Showing papers on "Filter (video) published in 2000"

Guidewire filter and methods of use

Abstract: A filter system for temporary placement of a filter in an artery or vein is disclosed. The filter system includes a guidewire that is first positioned across a lesion within a vessel. The guidewire may include a distal stop. A slideable filter is then advanced along the guidewire using an advancing mechanism, typically an elongate member slideable over the guidewire and contacting the filter. A capture sheath may be disposed about the filter during advancement. Once the filter is positioned downstream of the lesion, the capture sheath is withdrawn, allowing the filter to expand. Further distal advancement of the filter is prohibited by the stop. After expansion of the filter, the capture sheath and the advancing mechanism are withdrawn from the region of interest, and removed from the patient's vessel. The filter may then be retrieved using a capture sheath or exchanged for a second filter after removing the first filter.

Intravascular filter and method

Abstract: A filter disposed at the distal end of an elongate guidewire. Catheters are provided for delivering the filter to, and retrieving the filter from, a treatment site. The catheters can be over-the-wire or single operator exchange. The catheters include a housing for receiving the filter therein. The housing has an atraumatic distal end.

Higher order filter response in coupled microring resonators

Abstract: Second- and third-order filter response is experimentally shown in filters constructed using mutually coupled microring resonators. The higher order filters have passbands with sharper rolloff and flatter tops, and greater out-of-band rejection than previously demonstrated microring filters, which were first order. The effect of varying interesonator coupling on filter passband shape was studied.

Methods and apparatus for controlling access to a resource

Abstract: An input/output interface receives an access request from a requester. A processor associated with the input/output interface applies a filter operation to select a subset of rules from a master set of rules maintained within an authorization database. Rules can be selected in this manner using filter operations so that all rules in the rule set need not be processed. A rule may include a disregard instruction. The processor further performs at least one rule operation based on the subset of rules to produce an access control decision in the memory system until either a rule operation including a disregard instruction is performed to limit performance of rule operations in the selected set of rules or until all rule operations in the selected set of rules that are applicable to the access control decision are performed.

Equalization of nonlinear time-varying channels using type-2 fuzzy adaptive filters

Abstract: Presents a kind of adaptive filter: type-2 fuzzy adaptive filter (FAF); one that is realized using an unnormalized type-2 Takagi-Sugeno-Kang (TSK) fuzzy logic system (FLS). We apply this filter to equalization of a nonlinear time-varying channel and demonstrate that it can implement the Bayesian equalizer for such a channel, has a simple structure, and provides fast inference. A clustering method is used to adaptively design the parameters of the FAF. Two structures are used for the equalizer: transversal equalizer (TE) and decision feedback equalizer (DFE). A decision tree structure is used to implement the decision feedback equalizer, in which each leaf of the tree is a type-2 FAF. This DFE vastly reduces computational complexity as compared to a TE. Simulation results show that equalizers based on type-2 FAFs perform much better than nearest neighbor classifiers (NNC) or equalizers based on type-1 FAFs.

A varactor-tuned RF filter

Abstract: An electronically tunable filter at 1 GHz is presented in this paper. The filter uses a suspended substrate design and commercially available varactors for filter tuning. The filter has a 60% tuning range from 700 MHz to 1.33 GHz with a low insertion loss (better than 3 dB from 1 to 1.33 GHz). This paper discusses the effects of the varactor series resistance and the electrical length of the distributed resonator on the overall resonator quality factor and filter insertion loss. The input third-order intermodulation product intercept point was measured to be better than 17 dBm across the entire tuning range.

Dynamics Filter - concept and implementation of online motion Generator for human figures

Abstract: Humanoid robots are required to make a variety of dynamics and even expressive motions in changing environments. However, the conventional methods for generating humanoid motions fail do achieve this requirement since they can only generate quite artificial and predefined motions through rather complicated optimization processes. In this paper, we propose the concept of "dynamics filter" which transforms a physically inconsistent motion into a consistent one, and provide an example of its implementation using feedback control and local optimization. The optimization is based on the equation of motion of constrained kinematic chains, which is derived from our previously proposed method for computing the dynamics of structure-varying kinematic chains. The proposed method can be applied to online motion generator of humanoid robots.

Honeycomb filter and ceramic filter assembly

Abstract: An integral ceramic filter assembly (39) is produced by adhering with a ceramic seal layer (15) outer surfaces of a plurality of filters (F1). Each of the filters is formed from a sintered porous ceramic body made of α-silicon carbide and having a specific ratio of filter length to filter cross-section. The ceramic filter assembly has a ceramic smoothing layer (16) applied to the outer surface of the assembly, which as a whole has a generally circular cross-section or generally oval cross-section. Also disclosed is an exhaust gas purification apparatus including the filter assembly.

