Showing papers by "Mitsubishi Electric published in 1998"

Universal modem for digital video, audio and data communications

Abstract: A universal modem has a software-configurable modulator/demodulator which accommodates different modulation formats such as those associcated with terrestrial, cable, phone line, satellite and wireless communications to be transmitted and received through a single device in which the modem has reconfigurable logic to accommodate the format of the signals being received or transmitted. In one embodiment, the system tracks channel noise and changes modulation format at both the transmit and receive sides of the system through the use of a controller that controls both sides.

COLLAGEN: A Collaboration Manager for Software Interface Agents

Abstract: We have implemented an application-independent collaboration manager, called Collagen, based on the SharedPlan theory of discourse, and used it to build a software interface agent for a simple air travel application. The software agent provides intelligent, mixed initiative assistance without requiring natural language understanding. A key benefit of the collaboration manager is the automatic construction of an interaction history which is hierarchically structured according to the user‘s and agent‘s goals and intentions.

A Winnow-Based Approach to Context-Sensitive Spelling Correction

Abstract: A large class of machine-learning problems in natural language require the characterization of linguistic context. Two characteristic properties of such problems are that their feature space is of very high dimensionality, and their target concepts refer to only a small subset of the features in the space. Under such conditions, multiplicative weight-update algorithms such as Winnow have been shown to have exceptionally good theoretical properties. We present an algorithm combining variants of Winnow and weighted-majority voting, and apply it to a problem in the aforementioned class: context-sensitive spelling correction. This is the task of fixing spelling errors that happen to result in valid words, such as substituting "to" for "too", "casual" for "causal", etc. We evaluate our algorithm, WinSpell, by comparing it against BaySpell, a statistics-based method representing the state of the art for this task. We find: (1) When run with a full (unpruned) set of features, WinSpell achieves accuracies significantly higher than BaySpell was able to achieve in either the pruned or unpruned condition; (2) When compared with other systems in the literature, WinSpell exhibits the highest performance; (3) The primary reason that WinSpell outperforms BaySpell is that WinSpell learns a better linear separator; (4) When run on a test set drawn from a different corpus than the training set was drawn from, WinSpell is better able than BaySpell to adapt, using a strategy we will present that combines supervised learning on the training set with unsupervised learning on the (noisy) test set.

System for designing graphical multi-participant environments

Abstract: A system for generating a virtual reality environment applies principles of urban planning. Participants interact with the system by designating or changing certain objects or characteristics of the environment. The environment includes designation of districts having similar scenic characteristics. Paths define routes through the districts and within the environment. Specific foci or landmarks can be identified at locations within the environment. In addition to creating a conceptual view of the environment, the system generates a set of scenes representing movement of a participant along a defined walkway through the environment. The scenes are generated as composite images of objects in a perspective view. The objects forming a composite in the scene are determined based upon the characteristics of the district to which the scene applies.

Software pixel interpolation for digital still cameras suitable for a 32-bit MCU

Abstract: This paper discusses the interpolation technique applied to the Bayer primary color method, used frequently as the pixel structure of CCD image sensors for digital still cameras. Eight typical types of interpolation methods are discussed from three viewpoints: the characteristics of the interpolated images, the processing time required to realize their methods based on a 32-bit MCU for embedded applications, and the quality of the resultant images. In terms of reducing the occurrences of pseudocolor and achieving good color restoration, the linear interpolation method taking G's correlation determined by using R/B pixels into consideration was found to be excellent. The measured machine cycle of the interpolation methods was approximately 46 cycles per pixel. Therefore, every method was able to interpolate a VGA-size image in approximately 0.2 seconds with the MCU operating at 60 MHz. In terms of the S/N ratio, a good image quality was obtained through the linear interpolation methods, even with shorter processing time. Based on these results it is concluded that the linear interpolation method, which takes correlation into consideration, is the most suitable for consumer product applications such as digital still cameras.

