Image based adaptive optics through optimisation of low spatial frequencies

Delphine Debarre (1) , Martin J. Booth (2) , Tony Wilson (2)

1 LIPhy - Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères]
2 Department of Engineering Science

We present a wave front sensorless adaptive optics scheme for an incoherent imaging system. Aberration correction is performed through the optimisation of an image quality metric based upon the low spatial frequency content of the image. A sequence of images is acquired, each with a different aberration bias applied and the correction aberration is estimated from the information in this image sequence. It is shown, by representing aberrations as an expansion in Lukosz modes, that the effects of different modes can be separated. The optimisation of each mode becomes independent and can be performed as the maximization of a quadratic function, requiring only three image measurements per mode. This efficient correction scheme is demonstrated experimentally in an incoherent transmission microscope. We show that the sensitivity to different aberration magnitudes can be tuned by changing the range of spatial frequencies used in the metric.We also explain how the optimization scheme is related to other methods that use image sharpness metrics.

Mots clés: Active or adaptive optics; Wave-front sensing; Optical transfer functions

Domaines: Optique [physics.optics]

Delphine Debarre, Martin J. Booth, Tony Wilson. Image based adaptive optics through optimisation of low spatial frequencies. Optics Express, 2007, 15, pp.8176-8190. ⟨10.1364/OE.15.008176⟩. ⟨hal-00681926⟩