imager (version 0.31)

vanvliet: Young-Van Vliet recursive Gaussian filter.

Description

The Young-van Vliet filter is a fast approximation to a Gaussian filter (order = 0), or Gaussian derivatives (order = 1 or 2).

Usage

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

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' .

neumann

If true, use Neumann boundary conditions (default false, Dirichlet)

References

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)

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 Young-van Vliet along x")
vanvliet(boats,sigma=2,order=1) %>% plot("First-order Young-van Vliet along x")
vanvliet(boats,sigma=2,order=1) %>% plot("Second-order Young-van Vliet along x")
vanvliet(boats,sigma=2,order=1,axis="y") %>% plot("Second-order Young-van Vliet along y")