Showing papers on "Filter (video) published in 2003"

Adaptive deblocking filter

Abstract: This paper describes the adaptive deblocking filter used in the H.264/MPEG-4 AVC video coding standard. The filter performs simple operations to detect and analyze artifacts on coded block boundaries and attenuates those by applying a selected filter.

Grid current regulation of a three-phase voltage source inverter with an LCL input filter

Abstract: Many grid connected power electronic systems, such as STATCOMs, UPFCs, and distributed generation system interfaces, use a voltage source inverter (VSI) connected to the supply network through a filter. This filter, typically a series inductance, acts to reduce the switching harmonics entering the distribution network. An alternative filter is a LCL network, which can achieve reduced levels of harmonic distortion at lower switching frequencies and with less inductance, and therefore has potential benefits for higher power applications. However, systems incorporating LCL filters require more complex control strategies and are not commonly presented in literature. This paper proposes a robust strategy for regulating the grid current entering a distribution network from a three-phase VSI system connected via a LCL filter. The strategy integrates an outer loop grid current regulator with inner capacitor current regulation to stabilize the system. A synchronous frame PI current regulation strategy is used for the outer grid current control loop. Linear analysis, simulation, and experimental results are used to verify the stability of the control algorithm across a range of operating conditions. Finally, expressions for ""harmonic impedance" of the system are derived to study the effects of supply voltage distortion on the harmonic performance of the system.

The normalized normal constraint method for generating the Pareto frontier

Abstract: The authors recently proposed the normal constraint (NC) method for generating a set of evenly spaced solutions on a Pareto frontier – for multiobjective optimization problems. Since few methods offer this desirable characteristic, the new method can be of significant practical use in the choice of an optimal solution in a multiobjective setting. This paper’s specific contribution is two-fold. First, it presents a new formulation of the NC method that incorporates a critical linear mapping of the design objectives. This mapping has the desirable property that the resulting performance of the method is entirely independent of the design objectives scales. We address here the fact that scaling issues can pose formidable difficulties. Secondly, the notion of a Pareto filter is presented and an algorithm thereof is developed. As its name suggests, a Pareto filter is an algorithm that retains only the global Pareto points, given a set of points in objective space. As is explained in the paper, the Pareto filter is useful in the application of the NC and other methods. Numerical examples are provided.

Texture classification: are filter banks necessary?

Abstract: We question the role that large scale filter banks have traditionally played in texture classification. It is demonstrated that textures can be classified using the joint distribution of intensity values over extremely compact neighborhoods (starting from as small as 3 /spl times/ 3 pixels square), and that this outperforms classification using filter banks with large support. We develop a novel texton based representation, which is suited to modeling this joint neighborhood distribution for MRFs. The representation is learnt from training images, and then used to classify novel images (with unknown viewpoint and lighting) into texture classes. The power of the method is demonstrated by classifying over 2800 images of all 61 textures present in the Columbia-Utrecht database. The classification performance surpasses that of recent state-of-the-art filter bank based classifiers such as Leung & Malik, Cula & Dana, and Varma & Zisserman.

Direct repetitive control of SPWM inverter for UPS purpose

Abstract: A novel repetitive controller directly combined with an open loop SPWM inverter is presented in this paper. To cope with the high-resonant peak of the open loop inverter that may cause instability, a zero-phase-shift notch filter other than the inverse transfer function of the inverter or a conventional second-order filter is incorporated in the controller. The proposed method has good harmonic rejection and large tolerance to parameter variations. To further reduce the steady-state error, a low-pass-filter Q(z) algorithm is applied. The DC bias problem is also taken into consideration and solved with the repetitive controller itself. The method is implemented with a digital signal processor and achieves low THD% (1.4%-1.7%) with nonlinear loads and fast error convergence (3-5 fundamental periods). It proves to be a cost-effective solution for common UPS products where high-quality output voltage is more stressed than fast dynamic response.

