Generic Filter Research Articles

Multiple object detection and tracking with pseudo-particle filter

To tackle the divergence of the classical particle filter method for multiple object tracking in image sequences, a new particle filter, called pseudoparticle filter (PPF), is proposed. The PPF invokes subset particles of generic particle filters to form a continuous estimate of the posterior density function of the objects. After sampling-importance resampling (SIR), the subset particles converge to the observations. It is proved that, using an appropriate kernel function of the mean shift algorithm, we can get the subset particles of the observations and the fixed points of clustering results as the state of the objects. A multiple object data association and state estimation technique is proposed to resolve the subset particles correspondence ambiguities that arise when multiple objects are present. Experimental results demonstrate the efficiency and effectiveness of the algorithm for single and multiple object tracking.

Dynamic filter merging and mergeability detection for publish/subscribe

Filter-based publish/subscribe and content-based routing have been proposed for flexible information dissemination in distributed environments. A content-based router is part of an overlay structure, in which each router forwards events to neighbouring routers and local clients based on their interests. Filter merging or summarization has been proposed as an optimization strategy in this environment. These techniques combine filters to reduce the number of propagated filters and thus the size of distributed state. In this paper, we present the algorithms for generic dynamic filter merging and filter mergeability detection, and discuss integration with routing tables. The algorithms are based on a formal framework of merging rules. Experimental results are examined and analyzed for both desktop systems and small devices. The results indicate that dynamic filter merging is feasible given that the workload is mergeable.

Efficient contour detection in binary and label images

ly in ITK, the only way to find the contour of the objects in a binary image is to use the BinaryErodeImageFilter, with a kernel of radius 1. This filter is a generic filter, made to support any shape and size of structuring element, and thus is not optimized for the particular case needed to detect the contours. Moreover, that filter is not multithreaded, so it can’t get the performance improvements allowed by the multiprocessor systems. As a result, the contour detection can be quite time consuming currently – for example, in SignedMaurerDistanceMapImageFilter, the contour detection takes about 33% of the execution time. This contribution comes with a new filter which highly improve the performance of the contour detection in the binary image, and a second filter which allow the detection of the countours in label images with similar performance.

COSTA a problem solving environment for data assimilation applied for hydrodynamical modelling

A problem solving environment for data assimilation called COSTA is developed at Delft University of Technology. The goal of COSTA is to offer a modular framework where simulation models can be combined with various data assimilation methods. COSTA defines a number of building blocks called components. Examples of components are model, method, stochastic observer and state-vector. New data assimilation systems can be created by combining these components. This paper describes the application of COSTA to the WAQUA/TRIWAQ shallow water simulation model. In the past a model specific RRSQRT Kalman filter has been implemented for WAQUA/TRIWAQ. However, this implementation cannot be used in combination with other models. The WAQUA/TRIWAQ model is changed into a COSTA model component and the original RRSQRT Kalman filter is changed into a generic filter that can be used for other models as well. The new filter is now a part of the COSTA environment. The original filter contained a number of WAQUA/TRIWAQ specific aspects e.g. the drying and flooding of areas in the model. These model specific issues are identified, isolated and moved into the model component. A COSTA based implementation of WAQUA/TRIWAQ with the RRSQRT Kalman filter is realized and compared to the original system in a number of experiments. The experiments show that the COSTA based system produces the correct results and the computational overhead for using COSTA is low. The new RRSQRT Kalman filter is also combined with other COSTA models including the LOTOS-EUROS model for atmospherical transport, chemistry (chemical reaction) and deposition of air pollution on the scale of Europe.

CFA‐based grounded‐capacitor operational simulation of ladder filters

AbstractA systematic method for deriving CFA‐based all‐grounded‐capacitor filters from current mode RLC prototype ladder has been given. It is based on the operational simulation of node voltages and branch currents. It is extended to a voltage‐mode ladder. These filters employ a minimum number of capacitors and minimum total capacitance. In some cases, all the capacitors can be made of equal value. Such filters are suitable for fabrication in integrated circuit technology. Illustrative examples for realizing generic filters are included with their simulation results. Copyright © 2007 John Wiley & Sons, Ltd.

A Multi-Sensor Navigation Filter for High Accuracy Positioning in all Environments

The aim of the SPACE project is to develop a mobile test bed that can position to within centimetres in all conditions and environments. To achieve this goal, a number of different positioning technologies have to be integrated together including GNSS, INS, pseudolites and other technologies such as Ultra Wideband and Bluetooth ranging. The integration of these sensors is achieved by the development of a ‘plug and play’ filter that will optimally combine measurements from each sensor to form an accurate position solution. The filter has been designed so that the sensors are integrated at the measurement level wherever possible, so partial measurements from different systems can be used together.This paper describes the development of the plug and play filter, focussing in particular on how the states are defined, how the measurements are used, and how a generic filter can be developed that can integrate all types of positioning sensor. Some early results from the filter are shown integrating GPS, INS and simulated measurements from an Ultra Wideband system. A prototype version of the mobile test bed is also described.

