The paper provides the algorithm to estimate the deviation bound admitting to recovering irregularly sampled signals in wavelet subspaces, which does not need the symmetricity sampling constraint of Paley-Wiener's and relaxes the deviation bounds in some wavelet subspaces. Meanwhile the method does not need the continuity and decay constraints imposed on scaling functions by Liu-Walter and Chen-Itoh-Shiki.

In this paper, two types of improved CMRR CMOS OAs, N type and P type, without common-mode feedback and the cascode current mirrors, are proposed. The CMRR of proposed OAs are enhanced by compensating variations in tail bias current, caused by a common mode input signal, at the differential input stage, by means of feedforward controlled current source. Simulation results show that the CMRR of the proposed OAs are 20dB higher than that of conventional OAs.

A method of motion segmentation in RGB image sequences is presented in details. The method is based on moving object modeling by a six-variate Gaussian distribution and a hidden Markov random field (MRF) framework. It is an extended and improved version of our previous work. Based on mathematical principles the energy expression of MRF is modified. Moreover, an initialization procedure for the first frame of the sequence is introduced. Both modifications result in new interesting features. The first involves a rather simple parameter estimation which has to be performed before the use of the method. Now, the values of Maximum Likelihood (ML) estimators of the parameters can be used without any user's modifications. The last allows one to avoid finding manually the localization mask of moving object in the first frame. Experimental results showing the usefulness of the method are also included.

We propose a theory of general frame multiresolution analysis (GFMRA) which generalizes both the theory of multiresolution analysis based on an affine orthonormal basis and the theory of frame multiresolution analysis based on an affine frame to a general frame. We also discuss the problem of perfectly representing a function by using a wavelet frame which is not limited to being of affine type. We call it a "generalized affine wavelet frame." We then characterize the GFMRA and provide the necessary and sufficient conditions for the existence of a generalized affine wavelet frame.

According as the fine LSI process technique develops, the technique to reduce power dissipation of high-frequency integrated analog circuits is getting more important. This paper describes a design of high-frequency integrator with low power dissipation for monolithic leapfrog filters. In the design of the conventional monolithic integrators, there has been a great dfficulty that a high-frequency integrator which can operate at low supply voltage cannot be realized without additional circuits, such as unbalanced-to-balanced conversion circuits and common-mode feedback circuits. The proposed integrator is based on the Miller integrator. By a PNP current mirror circuit, high CMRR is realized. However, the high-frequency characteristic of the integrator is independent of PNP transistors. In addition, it can operate at low supply voltage. The excess phase shift of the integrator is compensated by insertion of the compensation capacitance. The effectiveness of the proposed technique is confirmed by PSPICE simulation. The simulation results of the integrator shows that the common-mode gain is efficiently low and the virtual ground is realized, and that moderate phase compensation can be achieved. The simulation results of the 3rd-order leapfrog filter using the integrator shows that the 50 MHz-cutoff frequency filter is obtained. Its power dissipation in operating 2 V-supply voltage is 5.22 mW.

A dynamic measurement method of static R/W skew caused by MR-Inductive element alignment error is discussed. A geometrical model for the displacement between a write gap and a read gap on a swing arm is formulated. A measurement method wthich employs read-after-write procedure on disk surfaces in a drive is proposed. A simulation results is reported. It contributes to increase the track densities of HDDs using MR/Inductive heads in the region of more than 200 TPMM (5000 TPI).

A vertical magnetoresistive (MR)/inductive head using the current bias technique has been developed for high-density magnetic recording. In this head, the sense current is orthogonal to the air-bearing surface (ABS). The area exposed at the ABS of the MR element is beneath the front lead, and the active area of the sensor is positioned behind that area. The MR element is composed of two permalloy films separated by a thin nonmagnetic material. The easy axis of the films is oriented parallel to the ABS and the films are magnetostatically coupled. The magnetic field created by the sense current is applied in the direction of the easy axis and the MR element is stabilized. In this head structure, no MR-element-stabilizing layer, such as an antiferromagnetic film or a hard magnetic film, is needed. Since the permalloy film beneath the front lead acts as a front flux guide, the signal flux propagates in the sensing area of the MR element behind the ABS. The new vertical MR head has the same electrical performance characteristics as the conventional horizontal MR head. The offtrack signal profile is symmetric against the track center because the magnetization of the two permalloy films rotates symmetrically in the signal-flux direction. The output signal level of this head is independent of the read trackwidth, which favors a narrow trackwidth. The exposed portion at the ABS is only connected to the common lead and is at ground potential. In this design, electrostatic breakdown does not occur and no corrosion is observed. Tests have shown that as the flying height is reduced, the error rate is reduced and noise does not increase. This head structure appears suitable for the near-contact recording of the near future.

Three-dimensional vocal tract shapes of a male, a female and a child subjects are measured from magnetic resonance (MR) images during sustained phonation of Japanese vowels /a, i, u, e, o/. Non-uniform dimensional differences in the vocal tract shapes of the subjects are quantitatively measured. Vocal tract area functions of the female and child subjects are normalized to those of the male on the basis of non-uniform and uniform scalings of the vocal tract length and compared with each other. A comparison is also made between the formant frequencies computed from the area functions normalized by the two different scalings. It is suggested by the comparisons that non-uniformity in the vocal tract dimensions is not essential in the normalization of the five Japanese vowels.

