Kernel smoothing on a 1D, 2D or 3D grid

Performs Kernel smoothing on a 1D, 2D or 3D grid by fft

kernsm(y, h = 1, kern = "Gaussian", m = 0, nsector = 1, sector = 1,
       symmetric = FALSE, unit = c("SD","FWHM"))

Arguments

y	Object of class `"array"` containing the original (response) data on a grid
h	bandwidth
kern	Determines the kernel function. Object of class `"character"` kernel, can be any of `c("Gaussian","Uniform","Triangle","Epanechnicov","Biweight","Triweight")`. Defaults to `kern="Gaussian"`
m	Object of class `"integer"` vector of length `length(dy)` determining the order of derivatives specified for the coordinate directios.
nsector	number of sectors to use. Positive weights are restricted to the sector selected by `sector`
sector	Object of class `"integer"` between `1` and `nsector`. sector used.
symmetric	Object of class `"logical"` determines if sectors are symmetric with respect to the origin.
unit	How should the bandwidth be interpreted in case of a Gaussian kernel. For `"SD"` the bandwidth refers to the standard deviation of the kernel while `"FWHM"` interprets the banwidth in terms of Full Width Half Maximum of the kernel.

Details

In case of any(m>0) derivative kernels are generated and applied for the corresponding coordinate directions. If nsector>1 the support of the kernel is restricted to a circular sector determined by sector.

Value

An object of class kernsm

References

Local Approximation Techniques in Signal And Image Processing, SPIE Society of Photo-Optical Instrumentation Engin., 2006, PM157

Author