Larson Sekanina filter

[peter]

http://users.libero.it/mnico/comets/ls.htm

This is the most used filter for the morphological study of comets. It was for the first time presented by Z. Sekanina and S. M. Larson in 1984 in an article of the Astronomical Journal. In those years there were only some basic techniques to detect the directional gradient of brightness (GRADIENT FILTERS, see pag. 34); these techniques were insufficient because they analyze a single direction of the brightness variations.