SOURCEPATH = 'E:\ChenXiaochuan\Work\pics\';
ORIGINPATH = 'E:\ChenXiaochuan\Work\graypics\';

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%  using any parameters below to specify the unified new image size
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
IMWIDTH = 512;
IMHIEIGHT = 512;
IMRATIO = 0.5;

filelist = dir(SOURCEPATH);
filenum = size(filelist,1)-2;
filename= [];

for i = 1:1:filenum
    temp = filelist(i+2).name;
    filename = [filename;temp];
end

for i = 1:1:filenum
    I = imread(strcat(SOURCEPATH,filename(i,:)));
    I = double(I);
    Ig = 0.3*I(:,:,1) + 0.59*I(:,:,2) + 0.11*I(:,:,3);
    Ig = imresize(Ig, IMRATIO, 'bilinear');
    Ig = uint8(Ig);
    tempname = filename(i,:);
    tempname(end-2:end) = 'bmp';
    imwrite(Ig,strcat(ORIGINPATH,'gray',tempname));
end