A method to determine the size of the structuring element in morphological correction of non-uniform illumination

Correction of uneven illumination in images is frequently used as a preprocessing step, for which morphological processing is a well established technique. This task has some specific characteristics for images containing disjoint blobs. These images appear frequently in applications like cellular imaging, where it is often necessary to process them in large amounts. In such cases, achieving a high degree of automation becomes an important factor. When correcting uneven illumination by morphological processing for this class of images, selecting an appropriate size for the structuring element (SE) is a relevant issue. In this work, a method based in grayscale morphological operations is presented, to determine an appropriate size of the SE. The effectiveness of the method was tested through simulations using images derived from real world examples. Results are presented in terms of tables showing the precision in recovering the original image intensities, as well as through illustrative images.