An algorithm for determination of threshold value in extruded products by the method of maximum increments: modi cation of Otsu method. There are presented the results of comparative analysis of threshold value determination in the extruded products with the use of developed new algorithm. The original and modi ed Otsu algorithms were compared. In calculations of porosity indices of the extrudate cross section, the threshold values determined automatically with the use of investigated algorithms were compared with indications of an experts’ panel. The results of threshold value calculated with the use of the proposed algorithm were closer to values indicated by the expert panel, than that obtained with the use of comparative algorithms. However, the proposed method tends to overstate the threshold value; in some cases it can cause losing the pores of small lacunarity on the bit map calculated by this method.