Output filter design for a grid-interconnected three-phase inverter

Abstract: Traditionally, LC filter is used for an inverter power supply. A grid-interconnected inverter, however, has some unique requirements that an LC filter may not be sufficient. This paper comprehensively discusses the design considerations of the output filter for the grid-interconnected inverter. Different passive damping filter solutions are compared and the optimized design guidelines are also proposed. Simulation results are provided to validate the design.

Genetic algorithm based design of the active damping for a LCL-filter three-phase active rectifier

Abstract: The use of a LCL-filter mitigates the switching ripple injected in the grid by a three-phase active rectifier. However stability problems could arise in the current control loop. In order to overcome them a damping resistor can be inserted, at the price of a reduction of the efficiency. On the contrary the use of the active damping seems really attractive but it is often limited by the use of more sensors respect to the standard control and by the complex tuning procedure. This paper introduces a new active damping method that does not need the use of more sensors and that can be tuned using genetic algorithms. It consists of adding a filter on the reference voltage for the converter's modulator. The tuning process of this filter is easily done, for a wide range of sampling frequencies, with the use of genetic algorithms. This method is used only for the optimum choice of the parameters of the filter and an on-line implementation is not needed. Thus the resulting active damping solution does not need new sensors or complex calculations. Moreover, in the paper particular attention is devoted to the dynamics of the system due to the introduction of the active damping.

The trilateral filter for high contrast images and meshes

Abstract: We present a new, single-pass nonlinear filter for edge-preserving smoothing and visual detail removal for N dimensional signals in computer graphics, image processing and computer vision applications. Built from two modified forms of Tomasi and Manduchi's bilateral filter, the new "trilateral" filter smoothes signals towards a sharply-bounded, piecewise-linear approximation. Unlike bilateral filters or anisotropic diffusion methods that smooth towards piecewise constant solutions, the trilateral filter provides stronger noise reduction and better outlier rejection in high-gradient regions, and it mimics the edge-limited smoothing behavior of shock-forming PDEs by region nding with a fast min-max stack. Yet the trilateral filter requires only one user-set parameter, filters an input signal in a single pass, and does not use an iterative solver as required by most PDE methods. Like the bilateral filter, the trilateral filter easily extends to N-dimensional signals, yet it also offers better performance for many visual applications including appearance-preserving contrast reduction problems for digital photography and denoising polygonal meshes.

Interacting multiple model particle filter

Abstract: A new method for multiple model particle filtering for Markovian switching systems is presented. This new method is a combination of the interacting multiple model (IMM) filter and a (regularised) particle filter. The mixing and interaction is similar to that in a conventional IMM filter. However, in every mode a regularised particle filter is running. The regularised particle filter probability density is a mixture of Gaussian probability densities. The proposed method is able to deal with nonlinearities and non-Gaussian noise. Furthermore, the new method keeps a fixed number of particles in each mode, and therefore it does not suffer from the potential drawbacks of existing multiple model particle filters for Markovian switching systems.

A compact second-order LTCC bandpass filter with two finite transmission zeros

Abstract: A novel implementation and associated design formula for a compact low-temperature cofired ceramics (LTCC) lumped-element second-order bandpass filter are proposed in this paper. The filter schematic that provides two finite transmission zeros is well known. It is shown in the paper that the filter schematic is built on a pair of conventional inductive coupled resonator tanks with a feedback capacitor between input and output. While revealing its working mechanism both graphically and mathematically, a simple design procedure for such a compact filter is also given. The proposed filter has been implemented in a six-layer ceramic substrate using LTCC technology, showing promising application potentials in miniaturized mobile terminals and Bluetooth RF front-ends. The measured results agree very well with the full-wave electromagnetic designed responses.

