langle.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 alfa=langle(x,y)
%LANGLE Determines angles of a line.
%
%        LANGLE(X,Y) return the angles of the line
%        described by X and Y.
%
%        Claudio 16 Oct. 1995.
%

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

n=length(x);
ang=[];

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

for i=2:n-1
    AB=(x(i)-x(i-1))^2  +  (y(i)-y(i-1))^2;
    BC=(x(i+1)-x(i))^2  +  (y(i+1)-y(i))^2;
    AC=(x(i+1)-x(i-1))^2 + (y(i+1)-y(i-1))^2;

    cosalfa=(AB+BC-AC)/(2*sqrt(AB*BC));
    alfa=[alfa;acos(cosalfa)*180/pi];
end

return;