applygmms.m

Matlab skin detector。运用高斯混合模型训练的到人的皮肤颜色分布。用于皮肤和人脸检测。

% Applies the EMed GMM matrices to an image
%
%function labelim = jrmogskin(colorim)
%  colorim must have 3 color planes
%     colorim(:,:,1) = red pixel values, 0 to 255
%     colorim(:,:,2) = green pix values, 0 to 255
%     colorim(:,:,3) = blue pix values,  0 to 255
%  skinMOG is the GMM matrix for skin models
%  nonskinMOG is the GMM matrix for background models
%  labelim is 1 for skin pixels, 0 otherwise.
%
% based on jrmogskin by:
%  Robert Collins, Penn State University, 2005
%
% modified by:
% Anthony Dotterer

function labelim = applyGMMs(colorim, skinMOG, nonskinMOG)

[nr,nc,nb] = size(colorim);
if (nb ~= 3)
    error('input image must be color\n');
end
redvals = double(reshape(colorim(:,:,1),nr*nc,1));
grevals = double(reshape(colorim(:,:,2),nr*nc,1));
bluvals = double(reshape(colorim(:,:,3),nr*nc,1));
skinscores = zeros(size(redvals));
for i=1:size(skinMOG,1)
   p = skinMOG(i,:);
   tmp = ((redvals-p(1)).^2 / p(4) + (grevals-p(2)).^2 / p(5) + (bluvals-p(3)).^2 / p(6));
   tmp = p(7) * exp(- tmp / 2) / ((2 * pi)^(3/2) * sqrt(p(4)*p(5)*p(6)));
   skinscores = skinscores + tmp;
end

nonskinscores = zeros(size(redvals));
for i=1:size(nonskinMOG,1)
   p = nonskinMOG(i,:);
   tmp = ((redvals-p(1)).^2 / p(4) + (grevals-p(2)).^2 / p(5) + (bluvals-p(3)).^2 / p(6));
   tmp = p(7) * exp(- tmp / 2) / ((2 * pi)^(3/2) * sqrt(p(4)*p(5)*p(6)));
   nonskinscores = nonskinscores + tmp;
end

labelim = reshape(skinscores > nonskinscores, nr , nc);

return;