Using distance maps for accurate surface representation in sampled volumes

Abstract: High quality rendering and physics based modeling in volume graphics have been limited because intensity based volumetric data do not represent surfaces well. High spatial frequencies due to abrupt intensity changes at object surfaces result in jagged or terraced surfaces in rendered images. The use of a distance-to-closest-surface function to encode object surfaces is proposed. This function varies smoothly across surfaces and hence can be accurately reconstructed from sampled data. The zero value iso surface of the distance map yields the object surface and the derivative of the distance map yields the surface normal. Examples of rendered images are presented along with a new method for calculating distance maps from sampled binary data.

Master/slave system for the manipulation of tubular medical tools

Abstract: A master/slave system is used for performing a surgical procedure such as theterization of cardiac or peripheral vasculature. Movements of catheters or similar tools within a patient are remotely controlled by a surgeon, and the surgeon receives haptic or tactile feedback caused by the movement of the tools within the patient. The system employs a master actuator with cylindrical controls and a slave actuator that engages the tools. The master actuator and slave actuator are electrically coupled to electrical interface circuitry by drive signals and sense signals. A fluid system is coupled to the slave actuator by fluid-carrying tubes for the delivery of contrast and other solutions to be injected into the vasculature for improved imaging and also to pressurize the balloon on a balloon catheter. The master and slave actuators contain sensors that sense translation and rotation of the controls and tools with respect to their longitudinal axes, and provide sense signals indicative of these motions to the interface circuitry. The master and slave actuators also contain motors respectively engaging the controls and tools to cause translational and rotational movement of these components in response to the drive signals generated by the interface circuitry. The interface circuitry contains a processor executing a master/slave control program via which the relative positions of each control and the corresponding tool are made to track each other. The control program can optionally implement force scaling, position scaling, tremor reduction, and other features to enhance the system's performance.

A system for reconstructing the 3-dimensional motions of a human figure from a monocularly-viewed image sequence

Abstract: A system is provided for reconstruction the 3-dimensional motions of a human figure from a monocularly viewed image sequence in which a statistical approach is used coupled with the use of a set of motion capture examples to build a gaussian probability model for short human motion sequences. In a simplified rendering domain, this yields an optimal 3-d estimate of human motion used to create realistic animations given a 2-d temporal sequence. The subject system is also useful to identify which motion modes are difficult to estimate. In one embodiment, a stick figure is overlaid on the input video image to allow manual correction of incorrectly tracked body parts. The utilization of stick figure correction permits manual correction for a more accurate 3-d reconstruction of the motion depicted in the input video sequence. An interactive tracking system processes real video sequences, and achieves good 3-d reconstructions of the human figure motion.

Adaptive video coding method

Abstract: In accordance with the present invention, a method is described which achieves a constant bit rate output when coding multiple video objects. This implementation makes use of a quadratic rate-distortion model. Each object is described by its own set of parameters. With these parameters, an initial target bit estimate is made for each object after a first frame is encoded. Based on output buffer fullness, the total target is adjusted and then distributed proportional to a parameter set representative of the activity of the objects in the frame. Activity is determined by reference to weighted ratios derived from motion, size and variance parameters associated with each object. A shape rate control parameter is also invoked. Based on the new individual targets and second order model parameters, appropriate quantization parameters can be calculated for each video object. This method assures that the target bit rate is achieved for low latency video coding. In order to provide a suitable bit rate control system based on a quadratic rate-distortion model, it has been found that control information may be applied jointly with respect to video objects (VO's), rather than entire frames.

A low power SRAM using auto-backgate-controlled MT-CMOS

Abstract: We have been proposed a low power SRAM using an effective method called “ABC-MT-CMOS” [1]. It controls the backgates to reduce the leakage current when the SRAM is not activated (sleep mode) while retaining the data stored in the memory cells. We also adopted a “CSB Scheme” which clamps both the source lines of the memory cell array and the bit lines. We designed and fabricated test chips containing a 32K-bit gate array SRAM. The experimental results show that the leakage current is reduced to 1/1000 in sleep mode. The active power is 0.27 mW/MHz at 1 V, which is a reduction of 1/12 of a conventional SRAM with a 3.3 V.

Semiconductor device with improved noise resistivity

Abstract: A dummy pattern that is inserted to stabilize the form of a transistor active region is implanted with an impurity of the same conductivity type as a well, and the impurity-doped region of the dummy pattern is supplied with a potential through a metal interconnection. Hence, fluctuation of a well potential due to noise hardly occurs, and a semiconductor device enduring latch up, for example, to a greater extent can be provided.