Intermodulation distortion and power handling in RF MEMS switches, varactors, and tunable filters

Abstract: This paper presents a theoretical and experimental study of the nonlinear effects generated RF-microelectromechanical system (MEMS) varactors and capacitive switches. The theoretical part includes an analytic derivation, as well as an electromechanical model suitable for computer-aided design (CAD) simulation. The simulations agree very well with measurements performed on a 24-GHz three-pole MEMS tunable filter. It is shown that MEMS capacitive components with a spring constant k>10 N/m generate very low intermodulation, as compared to semiconductor devices, and lead to a two-tone third-order intermodulation intercept point (IIP3) greater than +40 dBm for /spl Delta/f>3-5f/sub 0/, where f/sub 0/ is the mechanical resonant frequency. In fact, the IIP3 increases to +80 dBm for a difference signal (/spl Delta/f) of 5 MHz. The CAD model also allows the evaluation of the power-handling capabilities of the tunable filter and, it is seen that, for the case presented here, distortions become significant for an input power greater than +20 dBm. Noise generation due to thermal effects on a movable membrane (Brownian noise) is also modeled and it is shown that the tunable filter results in a very low phase-noise level close to the carrier.

The Discovery of Two Lyman α Emitters beyond Redshift 6 in the Subaru Deep Field

Abstract: We performed a deep optical imaging survey using a narrow-band filter (NB921) centered at λ=9196 u A together

Image input device

Abstract: An image input apparatus which reconfigures a single reconfigured image from a plurality of low-resolution, object reduced images formed in a specified region on the light detecting element by the micro-lens array, wherein a high-resolution, single reconfigured image can be obtained even if the distance between the subject and the micro-lens array is long (infinitely long, for example), and further a reconfigured image can be realized in colors. The image input apparatus is characterized in that the relative distance between a micro-lens (1a) and light detecting cells (3a) in a specified region, where object reduced images corresponding to the micro-lens (1a) are formed, is different in each micro-lenses (1a). In addition, the light detecting cells (3a) are divided into a plurality of regions, and color filters (primary color filter, or complementary color filter, for example) are disposed in each of the divided regions.

Method and system for extracting cardiac parameters from plethysmographic signals

Abstract: A method and system for extracting cardiac parameters from a plethysmographic signal is described wherein the plethysmographic signal is passed through a first filter to remove non-cardiac components of the signal. A second filter averages a plurality of cardiac cycles and cardiac parameters are extracted from the averaged cardiac signal.

A prescription for transit arrival/departure prediction using automatic vehicle location data

Abstract: In this paper we present a general prescription for the prediction of transit vehicle arrival/departure. The prescription identifies the set of activities that are necessary to preform the prediction task, and describes each activity in a component based framework. We identify the three components, a Tracker, a Filter, and a Predictor, necessary to use automatic vehicle location (AVL) data to position a vehicle in space and time and then predict the arrival/departure at a selected location. Data, starting as an AVL stream, flows through the three components, each component transforms the data, and the end result is a prediction of arrival/departure. The utility of this prescription is that it provides a framework that can be used to describe the steps in any prediction scheme. We describe a Kalman filter for the Filter component, and we present two examples of algorithms that are implemented in the Predictor component. We use these implementations with AVL data to create two examples of transit vehicle prediction systems for the cities of Seattle and Portland.

Texture Segmentation by Multiscale Aggregation of Filter Responses and Shape Elements

Abstract: Texture segmentation is a difficult problem, as is apparentfrom camouflage pictures. A Textured region can containtexture elements of various sizes, each of which can itselfbe textured. We approach this problem using a bottom-upaggregation framework that combines structural characteristicsof texture elements with filter responses. Our processadaptively identifies the shape of texture elements and characterizethem by their size, aspect ratio, orientation, brightness,etc., and then uses various statistics of these propertiesto distinguish between different textures. At the sametime our process uses the statistics of filter responses tocharacterize textures. In our process the shape measuresand the filter responses crosstalk extensively. In addition,a top-down cleaning process is applied to avoid mixing thestatistics of neighboring segments. We tested our algorithmon real images and demonstrate that it can accurately segmentregions that contain challenging textures.

RF bandpass filter design based on CMOS active inductors

Abstract: In this paper, a second-order RF bandpass filter based on active inductor has been implemented in a 0.35 /spl mu/m CMOS process. Issues related to the intrinsic quality factor and dynamic range of the CMOS active inductor are addressed. Tuned at 900 MHz with Q=40, the filter has 28-dB spurious-free-dynamic-range (SFDR) and total current consumption (including buffer stage) is 17 mA with 2.7-V power supply. Experimental results also show the possibility of using them to build higher order RF filter and voltage-controlled oscillator (VCO).

