Abstract: A system for characterizing objects to be sorted in real time and making sorting decisions using lasers to excite fluorescing dyes used to tag objects such as cells which flow through the laser beam in a stream of conductive fluid. The scattered light and fluorescent light at various frequencies define a multidimensional space. These light characteristics are sensed and digitized. The data so gathered is buffered and then compared to a binary classification tree. The individual parameters cause a certain path through the binary decision tree to be taken while the cell is passing from the point in the stream where the light characteristics are gathered to a point where electrostatically charged electrodes deflect individual statically charged drops containing cells to be sorted into various sorting bins. When the decision tree has been traversed, the sorting decision for the drop containing the cell which had those parameters is done.