Mobile communication device and mobile communication system

Abstract: A mobile communication device for receiving service by a ground communication system in the service area thereof and by a satellite communication system outside the service area. The mobile communication device comprises a section for monitoring the service receiving state of the satellite communication system, a section for storing information on the service area of the ground communication system, a section for judging whether or not the current position is in the service area of the ground communication system based on the service area information stored in the memory section when deterioration of service receiving state of the satellite communication system is detected by the state monitoring section, and a switching control section for sustaining the service receiving state of the satellite communication system when it is judged that the current position is outside the service area and switching the service receiving state of the satellite communication system to the service receiving state of the ground communication system when the current position is in the service area.

Experimental investigation of high frequency voltage oscillation in transformer windings

Abstract: Very fast transient overvoltages (VFTO) comprising oscillating waveforms generate a voltage oscillation in transformer windings. The behaviour of the voltage oscillation in the winding is investigated experimentally on 500 kV class transformers using a pulse and a sinusoidal voltage. The interturn voltages are directly measured using an optical fiber transmission system. In the case of a pulse application, it is found that an interturn traveling wave is generated at either end of the coil and propagates along the winding. In the case of a sinusoidal voltage application, a resonance phenomenon, probably due to the superposition of the traveling waves, is found in the interturn voltage, which could reach 0.25 times the applied voltage. In the tested transformers, the estimated interturn voltage level at incoming VFTO can be 3 times higher than that in the lightning impulse voltage test.

File version reconciliation using hash codes

Abstract: A file reconciliation process in a distributed file system uses a set of journal or log files to track the history of file modification at each of different sites, or sets of directories, in a computer system During reconciliation, sequences of version entries associated with each file in each journal are updated and compared to determine whether (1) a conflict exists for any of the files involved in the reconciliation, and (2) if not, which version of the file is the current version The version entries contain a hash code or digest that to a high probability uniquely identifies the contents of a file Sequences of hash codes are used to identify the sequence of file versions Masks and site indicator fields are included in the journal files and used to track which journal files have copies of version entries for the purpose of deleting version entries when they become obsolete

A new automatic exposure system for digital still cameras

Abstract: This paper presents a newly developed automatic exposure (AE) system for digital still cameras (DSC). The through the lens (TTL) system which has been employed mainly by conventional camcorders has been applied as an exposure control system for DSCs. However, the TTL system requires a longer time to obtain an appropriate exposure value, and it is therefore not a suitable control method for DSCs which demand immediate imaging after the shutter button is pushed. The authors have developed a high-precision AE capable of controlling the exposure quickly by converting the brightness of an object directly using the obtained value of an integrated image without using the photometric sensors other than a charge coupled device (CCD). They have also confirmed that the new system enables excellent exposure control without any problem.

Using Windows NT for real-time applications: experimental observations and recommendations

Abstract: Windows NT was not designed as a real time operating system, but market forces and the acceptance of NT in industrial applications have generated a need for achieving real time functionality with NT As its use for real time applications proliferates, based on an experimental evaluation of NT, we quantitatively characterize the obstacles placed by NT As a result of these observations, we provide a set of recommendations for users to consider while building real time applications on NT These are validated by the use of NT for a prototype application involving real time control that includes multimedia information processing The results of the above study should provide system designers with guidelines, as well as insight, into the design of an architecture based on NT for supporting applications with components having real time constraints

Learning to Estimate Scenes from Images

Abstract: We seek the scene interpretation that best explains image data. For example, we may want to infer the projected velocities (scene) which best explain two consecutive image frames (image). From synthetic data, we model the relationship between image and scene patches, and between a scene patch and neighboring scene patches. Given a new image, we propagate likelihoods in a Markov network (ignoring the effect of loops) to infer the underlying scene. This yields an efficient method to form low-level scene interpretations. We demonstrate the technique for motion analysis and estimating high resolution images from low-resolution ones.

