1. A method of designing metrology targets comprising: identifying, with one or more processors, one or more continuous regions in a target design; introducing, with the one or more processors, one or more selected filling elements into the one or more identified continuous regions to form a modified target design, wherein one or more parameters of the one or more introduced filling elements are determined based on a contrast requirement and an inaccuracy requirement of the modified target design, wherein contrast and inaccuracy are dependent on an amount of empty region within the one or more continuous regions; and producing a target with the modified target design on a wafer.