Improved depth resolution with one-dimensional coded aperture imaging

Abstract

The method of coded aperture imaging with a one-dimensional aperture coding mask is applied to the problem of imaging a two-dimensional axial slice through a three-dimensional source distribution. A rigorous expression for the point spread function associated with the combined encoding-decoding process is derived. A least-squares procedure is then used to determine the decoding function which, for a given aperture code, minimises the mean square magnitude of the sidelobes of the point spread function. Replacement of the initial decoding function by its optimised counterpart is seen, by means of an example, to produce a point spread function which not only oscillates rapidly in sign (thus minimising the build-up of background), but also has substantially smaller mean square sidelobe magnitudes. Finally, the analysis is extended to the case of imaging with multiple views. An example demonstrates that the use of multiple views can further improve the suppression of sidelobes in the point spread function. Computer-generated plots of point spread functions accompany the analysis.