A Practical Implementation of Elliptic Curve Cryptosystems over GF(p) on a 16-bit Microcomputer

Abstract: Recently the study and implementation of elliptic curve cryptosystems (ECC) have developed rapidly and its achievements have become a center of attraction. ECC has the advantage of high-speed processing in software even on restricted environments such as smart cards. In this paper, we concentrate on implementation of ECC over a field of prime characteristic on a 16-bit microcomputer M16C (10MHz). We report a practical software implementation of a cryptographic library which supports 160-bit elliptic curve DSA (ECDSA) signature generation, verification and SHA-1 on the processor. This library also includes general integer arithmetic routines for applicability to other cryptographic algorithms. We successfully implemented the library in 4Kbyte code/data size including SHA-1, and confirmed a speed of 150msec for generating an ECDSA signature and 630msec for verifying an ECDSA signature on M16C.

Biomechanical Simulation of the Vitreous Humor in the Eye Using and Enhanced ChainMail Algorithm

Abstract: The focus of this paper is the newly developed Enhanced ChainMail Algorithm that will be used for modeling the vitreous humor in the eye during surgical simulation. The simulator incorporates both visualization and biomechanical modeling of a vitrectomy, an intra-ocular surgical procedure for removing the vitreous humor. The Enhanced ChainMail algorithm extends the capabilities of an existing algorithm for modeling deformable tissue, 3D ChainMail, by enabling the modeling of inhomogeneous material. In this paper, we present the enhanced algorithm and demonstrate its capabilities in 2D.

Development of advanced arresters for GIS with new zinc-oxide elements

Abstract: New zinc-oxide elements with a varistor voltage about twice that of conventional ones of the same thickness have been developed by reducing the ZnO grain size with a new additive, which enable a halving of the series number of elements in metal oxide surge arresters. The advanced arresters with these elements for GIS are compact by 40 to 60% in volume compared with conventional ones. The electrical and mechanical performance of the advanced arresters was found to be satisfactory through various evaluation tests such as thermal stability tests, residual voltage tests, seismic tests and long-term stability tests.

Bayesian Modeling of Facial Similarity

Abstract: In previous work [6, 9, 10], we advanced a new technique for direct visual matching of images for the purposes of face recognition and image retrieval, using a probabilistic measure of similarity based primarily on a Bayesian (MAP) analysis of image differences, leading to a "dual" basis similar to eigenfaces [13]. The performance advantage of this probabilistic matching technique over standard Euclidean nearest-neighbor eigenface matching was recently demonstrated using results from DARPA's 1996 "FERET" face recognition competition, in which this probabilistic matching algorithm was found to be the top performer. We have further developed a simple method of replacing the costly compution of nonlinear (online) Bayesian similarity measures by the relatively inexpensive computation of linear (offline) subspace projections and simple (online) Euclidean norms, thus resulting in a significant computational speed-up for implementation with very large image databases as typically encountered in real-world applications.

Infrared focal plane array

Abstract: A two-dimensional infrared focal plane array comprising temperature detecting units in which one temperature detecting unit is arranged for each pixel in a two-dimensional arrangement on a semiconductor substrate, said temperature detecting unit being formed integrally with a thermal type light detector and a means for detecting a change in characteristic of said thermal type light detector, said change being caused by an incident infrared ray, wherein a temperature detecting portion which is supported by support legs comprising a high thermal resistance material capable of controlling a heat flow to said semiconductor substrate and which has a temperature detecting element, and an infrared ray absorbing portion are provided for each pixel on said semiconductor substrate, characterized in that said infrared ray absorbing portion is spliced by at least one splicing pillar with said temperature detecting portion, and said infrared ray absorbing portion comprises silicon dioxide or silicon nitride, or a laminate film of silicon dioxide and silicon nitride, and wherein the thermal resistance of the splicing pillar is smaller than the thermal resistance of the support legs.

Portable cellular phone having the function of a camera

Abstract: A portable cellular phone includes audio input means, transmission means for transmitting to a calling/called party audio information converted by the input means, character information input means, and character memory. The portable cellular phone further includes a digital camera which photographs an image and outputs image information, image memory which stores the image information, a system control section which links the image information of the digital camera or of the image memory to character information of the character memory, display means which displays linked information items, and changeover means which switches the image information received from the image memory to audio information in such a way that means for transmitting the audio information transmits the image information.