The effects of filtered video on awareness and privacy

Abstract: Video-based media spaces are designed to support casual interaction between intimate collaborators. Yet transmitting video is fraught with privacy concerns. Some researchers suggest that the video stream be filtered to mask out potentially sensitive information. While a variety of filtering techniques exist, they have not been evaluated for how well they safeguard privacy.In this paper, we analyze how a blur and a pixelize video filter might impact both awareness and privacy in a media space. Each filter is considered at nine different levels of fidelity, ranging from heavily applied filter levels that mask almost all information, to lightly applied filters that reveal almost everything. We examined how well observers of several filtered video scenes extract particular awareness cues: the number of actors; their posture (moving, standing, seated); their gender; the visible objects (basic to detailed); and how available people look (their busyness, seriousness and approachability). We also examined the privacy-preserving potential of each filter level in the context of common workplace activities. Our results suggest that the blur filter, and to a lesser extent the pixelize filter, have a level suitable for providing awareness information while safeguarding privacy.

A 5-GHz CMOS wireless LAN receiver front end

Abstract: This paper presents a 12.4-mW front end for a 5-GHz wireless LAN receiver fabricated in a 0.24-/spl mu/m CMOS technology. It consists of a low-noise amplifier (LNA), mixers, and an automatically tuned third-order filter controlled by a low-power phase-locked loop. The filter attenuates the image signal by an additional 12 dB beyond what can be achieved by an image-reject architecture. The filter also reduces the noise contribution of the cascode devices in the LNA core. The LNA/filter combination has a noise figure of 4.8 dB, and the overall noise figure of the signal path is 5.2 dB. The overall IIP3 is -2 dBm.

New cross-coupled filter design using improved hairpin resonators

Abstract: Stepped-impedance resonators have been thoroughly studied in this paper. Two equations for odd- and even-mode resonance are derived from a new network model. The size and resonant frequencies of the resonator could then be designed based on these two equations. A new resonator-embedded cross-coupled filter, constructed by stepped-impedance hairpin resonators and miniaturized hairpin resonators is presented. This new filter is very compact and has lower spurious response. A 0/spl deg/ feed structure, which adds two transmission zeros to the filter response, is also studied. The two zeros are so close to the passband that the selectivity and out-of-band rejection of the filter are significantly increased. The design has been verified by experiment results.

Intravascular catheter filter with interlocking petal design and methods of use

Abstract: A filter device for temporary placement of a filter in an artery or vein is disclosed. The device includes an expandable filter mounted on a distal end of a catheter. The filter comprises a plurality of circumferentially adjacent porous segments that are arranged generally about the surface of a cone having an open base, and the segments are engaged to one another by means, such as a hook. The filter conforms to the interior of a vessel wall when expanded and contracts to a consistent diameter without bunching when stowed. Methods of using the filter device to entrap and remove embolic material from a vessel during endovascular procedures are also disclosed.

Multiple-model adaptive estimation using a residual correlation Kalman filter bank

Abstract: We propose a modified multiple model adaptive estimation (MMAE) algorithm that uses the time correlation of the Kalman filter residuals, in place of their scaled magnitude, to assign conditional probabilities for each of the modeled hypotheses. This modified algorithm, denoted the residual correlation Kalman filter bank (RCKFB), uses the magnitude of an estimate of the correlation of the residual with a slightly modified version of the usual MMAE hypothesis testing algorithm to assign the conditional probabilities to the various hypotheses that are modeled in the Kalman filter bank within the MMAE. This concept is used to detect flight control actuator failures, where the existence of a single frequency sinusoid (which is highly time correlated) in the residual of an elemental filter within an MMAE is indicative of that filter having the wrong actuator failure status hypothesis. This technique results in a delay in detecting the flight control actuator failure because several samples of the residual must be collected before the residual correlation can be estimated. However, it allows a significant reduction of the amplitude of the required system inputs for exciting the various system modes to enhance identifiability, to the point where they may possibly be subliminal, so as not to be objectionable to the pilot and passengers.

Blood-filter consists of two filter screens placed on connecting axis with facing concave sides and operated by catheter

Abstract: At least one, preferably two filter-screen(s) (3,4) is/are placed on a shared connecting axis (1) along which the filter-screens lie when folded up and from which the filter screens extend radially when tensioned. The filter screen is o operated by an operating catheter (2). The concave sides of the filter screens are opposite each other when tensioned. The filter screens are made of material through which natural blood constituents can pass unhindered.