Though the electromagnetic technology has been contributing to the evolution of MRI, there are remaining problems to be worked out. With some introduction, this paper explains such problems focusing on the gradient coil design, RF coil design and RF safety consideration. For accurate, high-speed control of the gradient field, a new technology, shielded gradient coil has started playing an important role. The efficient design of such a coil requires a robust and efficient optimization tool that still has room for improvement. We propose to use the stored energy as the most important optimization parameter that may make the optimization process more efficient. Phased array RF coil, that widens the field of view while maintaining high SNR of a small RF coil, is a recent technology. For this, the system needs to have high capacity to acquire and process the data. To mitigate this problem, we are working on the combination of rather conventional QD technology with phased array. RF shielding between gradient coil and RF coil is becoming a serious problem with the evolution of high speed imaging techniques, and a complete solution is not yet demonstrated. We also discuss the difficulty of rigorous control of RF heating in patients. Practical method to predict local SAR needs to be developed.

Analysis of the specific absorption rate (SAR) of a realistic head model generated with a 1.5-tesla MRI antenna is described. It is found that the SAR of the eyeball is strongly affected by the position of the feeding point, whereas the sensitivity of the antenna is virtually independent of the feeding point.

This paper focuses on Mixed Reality (MR) visual displays, a particular subset of Virtual Reality (VR) related technologies that involve the merging of real and virtual worlds somewhere along the virtuality continuum" which connects completely real environments to completely virtual ones. Probably the best known of these is Augmented Reality (AR), which refers to all cases in which the display of an otherwise real environment is augmented by means of virtual (computer graphic) objects. The converse case on the virtuality continuum is therefore Augmented Virtuality (AV). Six classes of hybrid MR display environments are identified. However, an attempt to distinguish these classes on the basis of whether they are primarily video or computer graphics based, whether the real world is viewed directly or via some electronic display medium, whether the viewer is intended to feel part of the world or on the outside looking in, and whether or not the scale of the display is intended to map orthoscopically onto the real world leads to quite different groupings among the six identified classes, thereby demonstrating the need for an efficient taxonomy, or classification framework, according to which essential differences can be identified. The obvious' distinction between the terms real" and virtual" is shown to have a number of different aspects, depending on whether one is dealing with real or virtual objects, real or virtual images, and direct or non-direct viewing of these. An (approximately) three dimensional taxonomy is proposed, comprising the following dimensions: Extent of World Knowledge (how much do we know about the world being displayed?"), Reproduction Fidelity (how realistically' are we able to display it?"), and Extent of Presence Metaphor (what is the extent of the illusion that the observer is present within that world?").

We have classified parenchymal echo patterns of cirrhotic liver into 3 types, according to the size of hypoechoic nodular lesions. We have been studying an ultrasonic image diagnosis system using the three–layer back–propagation neural network. In this paper, we will describe the applications of the neural network techniques for recognizing and classifying chronic liver disease, which use the nodular lesions in the Proton density and T2–weighed magnetic resonance images on the gray level of the pixels in the region of interest.

Parallel processing in speech recognition is described, which is carried out at each frame on time axis. We have already proposed a parallel processing algorithm for HMM (Hidden Markov Model)-based speech recognition using Markov Random Fields (MRF). The parallel processing is realized by modeling the hidden state sequence by an MRF and using the Iterated Conditional Modes (ICM) algorithm to estimate the optimal state sequence given an observation sequence and model parameters. However this parallel processing with the ICM algorithm is applicable only to the standard HMM but not to the improved HMM like the linear predictive HMM which takes into account the correlations between nearby observation vectors. In this paper we propose a parallel processing algorithm applicable to the correlation-considered HMM, where a new deterministic relaxation algorithm called the Generalized ICM (GICM) algorithm is used instead of the ICM algorithm for estimation of the optimal state sequence. Speaker independent isolated word recognition experiments show the effectiveness of the proposed parallel processing using the GICM algorithm.

A slotted tube resonator (STR) having a shield of conducting circular cylinder which is used as a probe for the magnetic resonance imaging (MRI) is analyzed by using the variational method and the dyadic Green's function of a circular waveguide. Three surface current modes are employed to expand the currents on the STR. Quadruple integrals appearing in the variational expression are evaluated analytically for saving the CPU time. Resonant frequency, Q value and the magnitude of magnetic field distributions for various radii of the shields are obtained to show the effects of the shield. Some measured date are compared with the theoretical results to confirm the validity of the present analysis.

An adaptive restoration algorithm is developed for binary images degraded nonadditively with flip noises. The true image is assumed to be a realization of a Markov Random Field (MRF) and the nonadditive flip noises are assumed to be statistically independent and asymmetric. Using the Expectation and Maximization (EM) method and approximating the Baum's auxiliary function, the degraded image is restored iteratively. The algorithm is implemented as follows. First, the unknown parameters and the true image are guessed or estimated roughly. Second, using the true image estimate, the Baum's auxiliary function is approximated and then the noise and MRF parameters are reestimated. To reestimate the MRF parameters the Maximum Pseudo-likelihood (MPL) method is used. Third, using the Iterated Conditional Modes (ICM) method, the true image is reestimated. The second and third steps are carried out iteratively until by some ad hoc criterion a critical point of EM algorithm is approximated. A number of simulation examples are presented which show the effectiveness of the algorithm and the parameter estimation procedures.