laplace_beltrami_smoothing: Smoothing on manifold

In Mouse-Imaging-Centre/RMINC: Statistical Tools for Medical Imaging NetCDF (MINC) Files

Smoothing on manifold

Description

Smoothing scalar field on a triangle-mesh manifold

Usage

laplace_beltrami_smoothing(manifold, scalar_field, fwhm, maxiter = 1000)

Arguments

manifold	A list of length 2 with names 'vertex_matrix' and 'triangle_matrix' like bic_obj object produced by read_obj
scalar_field	a vector whose elements are values of the field at each manifold vertex
fwhm	the degree of smoothing. It represents the full-width-half-maximum of the blurring kernel if the manifold had no curvature. Regardless of curvature, higher the fwhm, the greater the amount of smoothing.
maxiter	int specifying the maximum number of iterations for the algorithm

Value

a vector whose elements are values of the smoothed field at each manifold vertex

Examples

## Not run: 
# Load an object
manifold =
  read_obj(
    file.path("/axiom2/projects/software/cortical-thickness/",
              "MWM/c57bl6_laplacian_grid_full_surface_simplified.obj"))

# Compute the laplace beltrami operator and attach it to the manifold
#  not necessary but will make future smoothing computations on the same manifold faster
manifold$laplace_beltrami_operator = laplace_beltrami_operator(manifold)

# Generate some random uniform vertex data
init_stats = runif(ncol(manifold$vertex_matrix))

# Smooth the stats on the manifold
smooth_stats = laplace_beltrami_smoothing(manifold,init_stats,0.2)

# Plot results
plot(manifold, init_stats, colour_range = c(.5,1))
plot(manifold, smooth_stats, colour_range = c(.5,1))

## End(Not run)

Mouse-Imaging-Centre/RMINC documentation built on Nov. 12, 2022, 1:50 p.m.