Module for acquiring electroencephalograph signals from a patient

Abstract: A patient module comprising an 8 channel EEG pre-amplifier whose signal acquisition and processing characteristics are optimized for use in the operating room and intensive care unit. This patient module comprises at least an optimized multistage input filter (R4-C6), an optimized input stage circuit topography, ultra-isolation, oversampling, a multiplexer inter-sample charge dump, and high performance low-frequency-enhanced shielding.

Blood filter and method for treating vascular disease

Abstract: A filter is provided that is convertible from a filter configuration to an open, stent-like configuration. The filter includes a plurality of intraluminal filter elements (filter legs) that may be formed into a single cone or dual cone filter structure. A retainer secures the filter legs in the filter configuration upon initial deployment within a vessel. The retainer is then either self-releasing or removable to permit the filter legs to expand from the filter configuration into what may generally be described as an open or stent-like configuration. A filter web extends, at least in part, between the filter legs.

A probabilistic background model for tracking

Abstract: A new probabilistic background model based on a Hidden Markov Model is presented. The hidden states of the model enable discrimination between foreground, background and shadow. This model functions as a low level process for a car tracker. A particle filter is employed as a stochastic filter for the car tracker. The use of a particle filter allows the incorporation of the information from the low level process via importance sampling. A novel observation density for the particle filter which models the statistical dependence of neighboring pixels based on a Markov random field is presented. The effectiveness of both the low level process and the observation likelihood are demonstrated.

Body vessel filter

Abstract: A catheter-deliverable filter assembly deployable in a vessel of the body in alternatively a temporary configuration enabling the filter to be removed from the vessel or a permanent configuration, and a method for its use. The filter assembly comprises an elongated support carrying spaced along its length a filter element and a anchoring element with the filter element being spaced distally from the anchoring element. Each element comprises a core mounted to the elongated support and a plurality of flexible, resilient wires extending distally from the core, the wires having proximal portions attached at one end to the core and distal portions. The wires of the anchoring element include gripping elements for gripping the walls of a vessel. The wires are so configured as to support the apices of the filter and anchoring elements substantially in the center of the vessel. The filter assembly may include a hollow flexible tether releasably attached to the proximal end of the elongated support and having a distal end portion within which are resiliently confined the wires of the anchoring element when the filter element alone is deployed.

A 60-dB dynamic-range CMOS sixth-order 2.4-Hz low-pass filter for medical applications

Abstract: The design and implementation of a fully integrated complementary metal-oxide-semiconductor (CMOS) sixth-order 2.4 Hz low-pass fitter (LPF) for medical applications is presented. For the implementation of large-time constants both linearized operational transconductance amplifiers with reduced transconductance and impedance scalers schemes for grounded capacitors are employed. Experimental results for the filter have shown a dynamic range (DR) of 60 dB, while the harmonic distortion components are below -50 dB. The power consumption for the filter is below 10 /spl mu/W, the power supply is /spl plusmn/1.5 V, and the active area is 1 mm/sup 2/. The filter was fabricated in a double poly double metal 0.8 /spl mu/m CMOS process.

A Probabilistic Background Model for Tracking

Abstract: A new probabilistic background model based on a Hidden Markov Model is presented. The hidden states of the model enable discrimination between foreground, background and shadow. This model functions as a low level process for a car tracker. A particle filter is employed as a stochastic filter for the car tracker. The use of a particle filter allows the incorporation of the information from the low level process via importance sampling. A novel observation density for the particle filter which models the statistical dependence of neighboring pixels based on a Markov random field is presented. The effectiveness of both the low level process and the observation likelihood are demonstrated.

Phase-only optical encryption

Abstract: We have implemented a phase-only optical encryption and decryption system with a readout based on the generalized phase-contrast method. The experimental system has been implemented with liquid-crystal spatial light modulators to generate binary phase-encrypted masks and a decrypting key. A phase-contrast filter is used to display the phase information.

Filter synthesis for periodically coupled microring resonators.

Abstract: The theory of filter synthesis using periodically coupled microring resonators is developed as a means to overcome the fabrication sensitivities inherent in conventional higher-order filters, while still achieving desirable spectral characteristics. Each resonator in the array can compensate for deficiencies in any of the others. These filters exhibit a boxlike shape and very high extinction ratios.

