نتایج جستجو برای: derivative filters

تعداد نتایج: 107307  

ژورنال: فیزیک زمین و فضا 2014
A Afshar GH Norouzi M Abedi V Ardestani, E

This paper describes the application of the so-called normalized standard deviation (NSTD) method to detect edges of gravity anomalies. Using derivative-based methods enhances the anomaly edges, leading to significant improvement of the interpretation of the geological features. There are many methods for enhancing the edges, most of which are high-pass filters based on the horizontal or vertic...

Journal: :IEICE Transactions 2006
Yung-Yi Wang Ying Lu Liang-Cheng Lee

This paper presents a wavelet-based approach for the design of the finite impulse response (FIR) notch filter with controlled null width. The M-band P-regular wavelet filters are employed to constitute the null space of the derivative constraint matrix. Taking advantage of the vanishing moment property of the wavelet filters, the proposed method controls the null width of the notch filter by ad...

2009
Benzerrouk Hamza Ouldali AbdelAziz

The application of the divided derivative filters is described, applied and compared to the most popular tool in estimation , the extended Kalman filter (EKF). In our work the first order divided difference filter and the second order divided difference filter were simulated and applied to integrated navigation system including inertial measurement unit (i) and global positioning system. These ...

Journal: :Computers & Geosciences 2006
Gordon R. J. Cooper Duncan R. Cowan

Measures of the local phase of potential fields can be a useful aid to their interpretation. There are several variations in use, such as the tilt angle, tilt derivative and the Theta map. This paper compares the results of these filters, and introduces some new phase-based filters which show improved performance as edge detectors in different ways. The filters are demonstrated on synthetic gra...

2009
Lewis D. Griffin Martin Lillholm Michael Crosier Justus van Sande

We consider detection of local image symmetry using linear filters. We prove a simple criterion for determining if a filter is sensitive to a group of symmetries. We show that derivative-of-Gaussian (DtG) filters are excellent at detecting local image symmetry. Building on this, we propose a very simple algorithm that, based on the responses of a bank of six DtG filters, classifies each locatio...

1999
Marie Prucha

When conjugate gradient (CG) methods are applied to a problem like velocity transform in 2-D, the principal artifact faced is the half-integration waveform (Claerbout, 1993, 1995). Logically, the best filter to suppress a half-integration waveform is the half-derivative filter. In practice, filters like the half-derivative filter have been reported as causing CG residuals to diverge (Lumley, 19...

Journal: :Neural computation 2011
Miles E. Hansard Radu Horaud

The receptive fields of simple cells in the visual cortex can be understood as linear filters. These filters can be modeled by Gabor functions or gaussian derivatives. Gabor functions can also be combined in an energy model of the complex cell response. This letter proposes an alternative model of the complex cell, based on gaussian derivatives. It is most important to account for the insensiti...

2003
Laiyun Qing Weiqiang Wang Wen Gao

Illumination variation poses a serious problem in video shot detection. It causes false cuts in many shot detection algorithms. A new illumination invariant measure metric is proposed in this paper. The metric is based on the assumption: the outputs of derivative filters to log-illumination are sparse. Thus the outputs of derivative filters to log-image are mainly caused by the scene itself. If...

2010
Alexander Watson Lyudmila Mihaylova Dave Vorley

This paper addresses the problem of bearings only and bearings and extent tracking for closed loop missile guidance systems using particle methods compared with derivative free methods. Lack of observability is a typical phenomenon for the bearings only tracking problem. We demonstrate that exploiting angular extent information does help mitigating the lack of observability issues. The simulati...

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