自适应光学眼底相机,由于较高的成像分辨率和人眼等晕角的存在,单次成像的视场被限制在1°左右。必须实现单个视场的精确定位和多个视场的图像拼接,才能得到完整的眼底图像。为了精确定位,文中分析视标引导成像视场的原理,设计了新型的视标引导系统。平行光照明视标,并通过透镜聚焦于人眼瞳孔中心,这样能够精确测量眼底成像视场的位置。基于此搭建的自适应光学系统可在22.6°的眼底范围内成像,精度达到0.003°。这套系统成功实现了单个细胞的追踪和眼底血管的大视场拼接,这将有益于液晶自适应光学系统在临床眼科的应用和推广。
For the high imaging resolution of the adaptive optics(AO) fundus camera and the existence of the eye isoplanatic angle, a single adaptive optics imaging field of view was limited to 1 °. To get a complete fundus image, accurate fixation of one single field of view and image mosaicking of multiple fields of view must be achieved. In order to accurately track fundus imaging area, the principle to guide imaging field of view with a visual target was analyzed and a novel visual target system was designed.Parallel light was used to illuminate the target and focused to the center of the human pupil through a lens before the eye. In this way, the retinal position of the imaging field of view could be precisely measured. The visual target guidance system was introduced into a liquid crystal adaptive optics camera.The imaging field ranged to 22.6° on the retina. The fixation accuracy was achieved to 0.003 °. This set of adaptive optics system successfully tracked single retinal photoreceptor cell and got stitched images of fundus blood vessels, which was beneficial for application and popularization of liquid crystal AO system in clinical ophthalmology.