Prikry on extenders, revisited

The extender based forcing of Gitik and Magidor is generalized to yield, given any extender j: V a M with critical point κ, a cardinal preserving generic extension with no new bounded subset of κ in which cf(κ) = ω and $$\kappa ^\omega = |j(\kappa )|$$ . Assuming a superstrong cardinal exists, the forcing notion is used to construct a model in which the added Prikry sequences are a scale in the normal Prikry sequence. In addition, several ways to produce generic filter over an iterated ultrapower are presented.

A unified framework for adaptive filter algorithms with variable step-size

Employing a recently introduced framework within which a large number of classical and modern adaptive filter algorithms can be viewed as special cases, we extend this framework to cover block normalized LMS (BNLMS) and normalized data reusing LMS (NDRLMS) adaptive filter algorithms. Accordingly, we develop a generic variable step-size adaptive filter. Variable step-size normalized LMS (VSSNLMS) and VSS affine projection algorithms (VSSAPA) are particular examples of adaptive algorithms covered by this generic variable step-size adaptive filter. In this paper we introduce two new VSS adaptive filter algorithms named the variable step-size BNLMS (VSSBNLMS) and the variable step-size NDRLMS (VSSNDRLMS) based on the generic VSS adaptive filter. The proposed algorithms show the higher convergence rate and lower steady-state mean square error compared to the ordinary BNLMS and NDRLMS algorithms.

Universal forcing notions and ideals

Our main result states that a finite iteration of Universal Meager forcing notions adds generic filters for many forcing notions determined by universality parameters. We also give some results concerning cardinal characteristics of the σ-ideals determined by those universality parameters.

Novel Roughening Method for Reentry Vehicle Tracking Using Particle Filter

An improvement for the generic particle filter (PF) is to add a roughening step in resampling. This paper studied the reentry vehicle tracking problem using PF with roughening. A novel algorithm to calculate the reasonable standard deviation of the roughening jitter is proposed. For comparison, the Unscented Kalman filter, the generic PF and the PF with the typical roughening are used to gauge the estimation performance, and the results favor the PF with the proposed roughening method. The generic PF and the PF with the typical roughening have low probabilities of success under conditions of comparatively large initialization bias and accurate radar measurement. The proposed PF can handle these cases efficiently and give better performance.

Hidden variables in quantum mechanics: Generic models, set-theoretic forcing, and the appearance of probability

The hidden-variables premise is shown to be equivalent to the existence of generic filters for systems of commuting observables of a quantum system. The significance of this equivalence is interpreted in light of the theory of generic filters and boolean-valued models in set theory. The apparent stochastic nature of quantum observation is derived for these hidden-variables models.

Dense subtrees in complete Boolean algebras

AbstractWe characterize complete Boolean algebras with dense subtrees. The main results show that a complete Boolean algebra contains a dense tree if its generic filter collapses the algebra's density to its distributivity number and the reverse holds for homogeneous algebras. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Forcing under Anti‐Foundation Axiom: An expression of the stalks

AbstractWe introduce a new simple way of defining the forcing method that works well in the usual setting under FA, the Foundation Axiom, and moreover works even under Aczel's AFA, the Anti‐Foundation Axiom. This new way allows us to have an intuition about what happens in defining the forcing relation. The main tool is H. Friedman's method of defining the extensional membership relation ∈ by means of the intensional membership relation ε .Analogously to the usual forcing and the usual generic extension for FA‐models, we can justify the existence of generic filters and can obtain the Forcing Theorem and the Minimal Model Theorem with some modifications. These results are on the line of works to investigate whether model theory for AFA‐set theory can be developed in a similar way to that for FA‐set theory.Aczel pointed out that the quotient of transition systems by the largest bisimulation and transition relations have the essentially same theory as the set theory with AFA. Therefore, we could hope that, by using our new method, some open problems about transition systems turn out to be consistent or independent. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

A new mixed mode biquad using reduced number of active and passive elements

The configuration that can work in mixed mode may be useful from IC realization viewpoint and application adaptability. This paper proposes a generalized mixed mode universal filter configuration that may be used in all possible modes i.e. voltage mode, current mode, trans-impedance mode and trans-admittance mode. The architecture uses minimum number of active and passive components reported till date and can realize all generic filter functions: low pass, band pass, high pass, notch and all pass. PSPICE simulation results agree well with experimental values.

