of grating used is sinusoidal in nature. Reflection A zone plate used as a reflector will allow radio waves to be focused as if by a parabolic reflector. This allows the reflector to be flat, and so easier to make. It also allows an appropriately patterned Fresnel reflector to be mounted flush to the side of a building, avoiding the wind loading that a paraboloid would be subject to. Software testing A bitmap representation of a zone plate image may be used for testing various image processing algorithms, such as: Image interpolation and image resampling; Image filtering. An open-source zone-plate image generator is available. See also Arago spot Diffraction grating Fresnel imager Fresnel lens Fresnel number Fresnel zone antenna Photon sieve References External links Magnetic Soft X-ray microscopy Making a photographic zone plate Whiz Kid Technomagic Zone Plate Designer Examples of zone plate photographs Optical components Photography equipment