Restoration of images for the Hubble Space Telescope

The Hubble Space Telescope image quality is degraded significantly as a result of the spherical aberration in the primary mirror. Although the forthcoming HST servicing mission will deploy corrective optics systems and a second-generation camera with built-in correctors, the current and archival images for the past three years require the use of restoration techniques in order to achieve the full scientific potential of the HST mission. In addition, we expect that the restoration techniques now being developed will continue to be utilized on post- servicing mission imagery in order to remove the remaining diffraction features and optimize dynamic range. A variety of well-known image restoration techniques, such as Wiener filters, Richardson-Lucy, Jansson-van Cittert, CLEAN, and maximum entropy, have been applied to HST imaging with reasonable success. However, all techniques have been hampered by incomplete knowledge of the point spread function and the space variance of the PSF in the Wide Field/Planetary Camera, HST's most frequently used imager. The best restoration results to date have been obtained by utilizing observed PSFs (an optimal exposure which minimizes noise and image defects) on small enough subsets of the total field of view so that the PSF variation can be ignored.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.