Fault detection and identification in a mobile robot using multiple model estimation and neural network

Abstract: We propose a method to detect and identify faults in wheeled mobile robots. The idea behind the method is to use adaptive estimation to predict the outcome of several faults, and to learn them collectively as a failure pattern. Models of the system behavior under each type of fault are embedded in multiple parallel Kalman filter (KF) estimators. Each KF is tuned to a particular fault and predicts, using its embedded model, the expected values for the sensor readings. The residual, the difference between the predicted readings (based on certain assumptions for the system model and the sensor models) and the actual sensor readings, is used as an indicator of how well each filter is performing. A backpropagation neural network processes this set of residuals as a pattern and decides which fault has occurred, that is, which filter is better tuned to the correct state of the mobile robot. The technique has been implemented on a physical robot and results from experiments are discussed.

Programmable logic controller method, system and apparatus

Abstract: A programmable logic controller with enhanced and extended the capabilities. A digital input filter implement filters with considerable less logic by simulating the action of a capacitor being driven by a constant current source whose output voltage is sensed by a comparator with a large amount of hysterisis. A pulse catch circuit captures the input pulse even though the update occurs between scan cycles. A pulse output controller includes a hardware pipeline mechanism to allow for smooth, hardware-controlled transitions from wave-form to wave-form. A free port link allows the user to control the port either manually or by operation of a user program. In order to provide higher performance for communication using PPI protocol, the PLC includes a built-in protocol. An n-bit modem protocol ensures data integrity without use of a parity type data integrity system. A hide instruction protects proprietary software by encrypting the sensitive code and decrypting the code during compilation and, thereafter, re-encrypting the code. A system function call allows the user to create and/or download new PLC functions and implement them as PLC operating system functions. An STL status function debugs programs during run-time and while the program is executing. A micro PLC arrangement provides compact size and efficiency.

Efficient modified-sinc filters for sigma-delta A/D converters

Abstract: In this paper, a method to design and implement a very efficient multistage decimation filter for a sigma-delta (/spl Sigma//spl Delta/) A/D converter is proposed The scheme is composed of two stages, but the proposed method can be easily extended to a multiple-stage implementation The first-stage filter is obtained by properly rotating the zero-pole distribution of a comb filter in the z-plane The obtained structure exhibits linear phase and can be implemented by using a recursive structure with only two multipliers The design phase is easy and very flexible As most of the quantization noise is eliminated at the first stage, the second-stage filter can be designed with relaxed specifications Any classical design algorithm can be used for it An alternative scheme for the second stage can be obtained by splitting the stage into two substages, and the method proposed in this paper can be iterated

An Extended Adaptive Kalman Filter for Real-time State Estimation of Vehicle Handling Dynamics

Abstract: This paper considers a method for estimating vehicle handling dynamic states in real-time, using a reduced sensor set; the information is essential for vehicle handling stability control and is also valuable in chassis design evaluation. An extended (nonlinear) Kalman filter is designed to estimate the rapidly varying handling state vector. This employs a low order (4 DOF) handling model which is augmented to include adaptive states (cornering stiffnesses) to compensate for tyre force nonlinearities. The adaptation is driven by steer-induced variations in the longitudinal vehicle acceleration. The observer is compared with an equivalent linear, model-invariant Kalman filter. Both filters are designed and tested against data from a high order source model which simulates six degrees of freedom for the vehicle body, and employs a combined-slip Pacejka tyre model. A performance comparison is presented, which shows promising results for the extended filter, given a sensor set comprising three accelerometers only. The study also presents an insight into the effect of correlated error sources in this application, and it concludes with a discussion of the new observer's practical viability.

Assimilation of Stratospheric Chemical Tracer Observations Using a Kalman Filter. Part I: Formulation

Abstract: The first part of this two-part article describes the formulation of a Kalman filter system for assimilating limb-sounding observations of stratospheric chemical constituents into a tracer transport model. The system is based on a two-dimensional isentropic approximation, permitting a full Kalman filter implementation and a thorough study of its behavior in a real-data environment. Datasets from two instruments on the Upper Atmosphere Research Satellite with very different viewing geometries are used in the assimilation experiments. A robust chi-squared diagnostic, which compares statistics of the observed-minus-forecast residuals with those calculated by the filter algorithm, is used to help formulate the statistical inputs to the filter, as well as to tune covariance parameters and to validate the assimilation results. Two significant departures from the standard (discrete) Kalman filter formulation were found to be important in this study. First, it was discovered that the standard Kalman filt...

Video stream classifiable symbol isolation method and system

Abstract: An image processing device and method for classifying symbols relies on a connected-component technique for isolating symbol regions. The device and method form connected components from an image derived by the application of an edge detection filter. The formation of connected components from this filtered image defines the edges of character shapes. As a result, the number of pixels that must be connected to define each connected component is substantially reduced and the speed of processing thereby increased. The application of the method is discussed primarily with respect to text in a video stream.