Marcos S. Amaral

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The estimation of derivatives is an important and sensitive task in digital image processing and analysis, both accuracy and computational efficiency being expected of a differential operator. Here we propose a new filter—designed through a strategy based on the Green’s function of a signal matching equation—that responds to such demands. When used for edge(More)
Green's functions are a traditional technique for solving inhomogeneous differential equations which has found several applications in pure and applied science, as, for instance, in Electrodynamics or Quantum Mechanics (Hassani, 2002). Given a one-dimensional linear differential operator, x , and a set of boundary conditions, the solution to the(More)
We propose and analyze a model, based on signal-tuned Gabor functions, for the receptive fields and responses of V1 cells. Signal-tuned Gabor functions are gaussian-modulated sinusoids whose parameters are obtained from a given, spatial, or spectral "tuning" signal. These functions can be proven to yield exact representations of their tuning signals and(More)
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