Аннотация:In this short article we show how the kernel-based density estimation method are usually applied to search for clusters/dwarf galaxies in large surveys. These method proved to be very effective in last few years. Some simple modifications of these methods are discussed, which allow to perform deeper searches for the substructure in the surveys. Also I show how the generalized Hough transform can be applied to the large stellar catalogs to find stellar streams in the MW halo. The Hough transform of the SDSS data allows to detect all know large stellar streams in SDSS.