An on-line automated analyzer of macrocontaminants is described. The analyzer is for a pulp and/or a white water stream, the analyzer comprises: a pulp classifier separating a sample from the stream into a fraction of macrocontaminants; a contaminant chamber enclosing a contaminant cell receiving the fraction; an optical chamber comprising an optical detector connected to the cell capturing at least one detected image; and a control chamber taking the at least one detected image and conducting an image analysis to determine type and quantity of at least one macrocontaminant in the fraction. The method of analysis of macrocontaminants is also described herein, the method comprises: separating a sample from the stream into a fraction of macrocontaminants; producing at least one detected image by optical measurement of the fraction; and analyzing the at least one detected image and determining the quantity and type of at least one macrocontaminant in the fraction.