@article {jbatenbuwvaarlejsijbers2011, title = {A Semi-Automatic Algorithm for Grey Level Estimation in Tomography}, journal = {Pattern Recognition Letters}, volume = {32}, number = {9}, year = {2011}, month = {July}, pages = {1395-1405}, author = {Kees Joost Batenburg and Wim Van Aarle and Jan Sijbers} }