imager (version 0.14)

vanvliet: Van Vliet recursive Gaussian filter.

Description

From: I.T. Young, L.J. van Vliet, M. van Ginkel, Recursive Gabor filtering. IEEE Trans. Sig. Proc., vol. 50, pp. 2799-2805, 2002. (this is an improvement over Young-Van Vliet, Sig. Proc. 44, 1995)

Usage

vanvliet(im, sigma, order = 0L, axis = "x", boundary_conditions = 0L)

Arguments

im

an image

sigma

standard deviation of the Gaussian filter

order

the order of the filter 0,1,2,3

axis

Axis along which the filter is computed. Can be { 'x' | 'y' | 'z' | 'c' }.

boundary_conditions

Boundary conditions. Can be { 0=dirichlet | 1=neumann }. (Dirichlet boundary condition has a strange behavior)

Details

Boundary conditions (only for order 0) using Triggs matrix, from B. Triggs and M. Sdika. Boundary conditions for Young-van Vliet recursive filtering. IEEE Trans. Signal Processing, vol. 54, pp. 2365-2367, 2006.

Examples

vanvliet(boats,sigma=2,order=0) %>% plot("Zeroth-order Vanvliet along x")
vanvliet(boats,sigma=2,order=1) %>% plot("First-order Vanvliet along x")
vanvliet(boats,sigma=2,order=1) %>% plot("Second-order Vanvliet along x")
vanvliet(boats,sigma=2,order=1,axis="y") %>% plot("Second-order Vanvliet along y")