1. A method of decomposing a target pattern having features to be imaged on a substrate so as to allow said features to be imaged in a multi-exposure process, said method comprising the steps of: (a) dividing a plurality of said features into a plurality of segments; (b) determining the image log slope (ILS) value for each of said plurality of segments; (c) determining the value of the gradient of the image log slope (ILS) value for each of said plurality of segments; and (d) assigning a phase or color to said segments based on the values of the gradient of the image log slope of each of said plurality of segments.