R/Conte.r

In Arothron/ctrlR: Functions used in my PhD thesis

#' Conte
#' 
#' Function from the Morphemetric with R
#' @author Jean Claude
#' @export

Conte<-function(x, imagematrix){
I<-imagematrix
x<-rev(x)
x[1]<-dim(I)[1]-x[1]
while (abs(I[x[1],x[2]]-I[x[1],(x[2]-1)])<0.1){x[2]<-x[2]-1}
a<-1
M<-matrix(c(0,-1,-1,-1,0,1,1,1,1,1,0,-1,-1,-1,0,1),
2,8,byrow=T)
M<-cbind(M[,8],M,M[,1]) 
X<-0; Y<-0;
x1<-x[1]; x2<-x[2]
SS<-NA; S<-6
while ((any(c(X[a],Y[a])!=c(x1,x2) ) | length(X)<3))
 {if (abs(I[x[1]+M[1,S+1],x[2]+M[2,S+1]]-I[x[1],x[2]])<0.1)
{a<-a+1;X[a]<-x[1];Y[a]<-x[2];x<-x+M[,S+1]
 SS[a]<-S+1; S<-(S+7)%%8}
 else if (abs(I[x[1]+M[1,S+2],x[2]+M[2,S+2]]
 -I[x[1],x[2]])<0.1)
{a<-a+1;X[a]<-x[1];Y[a]<-x[2];x<-x+M[,S+2]
 SS[a]<-S+2; S<-(S+7)%%8}
 else if (abs(I[x[1]+M[1,(S+3)],x[2]+M[2,(S+3)]]
 -I[x[1],x[2]])<0.1)
 {a<-a+1;X[a]<-x[1];Y[a]<-x[2];x<-x+M[,(S+3)]
SS[a]<-S+3; S<-(S+7)%%8}
 else S<-(S+1)%%8}
  list(X=(Y[-1]), Y=((dim(I)[1]-X))[-1])}