A method of determining a state of biofouling of a membrane is provided. The visual display includes an opaque base object having a front surface and a plurality of microperforations therethrough from the front surface to a back surface. The method further comprises extracting the at least two image objects from the obtained image data, determining, from the obtained image data, the angle between the lines formed between each of the objects and the reference point, and using the at least two image objects andor the image data for positioning the first wireless device based on the determined angle. Methods of used and kits comprising the composition are also disclosed.