Wavefront sensor optimisation with ridgelets for astronomical image restoration

Specific wavefront aberrations cannot be directly measured from an image. A wavefront sensor can use intensity variations from a point source to estimate wavefront aberration. However, processing can be computationally intensive and this is a challenge for real-time image restoration. A relatively simple wavefront sensor (WFS) can be implemented using two focal plane images. Typically, measured aberration data from these sensors are used in closed-loop control, where a conjugate of the aberration using a deformable mirror (DM) is applied to the optical path for compensation. However, closed-loop adaptive optics systems are hardware intensive. On the other hand, open-loop control simplifies the overall system, but computational demands are considerably higher. In this paper, we discuss how the ridgelet method, which has a broad application in signal analysis, is used with the geometric wavefront sensor to enhance performance in an open-loop configuration.