Information about arbitrarily shaped wavefronts can be recorded as computer-generated holograms. There are convenient techniques for producing image plane holograms consisting of many narrow fringes similar to interferograms. These diffractive filters are suitable for realization of generalized elements for use in optical systems. These holograms can be applied to accomplish phase transformations, geometrical transformations, and combinations of phase and geometrical transformations. Computer-generation of holograms allows introduction of general carrier configurations. Examples of circular carrier recordings are shown.