iwarper {SpatialVx}

Image Warping By Hand

Description

Instigate an image warp by selecting control points in the zero- and one-energy images by hand.

Usage

iwarper(x0, x1, nc = 4, labcol = "magenta", 
    col = c("gray", tim.colors(64)), zlim, cex = 2, alwd = 1.25, ...)

Arguments

x0, x1

Numeric matrices giving the zero- and one-energy images. The x1 image is ultimately warped into the x0 image.

nc

integer giving the number of control points to select.

labcol

character describing the color to use when labeling the control points as they are selected.

col

The color scheme to use in plotting the images.

zlim

Range of values for the color scheme in plotting the images.

cex

The usual cex parameter. See the help file for par for more information.

alwd

line width for the arrows added to the deformation plot.

...

Optional arguments to poly.image.

Details

A pair-of-thin-plate-splines image warp mapping is estimated by hand. See Dryden and Mardia (1998) Chapter 10 for more information.

Value

A list object of class “iwarped”

Im0, Im1, Im1.def

The zero- and one-energy images and the deformed one-energy image, resp.

p0, p1

The nc by 2 column matrices of hand-selected zero- and one-energy control points, resp.

warped.locations, s

Two-column matrices giving the entire set of warped locations and original locations, resp.

theta

The matrices defining the image warp, L, iL and B, where the last is the bending energy, and the first two are nc + 3 by nc + 3 matrices describing the control points and inverse control-point matrices.

Author(s)

Eric Gilleland

References

Dryden, I. L. and K. V. Mardia (1998) Statistical Shape Analysis. Wiley, New York, NY, 347pp.

See Also

warper