platform. The prototype system has been constructed using C++ programing language and the evaluated results are shown.

This work deals with thermal-noise modeling for silicon vertical bipolar junction transistors (BJTs) and relevant integrated circuits (ICs) operating at low currents. The two-junction BJT compact model is consistently derived from the thermal-noise generalization of the Shockley semiconductor equations developed in work which treats thermal noise as the noise associated with carrier velocity fluctuations. This model describes BJT with the Itô non-linear stochastic-differential-equation (SDE) system and is suitable for large-signal large-fluctuation analysis. It is shown that thermal noise in silicon p-n-junction diode contributes to "microplasma" noise. The above model opens way for a consistent-modeling-based design/optimization of bipolar device noise performance with the help of theory of Itô's SDEs.

This paper investigates the problems which inhibits the use of today's WDM networks. These are propagation delay, packet processing overhead, bit & frame synchronization, and tuning latency. So far, these problems, especially propagation delay, have been ignored in most performance analysis papers. They have always hindered network designers, but they are magnified by the order of magnitude increase in speed of optical communications systems as compared to previous media. This paper examines the impact of the propagation delay on the performance of WDM protocols with variations in the number of channels, packet length and system size, specifically in two reservation based protocols with control channels and two pre-allocation protocols without the control channels. Also the impact of three delay factors (packet processing overhead, bit & frame synchronization and tuning latency) are studied with different propagation delay parameters. In reservation protocols, each node has one agile transmitter and two receivers; one of them is fixed and the other one is agile. The fixed receiver continuously monitors the control channel, receives all control packets, and updates their own status tables in order to track the availability of the other nodes as a target and data channels to avoid the destination collisions and the data channel collisions, respectively. In pre-allocation protocols, each node has a tunable transmitter, a fixed or slow tunable receiver, and its own home channel to receive the packets. The performance of this protocol is evaluated through the discrete-event simulation in terms of the average packet delay and network throughput.

In this paper we study the properties induced by the symmetrical properties of a system of hybridly coupled oscillators of the Rayleigh type on the bifurcations of its equilibria. We first discuss the symmetrical properties of the system. Then we classify the equilibria according to their symmetrical properties. Demonstrating the structural degeneracy of the system, we give the complete stability analysis of the equilibria.

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.

We have developed a method to automatically generate a multi-input-adder circuit for an irregular array of partial products. "FASTOOL," an FIR Filter Automatic Synthesis TOOL for an HDL design environment, is proposed for use with this method and with conventional filter coefficient design programs. Filter design from specifications to the structure of Verilog-HDL has been automated. It is possible for a system designer to quickly perform filter LSI optimization by balancing cost and performance.

The relative intensity noise (RIN) spectra of DC driven 1.3 µm distributed feedback laser diodes under the influence of external reflections are measured for various currents and reflection lengths. The effective power reflectivities are 310-4-310-3. The enhanced noise is observed when the relaxation oscillation frequency coincides with the external cavity frequency. It is also observed that the RIN spectra with the near end reflections differ from those with the far end reflections. The degradation of the RIN spectra is analyzed with the rate equations numerically. A new reflection noise model, which includes the carrier density change induced by the reflections, is introduced. The near and far end reflections are characterized well by this model. Furthermore, it is found that the reflection induced noise effect can be described well by the far end reflection noise model even when the reflection length is as short as 1 m.

Physical and optical parameters within the atmosphere-ocean system have been retrieved by a multiple scattering analysis of the reflectance and degree of linear polarization data measured by the airborne POLDER sensor in Medimar campaign in 1991. Assuming an atmosphere-ocean system with a Cox-Munk type rough sea surface model, the theoretical reflectance and -degree of linear polarization were computed by the doubling and adding method for several different models. In this study the retrieval was made by assuming a fixed refractive index of the aerosol particles, i.e., Nr=1.33-0.0i. We obtained several important results in this study as follows: 1) By comparing computed results with the observed data at 0.85m, we rejected the oceanic type aerosol model and found Junge type aerosol model with its index range of 4.0v4.5 as an appropriate model for aerosols at the observation time. 2) The reflectance data analysis in the perpendicular plane rejected an isotropic Cox-Munk model, but it indicated that an anisotropic Cox-Munk model should be used in the sea surface wind field retrieval. 3) The surface wind speed was estimated to be 10.0m/secV15.0m/sec with an best estimate of V=12.5m/sec, which agrees with the observed wind speed of V=14.4m/sec. The range of the water column reflectance was also estimated to be 0.025rwc0.045 from Medimar reflectance data at 0.45m. 4) Further study should be made for other refractive indices of the aerosol particles. More refinement of the present multiple scattering code to include upwelling polarization components from below the sea surface is also necessary.