On the Design of Filters for Gradient-Based Motion Estimation

Gradient based approaches in motion estimation (Optical-Flow) refer to those techniques that estimate the motion of an image sequence based on local derivatives in the image intensity. In order to best evaluate local changes, specific filters are applied to the image sequence. These filters are typically composed of a spatiotemporal pre-smoothing filter followed by discrete derivative ones. The design of these filters plays an important role in the estimation accuracy. This paper proposes a method for such a design. Unlike previous methods that consider these filters as optimized approximations for continuum derivatives, the proposed design procedure defines the optimality directly with respect to the motion estimation goal. One possible result of the suggested scheme is a set of image dependent filters that can be computed prior to the estimation process. An alternative interpretation is the creation of generic filters, capable of treating natural images. Simulations demonstrate the validity of the new design approach.

Generic and customised digital image enhancement filters for the visually impaired

This study compares the effectiveness of various image enhancement filters for improving the perceived visibility of coloured digital natural images for people with visual impairment. Generic filters were compared with Peli’s adaptive enhancement and adaptive thresholding and custom-devised filters based on each subject’s contrast sensitivity loss. Subjects with low vision made within filter rankings followed by between filter ratings. In general, subjects preferred filters with lower gains. Unsharp masking resulted in a significant increase in perceived visibility for some image types ( p ⩽ 0.05) while Peli’s adaptive enhancement, edge enhancement and histogram equalization resulted in borderline improvements. Adaptive thresholding and the custom devised filter did not result in overall improvements in perceived visibility.

Novel mixed-mode universal biquad configuration

Although a variety of CFOA-based biquads have been known in the literature, any CFOA-based circuit capable of realising universal biquad filters in all the four possible modes i.e. voltage-mode, current-mode, trans-admittance-mode and trans-impedance-mode, has not been reported in the literature so far. In this paper, a novel configuration has been presented, which realises all the five generic filter functions (namely, low-pass, band-pass, high-pass, notch and all-pass) from the same circuit in all the four possible modes, employing only four-Current feedback operational amplifiers (CFOA) along with two grounded-capacitors as desirable for Integrated Circuit implementation. The workability of the circuit has been confirmed by hardware implementation based on AD844 type CFOAs.

On the Realization of Universal Current Mode Biquads Using a Single CFOA

The four terminal Current feedback op-amps (CFOA) with an external compensation pin, such as AD844, have received prominent attention during the past decade as alternative building blocks for analog circuit design because of their significant advantages over the traditional voltage-mode op-amp (VOA). A popular application of CFOAs has been in realizing voltage-mode (VM) and current-mode (CM) biquad filters. Previously known universal CM biquads (i.e. those capable of realizing all the five generic filter functions namely, low-pass, band-pass, high-pass, notch and all-pass) realizable with CFOAs require two to nine CFOAs. Although a few dual-function/three-function single-CFOA-based CM circuits have appeared in literature, no single-CFOA-based canonic universal CM biquad with explicit CM output has been reported in the literature up until now. This paper fills this void by presenting a set of eight minimal universal CM biquads all of which are realizable with only a single CFOA. The non-ideal analysis of the proposed circuits has been presented, their comparative features, advantages and limitations have been brought out. The workability of all the proposed circuits has been confirmed by PSPICE simulations and experimental results based upon AD844 type CFOAs.

Universal current mode biquad using a single CFOA

Because of their several advantages over the traditional voltage mode op-amp, current feedback op-amps (CFOAs) have attracted prominent attention as alternative building blocks for biquad filter realization. Previously known universal current mode (CM) biquads (i.e. those capable of realizing all five generic filter functions, namely low-pass, band-pass, high-pass, notch and all-pass) are realizable with CFOAs but require two to nine CFOAs. Although a few dual-function/three-function single-CFOA-based CM circuits have appeared in the literature, no single-CFOA-based canonic universal CM biquad with explicit CM output has been reported until now. This paper presents such a circuit. The workability of the proposed circuit has been confirmed by PSPICE simulations based upon AD844-type CFOAs.

Analytical synthesis of current-mode high-order ota-c filters

This work presents a new general synthesis method for high-order current-mode OTA-C (operational transconductance amplifiers and capacitor) filters. The method is based on the analytical solution of a single, nth-order generic filter transfer function and the generation of n number of realizable transfer functions implemented using lossless integrators. The method provides systematic synthesis approach to high-order OTA-C filters. Furthermore, the method generates circuits that are optimal in terms of components count and without trading off any of the VLSI features of OTA-C filters. Simulation results are included validating the synthesis method.