The method of the present invention for producing \u03b2-chitin comprises a step of cultivating an alga capable of producing \u03b2-chitin using a medium that contains nitrogen, phosphorus, silicon, and selenium, wherein the weight ratio of phosphorus to nitrogen is 0. Computation resources are then saved because no specific spatial frequency analysis is required for the selection of an appropriate gamut mapping algorithm. The anti siphon device additionally comprises an obstruction, at least a major portion of which is located between the constriction and the outlet. The system also includes a library module. The first metal level 22 having metal interconnects 15 and an inter-metal dielectric layer 19. If the closest one of the detection points is at a substantially perpendicular direction from the remote sensor, then a size of the object is determined in response to an area defined by locations of the set of detection points.