Abstract. This paper addresses the problem of intensity correction of fluorescent confocal laser scanning microscope (CLSM) images. CLSM images are frequently used in medical domain for obtaining 3D information about specimen structures by imaging a set of 2D cross sections and performing 3D volume reconstruction afterwards. However, the images of optical sections acquired from fluorescent CLSM demonstrate significant lateral intensity heterogeneity, which is well understood as one of the major barriers to accurate image analysis, e.g., quantitative analysis, segmentation, or visualization. The main contribution of the proposed work is in development of an intensity heterogeneity correction technique that (a) adjusts intensity heterogeneity in lateral plane of the sub-volume, (b) preserves fine structural details, and (c) enhances image contrast, by performing spatially adaptive mean-weight filtering. Furthermore, we provide data-driven parameter optimization method and evaluation metr...