1. National Engineering Research Center for Information Technology in Agriculture; Room 1017, Building A, Beijing Nongke Masion, 11# Shuguang Huayuan Middle Road, Haidian District Beijing 100097 China
2. National Engineering Laboratory for Agri-product Quality Traceability; Beijing Academy of Agricultural and Forestry Sciences; Beijing 100097 China
3. Faculty of Information Technology; Beijing Univ. of Technology; Beijing 100124 China
4. Dept. de Ingeniería Agroforestal. E.T.S.I. Agronómica, Alimentaria y Biosistemas, Univ. Politécnica de Madrid; 28040 Spain