Performs a low, high, or bandpass Gaussian filter on a surface matrix with a particular cut-off wavelength.

preProcess_gaussFilter(x3p, wavelength = c(16, 500), filtertype = "bp")

## Arguments

x3p

an x3p object containing a surface matrix

wavelength

cut-off wavelength

filtertype

specifies whether a low pass, "lp", high pass, "hp", or bandpass, "bp" filter is to be used. Note that setting filterype = "bp" means that wavelength should be a vector of two numbers. In this case, the max of these two number will be used for the high pass filter and the min for the low pass filter.

## Value

An x3p object containing the Gaussian-filtered surface matrix.

https://www.mathworks.com/matlabcentral/fileexchange/61003-filt2-2d-geospatial-data-filter?focused=7181587&tab=example

## Examples

data(fadul1.1_processed)

#  been Gaussian filtered)
#> x3p object
#> Instrument: NanoFocus
#> size (width x height): 545 x 545 in pixel
#> resolution: 6.2500e-06 x 6.2500e-06
#> Creator: Xiaoyu Zheng
#> Comment: NA: 0.30

#As a part of the recommended preprocessing pipeline (take > 5 sec to run):
if (FALSE) {

region = "exterior",

region = "interior",

statistic = "quantile",
tau = .5,
method = "fn")