Penczek PA, Zhu J, Frank J (1996) A common-lines based method for determining orientations for N > 3 particle projections simultaneously. Ultramicroscopy 63:205–218
A method is proposed for determining the directions of projections. An arbitrary number of projections of unknown three-dimensional structure are simultaneously used as input. The method is based on common lines and uses a new discrepancy measure accounting for the uneven distribution of common lines in angular space. An application to the 70S Escherichia coli ribosome data obtained from an energy-filtering electron microscope is described.