EN
The possibilities given by the digital analysis of microscopic images in the area of the investigation of morphology and physiology of filamentous fungi are presented in this article. At the beginning, theoretical background of the digital image analysis from the form of the image, through the mathematical functions used for their processing, to the determination of the objects? dimensions are described. In the second part of the article, practical application of the discussed techniques was presented on the basis of the investigation of physiological and morphological properties of Aspergillus niger in the process of citric acid biosynthesis.