Dear support staff, At the moment I am writing a paper about an approach to incorporate combinations of texture filters into the classification process. Therefore I use most of the available occurence and co-occurence texture filters available in ENVI (4.4). However, I cannot find the mathematical formula's on which these texture filters are based in the ENVI help. In various literature are examples of formula's, but I am not sure ENVI uses these exact formula's. It is especially hard to find the formula's for the occurence filters. Thanks in advance for the information. Regards, Johan Beekhuizen