نتایج جستجو برای: spatial derivatives

تعداد نتایج: 465248  

Journal: :Biological & pharmaceutical bulletin 2000
H Takahashi T Ishioka Y Koiso M Sodeoka Y Hashimoto

Substituted phenylazo and phenylazoxy compounds were systematically prepared and their anti-androgenic activity was measured in terms of (1) the growth-inhibiting effect on an androgen-dependent cell line, SC-3, and (2) the binding affinity to nuclear androgen receptor. Generally, azo/azoxy compounds showed cell toxicity, and the growth-inhibiting effects on SC-3 cells correlated with the toxic...

2006
Dheeraj Singaraju René Vidal

We propose a closed form solution for segmenting mixtures of 2-D translational and 2-D affine motion models directly from the image intensities. Our approach exploits the fact that the spatial-temporal image derivatives generated by a mixture of these motion models must satisfy a bi-homogeneous polynomial called the multibody brightness constancy constraint (MBCC). We show that the degrees of t...

2004
Samuel T. Thurman James R. Fienup

Fourier transform imaging spectroscopy can be performed with a segmented-aperture telescope or a multiple-telescope array using the subaperture piston control mechanisms. Spectrum recovery from intensity measurements is analyzed for a general aperture configuration. The spatial transfer functions of the recovered spectral images are shown to vanish necessarily at the DC spatial frequency. This ...

2009
Jesús Angulo

Colour image representation using real quaternions has shown to be very useful for linear and morphological colour filtering. This paper deals with the extension of first derivatives-based structure tensor for various quaternionic colour image representations. Classical corner and edge features are obtained from eigenvalues of the quaternionic colour structure tensors. We study the properties o...

2015
José A. Romero Gerardo Aguirre Hernández Sylvain Bernès

The title trihalogenated nitro-benzene derivatives, C6H2Br3NO2 and C6H2Br2INO2, crystallize in triclinic and monoclinic cells, respectively, with two mol-ecules per asymmetric unit in each case. The asymmetric unit of the tri-bromo compound features a polarized Br(δ+)⋯Br(δ-) inter-molecular halogen bond. After substitution of the Br atom in the para position with respect to the nitro group, the...

Journal: :IEEE Trans. Pattern Anal. Mach. Intell. 1997
César Silva José Santos-Victor

We address the problem of egomotion estimation for a monocular observer moving under arbitrary translation and rotation, in an unknown environment. The method we propose is uniquely based on the spatio-temporal image derivatives, or the normal ow. We introduce a search paradigm which is based on geometric properties of the normal ow eld, and consists in considering a family of search subspaces ...

Journal: :Perception & psychophysics 1998
V J Perotti J T Todd J S Lappin F Phillips

Observers viewed the optical flow field of a rotating quadric surface patch and were required to match its perceived structure by adjusting the shape of a stereoscopically presented surface. In Experiment 1, the flow fields included rigid object rotations and constant flow fields with patterns of image acceleration that had no possible rigid interpretation. In performing their matches, observer...

Journal: :Journal of King Saud University - Science 2021

This paper adopts an efficient meshless approach for approximating the nonlinear fractional fourth-order diffusion model described in Riemann–Liouville sense. A second-order difference technique is applied to discretize temporal derivatives, while radial basis function generated finite scheme approximates spatial derivatives. One key advantage of local collocation method approximation derivativ...

Journal: :journal of arthropod-borne diseases 0
viviane barros silva medicinal chemistry laboratory, pharmacy department, federal university of sergipe, são cristóvão, brazil daniele lima travassos medicinal chemistry laboratory, pharmacy department, federal university of sergipe, são cristóvão, brazil angelita nepel nuclear magnetic resonance laboratory, chemistry department, federal university of paraná, curitiba, brazil andersson barison nuclear magnetic resonance laboratory, chemistry department, federal university of paraná, curitiba, brazil emmanoel vilaça costa chemistry department, institute of sciences, federal university of amazonas, manaus, brazil luciana scotti biotechnology center, federal university of paraíba, campus i, joão pessoa, brazil

background : thymol and carvacrol have previously demonstrated larvicidal activity against aedes aegypti (diptera: culicidae). in view of this fact, it was of our interest to obtain synthetic derivatives and evaluate their larvicidal ac­tivity on ae. aegypti larvae. methods : structural modifications were performed on thymol and carvacrol in an effort to understand the functional groups necessa...

Journal: :International journal for numerical methods in biomedical engineering 2015
A M Gambaruto

The spatial derivatives of the image intensity provide topographic information that may be used to identify and segment objects. The accurate computation of the derivatives is often hampered in medical images by the presence of noise and a limited resolution. This paper focuses on accurate computation of spatial derivatives and their subsequent use to process an image gradient field directly, f...

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