Search results for "Linear filter"

A fast recursive algorithm to compute local axial moments

2001

The paper describes a fast algorithm to compute local axial moments used in the algorithm of discrete symmetry transform (DST). The basic idea is grounded on fast recursive implementation of respective linear filters by using the so-called primitive kernel functions since the moment computation can be performed in the framework of linear filtering. The main result is that the computation of the local axial moments is independent of the kernel size, i.e. of the order O(1) per data point (pixel). This result is of relevance whenever the DST is used to face with real time computer vision problems. The experimental results confirm the time complexity predicted by the theory.

LabVIEW modeling and simulation, of the digital filters

2015

In order to study digital filters using virtual instrumentation a simulation program specifically designed for this purpose has been developed. To implement this program means to use the following facilities: studying digital Butterworth filters, Cebyshev, Bessel and Median and change their parameters: bandwidth, order, rank and slope; possibility of changing the input parameters: amplitude, offset and frequency; overlay over the input signal, to one of the types of noise such as white noise, Gaussian white noise and Poisson noise; choosing a type of digital filters: low pass, high pass, band-pass and band stop; waveforms graphical representation of the input and output signals; graphical r…

Pattern dynamics in a nonlinear electrical lattice

2003

International audience; In this paper, we present experiments using a nonlinear electrical line, modeling the FitzHugh-Nagumo equation, without recovery term. Different patterns are studied according to the para meters of this medium and initial conditions. We then propose to apply these results to the domain of signal processing. We show that erosion and dilation of a binary signal, two kinds,of binarization-one depending on an amplitude threshold, the other on an energetical threshold-and nonlinear filtering allowing noise removal can be obtained in the same medium.

Nonlinear morphological correlation: optoelectronic implementation

2008

An optoelectronic implementation of the nonlinear morphological correlation by use of a threshold-decomposition technique and a joint transform correlator architecture is presented. This nonlinear morphological correlation provides improved image detection compared with standard linear optical pattern-recognition correlation methods. It also offers a more robust detection of low-intensity images in the presence of high-intensity patterns to be rejected.

A linear matrix inequality approach to robust fault detection filter design of linear systems with mixed time-varying delays and nonlinear perturbati…

2010

Accepted version of an article in the journal: Journal of the Franklin Institute-Engineering and Applied Mathematics. The definitive version can be found on Sciverse: http://dx.doi.org/10.1016/j.jfranklin.2010.03.004 In this paper, the problem of robust fault detection filter (RFDF) design for a class of linear systems with some nonlinear perturbations and mixed neutral and discrete time-varying delays is investigated. By using a descriptor technique, Lyapunov-Krasovskii functional and a suitable change of variables, new required sufficient conditions are established in terms of delay-dependent linear matrix inequalities (LMIs) to synthesize the residual generation scheme. Based on the Luen…

FDTD signal extrapolation using a finite impulse response neural network model

1999

Intensity invariant nonlinear correlation filtering in spatially disjoint noise.

2010

We analyze the performance of a nonlinear correlation called the Locally Adaptive Contrast Invariant Filter in the presence of spatially disjoint noise under the peak-to-sidelobe ratio (PSR) metric. We show that the PSR using the nonlinear correlation improves as the disjoint noise intensity increases, whereas, for common linear filtering, it goes to zero. Experimental results as well as comparisons with a classical matched filter are given.

Real And Positive Filter Based On Circular Harmonic Expansion

1989

A real and positive filter for pattern recognition is presented. The filter, based on the circular harmonic (CH) expansion of a real function, is partially rotation invariant. As it is real and positive, the filter can be recorded on a transparency as an amplitude filter. Computer simulations of character recognition show a partial rotation invariance of about 40°. Optical experiments agree with these results and with acceptable discrimination between different characters. Nevertheless, due to experimental difficulties, the method is onerous for use in general pattern recognition problems.