Feature extraction by shape matching - Feature Extraction and Image Processing - page 210

else
for j=3:rows
c=y+j;
i=round(x+(c-y)/m);
if(c>0 & c<rows & i>0 & i<columns & M(c,i)~=0)
x1=i ; y1=c;
i=rows;
end
c=y-j;
i=round(x+(c-y)/m);
if(c>0 & c<rows & i>0 & i<columns & M(c,i)~=0)
x1=i; y1=c;
i=rows;
end
end
end

if(x1~=-1)
%compute beta
phi=tan(Ang(y,x));
phj=tan(Ang(y1,x1));
if((1+phi*phj)~=0)
beta=atan((phi-phj)/(1+phi*phj));
else
beta=1.57;
end

%compute k
if((x-xr)~=0)
ph=atan((y-yr)/(x-xr));
else
ph=1.57:
end
k=ph-Ang(y,x);

%insert in the table
i=round((beta+(pi/2))/D;
if (i==0)i=1; end;

V=F(i)+1;

if(V>s)
s=s+1;
T(:,s)=zeros(entries, 1);
end;

T(i,V)=k;
F(i)=F(i)+1;
end

end %if
end %y
end %x

Code 5.12 Constructing of the invariant R-table