twomodegauss.m

数字图象处理冈萨雷斯MATLAB源程序工具箱,包含数字图像处理各种算法

function p = twomodegauss(m1, sig1, m2, sig2, A1, A2, k)
%TWOMODEGAUSS Generates a two-mode Gaussian function.
%   P = TWOMODEGAUSS(M1, SIG1, M2, SIG2, A1, A2, K) generates a
%   two-mode, Gaussian-like function in the interval [0,1].  P is a
%   256-element vector normalized so that SUM(P) equals 1.  The mean
%   and standard deviation of the modes are (M1, SIG1) and (M2,
%   SIG2), respectively. A1 and A2 are the amplitude values of the
%   two modes.  Since the output is normalized, only the relative
%   values of A1 and A2 are important.  K is an offset value that
%   raises the "floor" of the function.  A good set of values to try
%   is M1=0.15, S1=0.05, M2=0.75, S2=0.05, A1=1, A2=0.07, and
%   K=0.002.

%   Copyright 2002-2004 R. C. Gonzalez, R. E. Woods, & S. L. Eddins
%   Digital Image Processing Using MATLAB, Prentice-Hall, 2004
%   $Revision: 1.6 $  $Date: 2003/10/13 00:54:47 $

c1 = A1 * (1 / ((2 * pi) ^ 0.5) * sig1);
k1 = 2 * (sig1 ^ 2);
c2 = A2 * (1 / ((2 * pi) ^ 0.5) * sig2);
k2 = 2 * (sig2 ^ 2);
z  = linspace(0, 1, 256);

p = k + c1 * exp(-((z - m1) .^ 2) ./ k1) + ...
    c2 * exp(-((z - m2) .^ 2) ./ k2);
p = p ./ sum(p(:));