llength.m

matlab处理图像的一些基本方法。其中有一部分mex程序需要安装编译

function len=llength(x,y)
%LLENGTH Length of a line.
%
%        LLENGTH(X,Y) return the length of the line 
%        described by X and Y.
%        The length is calculated as the sum of the
%        distances between two consecutive points.
%        
%        Claudio 6 September 1994.
%

%
% Copyright (c) 1995 by Claudio Rivetti and Mark Young
% [e-mail],    [e-mail]
%

n=length(x);

if n ~= length(y)
  error('Vectors must be the same lengths.')
end

xi  = x(1:n-1);
xii = x(2:n);
yi  = y(1:n-1);
yii = y(2:n); 
len = sum(sqrt((xi-xii).^2 + (yi-yii).^2)); 

return;