Data receiver having variable rate symbol timing recovery with non-synchronized sampling

Abstract: An adaptable, variable rate symbol timing recovery system for a digital signal receiver comprises an analog to digital (A-D) signal converter having analog signal input and digital data signal output terminals. A source of selectable, substantially fixed rate, data sampling clock signals is coupled to the A-D signal converter for sampling a signal received at the input at a predetermined, substantially fixed clock rate, depending on data rate and modulation of the received signal. A digital signal processing loop is coupled to the digital data signal output terminal for adjustably producing interdependent signals in synchronism with the data signals at said output terminal which are asynchronous with respect to the fixed rate clock signals. A Controller is provided for selectively configuring the data sampling clock signal source and the digital signal processing loop according to the data rate and modulation characteristics of the said received signal.

Interferometric crosstalk-free optical add/drop multiplexer using Mach-Zehnder-based fiber gratings

Abstract: Mach-Zehnder interferometers with fiber Bragg gratings (MZ-FG) are investigated as promising devices for wavelength-selectable optical add-and-drop multiplexers (OADM). A wavelength reused OADM performance is demonstrated for the first time to our knowledge in a six-channel, 10 Gb/s WDM experiment using a single-stage MZ-FG. We discuss both theoretically and experimentally the interferometric crosstalk induced by imperfect Bragg-reflectivity. Two methods are proposed to solve the interferometric crosstalk issues. The first one is wavelength offset scheme. It is experimentally confirmed that there is no interference when the wavelength of crosstalk is away from that of the signal at least two times of bit-rate. In order to separate each wavelength, the master-slave wavelength control method is proposed with Fabry-Perot interferometer made of a set of fiber gratings. The second one is a cascaded MZ-FG scheme eliminating the crosstalk itself. The calculation indicates that a Bragg-reflectivity of only 93% can suppress the crosstalk to be -35 dB. Cascaded MZ-FG's have been fabricated to show that the interferometric crosstalk can be successfully reduced to -50 dB for the add signal, and -71 dB for the drop signal, respectively. The eight-wavelength 10 Gb/s OADM experiment is carried out to demonstrate the low interferometric crosstalk performance.

Motion compensated digital video signal processing

Abstract: A method determines true motion vectors associated with a sequence of images. The images include fields made up of blocks of pixels. The method selects candidate feature blocks from the blocks of pixels. The candidate feature blocks have intensity variances above a threshold indicative of texture features. Candidate feature blocks in similarly numbered adjacent field intervals are compared to determine sets of displaced frame differences parameters for each candidate feature block. The true motion vectors for each candidate feature block are determined from a minimum weighted score derived from the difference parameters.

A New Missile Guidance Algorithm Against A Maneuvering Target

Abstract: Our former studies has shown the general superiority of augmented proportional navigation over conventional proportional navigation. However, there were some exceptions where the latter has shown a better performance than the former. The farther study result showed that, the conventional proportional navigation is favorable against the aircraft in-coplane maneuver, while augmented proportional navigation is superior to the former against the aircraft out-of-coplane maneuver, even in cases where a fairly large time lag exists in the target acceleration estimation. Motivated by the fact, a new missile guidance algorithm which switches between conventional and augmented proportional navigation depending on the kind of the aircraft maneuver is studied and the performance is evaluated by simulations. The result shows the general superiority of this guidance algorithm over existent conventional or augmented proportional navigation guidance.

Real-time PC based volume rendering system

Abstract: Apparatus is provided to enable real-time volume rendering on a personal computer or a desktop computer in which a technique involving blocking of voxel data organizes the data so that all voxels within a block are stored at consecutive memory addresses within a single memory model, making possible fetching an entire block of data in a burst rather than one voxel at a time. This permits utilization of DRAM memory modules which provide high capacity and low cost with substantial space savings. Additional techniques including sectioning reduces the amount of intermediate storage in a processing pipeline to an acceptable level for semiconductor implementation. A multiplexing technique takes advantage of blocking to reduce the amount of data needed to be transmitted per block, thus reducing the number of pins and the rates at which data must be transmitted across the pins connecting adjacent processing modules with each other. A mini-blocking technique saves the time needed to process sections by avoiding reading entire blocks for voxels near the boundary between a section and previously processed sections.