calcHOM: HOM Homogeinity
In RTextureMetrics: Functions for calculation of texture metrics for Grey Level Co-occurrence Matrices

Description Usage Arguments Details Value Author(s) References See Also Examples

View source: R/calcHOM.R

calculates HOMOGENEITY measure for Grey Level co-occurrence matrices

1	calcHOM(rawmat)

rawmat

assigns the GLC-Matrix to use

Homogeneity weigths values by the inverse of the Contrast weight with weights decreasing exponentially away from diagonal Homogeneity measure is sometimes also called 'Inverse Difference Moment'.

returns Homogeneity value

H.-J. Klemmt

Toennies, D., 2005: Grundlagen der Bildverabeitung, 341 S., Pearson Studium Harralick, R.M., Shanmugam, K., Dinstein, I., 1973: Textural Features for image classification. IEEE Transactions on Systems, Man and Cybernetics, SMC vol. 3 no. 6, pp. 610-620.

GLCM Tutorial by Mryka-Hall-Beyer, http://www.fp.ucalgary.ca/mhallbey/homogeneity.htm

data<-c(0,0,1,1,0,0,1,1,0,2,2,2,2,2,3,3)
mat<-matrix(data, nrow=4, byrow=TRUE)
(mat)
GLCM<-genGLCM(2,1,mat)
(GLCM)
(calcHOM(GLCM))
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function (rawmat) 
{
    size <- dim(rawmat)[1]
    mathomweights <- matrix(0, nrow = size, ncol = size)
    for (i in 1:size) {
        for (a in 1:size) {
            mathomweights[i, a] <- 1/(1 + (a - i)^2)
        }
    }
    hom <- rawmat * mathomweights
    return(sum(hom))
  }