Prof. Robert A. Gonsalves (Tufts University, Massachusetts, USA): Sequential Diversity Imaging

Phase diversity imaging uses two or more diverse images to estimate the aberrations introduced by the optical medium and to improve the images. The method works especially well for wide field-of-view objects like the sun, the moon, satellites, and galaxies. The diverse images can also be used to control an adaptive optic (AO), which provides sharper, diverse images to start with. We show that sequential images captured with an AO form a natural measurement set for phase diversity imaging. The sequence, itself, is a diverse set of images in which the AO changes are the phase diversities. No additional information, such as a defocused image, is required; nor is a separate wavefront sensor required. The concept could be used in most video cameras since they currently use a digital processor to control the focus (the diversity) of sequential frames. Only a beefed-up processor is needed to sharpen the images.