In situ fabricated porous filters for microsystems.

Abstract: Porous filters were fabricated inside a microchannel using emulsion photo-polymerization. The porosity of the filter is dependent on the composition of the pre-polymer mixture. The morphology and flow resistance of four filters with varying water and cross-linker concentrations was studied. The porous filter was used to separate samples, such as whole blood to cell/serum components, based on size. The efficiency of cell/serum separation by the porous filter was tested by performing a glucose-6-phosphate dehydrogenase assay and was found to be comparable to separation by centrifuge. The porous filter thus mimics the functionality of the centrifuge, with the added benefits of no power requirements and ability to handle small sample volumes.

Multi-target particle filtering for the probability hypothesis density

Abstract: When tracking a large number of targets, it is often computationally expensive to represent the full joint distribution over target states. In cases where the targets move independently, each target can instead be tracked with a separate filter. However, this leads to a model-data association problem. Another approach to solve the problem with computational complexity is to track only the first moment of the joint distribution, the probability hypothesis density (PHD). The integral of this distribution over any area S is the expected number of targets within S. Since no record of object identity is kept, the model-data association problem is avoided. The contribution of this paper is a particle filter implementation of the PHD filter mentioned above. This PHD particle filter is applied to tracking of multiple vehicles in terrain, a non-linear tracking problem. Experiments show that the filter can track a changing number of vehicles robustly, achieving near-real-time performance.

A new active common-mode EMI filter for PWM inverter

Abstract: This paper presents a new active common-mode electromagnetic interference (EMI) filter for the pulse-width modulation (PWM) inverter application. The proposed filter is based on the current sensing and compensation circuit and it utilizes a fast transistor amplifier for the current compensation. The amplifier utilizes an isolated low-voltage DC power supply for its biasing and it is possible to construct the active filter independent of the source voltage of the equipment. Thus the proposed active filter can be used in any application regardless of its working voltage. The effectiveness of the proposed circuit has been verified by experimental results.

An Extended Kalman Filter Algorithm for Integrating GPS and Low Cost Dead Reckoning System Data for Vehicle Performance and Emissions Monitoring

Abstract: This paper describes the features of an extended Kalman filter algorithm designed to support the navigational function of a real-time vehicle performance and emissions monitoring system currently under development. The Kalman filter is used to process global positioning system (GPS) data enhanced with dead reckoning (DR) in an integrated mode, to provide continuous positioning in built-up areas. The dynamic model and filter algorithms are discussed in detail, followed by the findings based on computer simulations and a limited field trial carried out in the Greater London area. The results demonstrate that use of the extended Kalman filter algorithm enables the integrated system employing GPS and low cost DR devices to meet the required navigation performance of the device under development.

Cyclical Properties of Baxter-King Filtered Time Series

Abstract: This note demonstrates that the Baxter-King (1999) filter, and in general any bandpass filter, does not isolate the cycle in an unobserved-components model with a stochastic trend. The first differ...

A fully balanced pseudo-differential OTA with common-mode feedforward and inherent common-mode feedback detector

Abstract: A pseudo-differential fully balanced fully symmetric CMOS operational transconductance amplifier (OTA) architecture with inherent common-mode detection is proposed. Through judicious arrangement, the common-mode feedback circuit can be economically implemented. The OTA achieves a third harmonic distortion of -43 dB for 900 mV/sub pp/ at 30 MHz. The OTA, fabricated in 0.5-/spl mu/m CMOS process, is used to design a 100-MHz fourth-order linear phase filter. The measured filter's group delay ripple is 3% for frequencies up to 100 MHz, and the measured dynamic range is 45 dB for a total harmonic distortion of -46 dB. The filter consumes 42.9 mW per complex pole pair while operating from a /spl plusmn/1.65-V power supply.

