Hi Yan Zhang, When I read your 'test_ChanVese_model_3d.m' and 'test_hybrid_model_3d.m', I have a problem that cannot read head_ct.mat file. It's showing error "??? Error using ==> load Unable to read MAT file head_ct.mat. File may be corrupt." is it because of version different? I am using Matlab 6.5 please advise. thanks