Title :
Adaptive optics for ophthalmic imaging
Author :
Diaz-Santana, L. ; Gasson, Pad ; Munro, Ian ; Dainty, Chris
Author_Institution :
Appl. Vision Res. Centre, City Univ., London, UK
Abstract :
In this report we present an adaptive optics system with a closed-loop bandwidth between 12 Hz and 25 Hz. This system scans the wavefront sensing beam at 1 kHz over a maximum angle of 1 degree and de-scans it on the exit path to eliminate speckle, as previously done by Hofer et.al to study the dynamics of ocular aberrations without correction. This has improved the signal to noise ratio in the wavefront sensor signal, hence ensuring a reduction of ocular aberrations in all of the subjects tested. The system uses a Shack-Hartmann wavefront sensor and a DALSA CCD camera. MTF was reconstructed from the images using a Wiener de-convolution algorithm assuming a quasidiffraction limited first pass, followed by a discrete Fourier transform.
Keywords :
CCD image sensors; aberrations; adaptive optics; closed loop systems; deconvolution; discrete Fourier transforms; eye; image reconstruction; optical transfer function; wavefront sensors; 1 kHz; 12 to 25 Hz; DALSA CCD camera; MTF; Shack-Hartmann wavefront sensor; Wiener de-convolution algorithm; adaptive optics; closed-loop system; discrete Fourier transform; image reconstruction; ocular aberrations; ophthalmic imaging; quasidiffraction; signal to noise ratio; Adaptive optics; Bandwidth; Charge coupled devices; Charge-coupled image sensors; Image reconstruction; Optical imaging; Sensor systems; Signal to noise ratio; Speckle; Testing;
Conference_Titel :
Lasers and Electro-Optics Europe, 2003. CLEO/Europe. 2003 Conference on
Print_ISBN :
0-7803-7734-6
DOI :
10.1109/CLEOE.2003.1313793
