This is an easy to use active contours api for Fiji(ImageJ). This based on: [https://imagej.net/Level_Sets ](Level Sets Plugin). All the parameters are self-explanatory and their detials can be found [ https://imagej.net/Level_Sets ] here.
Include the ActiveContours.java in the same directory of your PlugIn file or simply copy paste the function in your class(Do make necessary changes).