uavRst (version 0.5-2)

otbtex_hara: OTB wrapper for Haralick's simple, advanced and higher order texture features.

Description

OTB wrapper for calculating Haralick's simple, advanced and higher order texture features on every pixel in each channel of the input image

Usage

otbtex_hara(x, texture = "all", output_name = "hara",
  path_output = NULL, return_raster = FALSE,
  parameters.xyrad = list(c(1, 1)), parameters.xyoff = list(c(1, 1)),
  parameters.minmax = c(0, 255), parameters.nbbin = 8,
  channel = NULL, verbose = FALSE, giLinks = NULL, ram = "8192")

Arguments

x

A Raster* object or a GeoTiff containing one or more gray value bands

texture

type of filter "all" for all, alternative one of "simple" "advanced" "higher"

output_name

string pattern vor individual naming of the output file(s)

path_output

path outut

return_raster

boolean if TRUE a raster stack is returned

parameters.xyrad

list with the x and y radius in pixel indicating the kernel sizes for which the textures are calculated

parameters.xyoff

vector containg the directional offsets. Valid combinations are: list(c(1,1),c(1,0),c(0,1),c(1,-1))

parameters.minmax

minimum/maximum gray value which can occur.

parameters.nbbin

number of gray level bins (classes)

channel

sequence of bands to be processed

verbose

switch for system messages default is FALSE

giLinks

list. of GI tools cli pathes

ram

reserved memory in MB

Details

More information at: texture tutorial Keep in mind that: Homogeneity is correlated with Contrast, r = -0.80 Homogeneity is correlated with Dissimilarity, r = -0.95 GLCM Variance is correlated with Contrast, r= 0.89 GLCM Variance is correlated with Dissimilarity, r= 0.91 GLCM Variance is correlated with Homogeneity, r= -0.83 Entropy is correlated with ASM, r= -0.87 GLCM Mean and Correlation are more independent. For the same image, GLCM Mean shows r< 0.1 with any of the other texture measures demonstrated in this tutorial. GLCM Correlation shows r<0.5 with any other measure. for a review of a lot of feature extraction algorithms look at: Williams et al, 2012, J. of Electronic Imaging, 21(2), 023016 (2012) glcm <-> haralick "mean" <-> "advanced 1", "variance" <-> "advanced 2", "homogeneity" <-> "simple 4", "contrast"<-> "simple 5", "dissimilarity" <-> "advanced 2", "entropy" <-> "simple 2", "second_moment"<-> "simple 4", "correlation" <-> "simple 3" Furthermore using stats will cover mean and variance while dissimilarity is highly correlated to homogeneity data.

References

Haralick, R.M., K. Shanmugam and I. Dinstein. 1973. Textural Features for Image Classification. IEEE Transactions on Systems, Man and Cybernetics. SMC-3(6):610-620. Orfeo Toolbox Sofware Guide, 2016 "simple": computes the following 8 local Haralick textures features: Energy, Entropy, Correlation, Inverse Difference Moment, Inertia, Cluster Shade, Cluster Prominence and Haralick Correlation. They are provided in this exact order in the output image. Thus, this application computes the following Haralick textures over a neighborhood with user defined radius. To improve the speed of computation, a variant of Grey Level Co-occurrence Matrix(GLCM) called Grey Level Co-occurrence Indexed List (GLCIL) is used. Given below is the mathematical explanation on the computation of each textures. Here g( i,j) is the frequency of element in the GLCIL whose index is i,j. GLCIL stores a pair of frequency of two pixels from the given offset and the cell index (i,j) of the pixel in the neighborhood window. Where each element in GLCIL is a pair of pixel index and it's frequency, g(i,j) is the frequency value of the pair having index is i,j. Energy Entropy Correlation Inertia (contrast) Cluster Shade Cluster Prominence Haralick's Correlation "advanced": computes the following 10 texture features: Mean, Variance, Dissimilarity, Sum Average, Sum Variance, Sum Entropy, Difference of Entropies, Difference of Variances, IC1 and IC2. They are provided in this exact order in the output image. The textures are computed over a sliding window with user defined radius. To improve the speed of computation, a variant of Grey Level Co-occurrence Matrix(GLCM) called Grey Level Co-occurrence Indexed List (GLCIL) is used. Given below is the mathematical explanation on the computation of each textures. Here g( i,j) is the frequency of element in the GLCIL whose index is i,j. GLCIL stores a pair of frequency of two pixels from the given offset and the cell index ( i,j) of the pixel in the neighborhood window. (where each element in GLCIL is a pair of pixel index and it's frequency, g( i,j) is the frequency value of the pair having index is i,j.

Mean Sum of squares: Variance Dissimilarity Sum average Sum Variance Sum Entropy Difference variance Difference entropy Information Measures of Correlation IC1 Information Measures of Correlation IC2

"higher": computes 11 local higher order statistics textures coefficients based on the grey level run-length matrix. It computes the following Haralick textures over a sliding window with user defined radius: (where p( i,j) is the element in cell i,j of a normalized Run Length Matrix (n_r) is the total number of runs and n_p is the total number of pixels ):

Short Run Emphasis Long Run Emphasis Grey-Level Nonuniformity Run Length Nonuniformity Low Grey-Level Run Emphasis High Grey-Level Run Emphasis Short Run Low Grey-Level Emphasis Short Run High Grey-Level Emphasis Long Run Low Grey-Level Emphasis Long Run High Grey-Level Emphasis

Examples

# NOT RUN {
require(uavRst)
require(link2GI)
## -check if OTB is installed correctly
giLinks <- uavRst::linkAll()
if (giLinks$otb$exist) {
setwd(tempdir())
##- get some typical data as provided by the authority
tmp<-Sys.setlocale('LC_ALL','C')
utils::download.file(url="http://www.ldbv.bayern.de/file/zip/5619/DOP%2040_CIR.zip",
                     destfile="testdata.zip")
unzip("testdata.zip",junkpaths = TRUE,overwrite = TRUE)

# calculate simple Haralick-textures
r<- otbtex_hara(x="4490600_5321400.tif",texture = "simple",return_raster = TRUE)

#plot the results :
##- visualize all layers
raster::plot(r)
tmp<-Sys.setlocale(category = "LC_ALL", locale = "de_DE.-8")
}
# }