Guidewire having deployable sheathless protective filter

Abstract: A protective system or apparatus for use in vascular procedures includes a tubular guidewire, a control cable slidable within the tubular guidewire, and a sheathless filter. The control cable is attached to a distal end of the sheathless filter and the tubular guidewire is attached to a proximal end of the sheathless filter. Selective displacement of the control cable radially expands the sheathless filter to create a proximal exterior convex primary filter surface that is positionable downstream from a site of a vascular procedure. The sheathless filter also presents a distal interior concave secondary filter surface. Preferably, the sheathless filter is constructed of a braided wire framework in the form of a tube over which woven polymer fibers or strands are applied to create a filter mesh having a softer filter surface.

An adaptive filter for synchronous extraction of harmonics and distortions

Abstract: This paper provides an adaptive filter for synchronous detection and extraction of harmonics. The filter can be used as integral part of the control system of a power electronic apparatus (e.g., STATCOM, APF, and UPFC) to generate the desired control signals. Stability and convergence analyses of the adaptive filter are presented based on the dynamical systems theory. Performance of the filter is verified as a means for reference signal generation in a shunt active power filter.

A nonlinear set-membership filter for on-line applications

Abstract: A guaranteed estimator for a general class of nonlinear systems and on-line usage is developed and analysed. This filter bounds the linearization error, then applies a linear set-membership filter such that stability guarantees hold for nonlinear systems. A tight bound on the linearization error is found using interval analysis. This filter recursively estimates an ellipsoidal set in which the true state lies. General assumptions include the use of bounded noises and twice continuously differentiable dynamics. When the system is uniformly observable, it is proven that the nonlinear set-membership filter is stable. In addition, if no noise is present and the initial error is small, the error between the centre of the estimated set and the true value converges to zero. The result is an estimator which is computationally attractive and can be implemented robustly in real-time. The proposed method is applied to a two-state example to demonstrate the theoretical results. Copyright © 2003 John Wiley & Sons, Ltd.

A pseudo differential complex filter for Bluetooth with frequency tuning

Abstract: A 12th-order OTA-C complex filter with a nonconventional frequency tuning for a Bluetooth receiver is implemented in a low-cost mainstream 0.35-/spl mu/m CMOS process. This proposed frequency tuning scheme is simpler than the conventional one based on phased-locked loop (PLL). Furthermore, a high-speed pseudo differential OTA using common-mode feedforward (CMFF) and common-mode feedback (CMFB) strategy is proposed. The filter bandwidth is 1 MHz and is centered at 2 MHz. Image and adjacent channels are attenuated by more than 45 and 27 dB, respectively. The integrated input referred noise is 29 /spl mu/V/sub rms/, and the filter chip dissipates 4.7 mA from a 2.7 V supply. The theoretical and experimental results are in good agreement.

Tunable filter, manufacturing method thereof and optical switching device comprising the tunable filter

Abstract: The invention provides a tunable filter that can minimize adjacent channel cross talk despite an increase of a number of available wavelengths and quickly switch a wavelength to be used, and manufacturing method thereof, and also an optical switching device comprising such tunable filter. In a tunable filter having a Fabry-Perot etalon structure, not less than two cavity gaps 114 to 116 are provided and separation between the cavity gaps is controlled by any of electrostatic drive, electromagnetic drive or piezoelectric drive. In this case, the cavity gaps can be formed through the steps of forming a sacrificial layer in advance where a cavity gap is to be formed; forming a plurality of optical multilayer films 100 to 103 ; and removing the sacrificial layer by etching. Substrates 107 and 109 are combined through a supporting column 108.

Beverage cartridge and filter assembly

Abstract: A beverage cartridge comprises a container having a sidewall extending from a first surface and a lip provided at an open end of the container. A cover is coupled to the lip of the container to cover the open end and seal the container. A sloped step is formed in the sidewall and a laminated filter structure is coupled to the sloped step. The laminated filter structure subdivides the container to form a brewing chamber and a beverage receiving chamber. The laminated filter structure includes first and second filter elements, both having edge portions. A seal is provided between the edge portions of the first and the second filter elements. The second filter element has a higher wet strength than the first filter element and the second filter element is located downstream of the first filter element. A beverage powder is contained in the brewing chamber. The container is pierceable to allow injection of liquid into the brewing chamber and to allow prepared beverage to be extracted from the container.