1. A method of analyzing cell objects taken from a tissue section of a predetermined thickness comprising: establishing a plurality of ranges of cell object attribute values identifying cell objects to be used to generate a report; automatically measuring attributes of said cell objects, including cell object area and DNA mass for each cell object; selecting cell objects for use in generating said report by comparison of said measured attributes with said ranges of attribute values; identifying ones of said selected cell objects which are to have their DNA mass values corrected; and correcting the DNA mass value of said identified ones of said selected cell objects by an amount computed from said tissue section thickness and the measured area of the cell object to be corrected.