Computational Imaging of the Retina

追溯到一百多年前，在设计用于对视网膜成像的仪器中的一个长期问题是在存在来自角膜和眼透镜的强反射的情况下对从视网膜反射的微弱光进行成像。当期望在宽视场上成像时，这变得甚至更成问题。一种传统的解决方案是使用光学扫描仪在视网膜上扫描激光束。Optos超宽视场成像仪使用了这种技术，并结合了一些聪明但高成本的光学器件。各种眼科相机，包括眼底相机和间接检眼镜，通过仅在窄视场上成像来回避这个问题，并采用高度优化的光学器件来去除眩光。我们提出了一种新的计算成像方法的超宽视场视网膜相机，基于多尺度，多孔径imaging.This技术涉及分割的整体视野到平行的窄场光学通道，使视网膜图像的建设与超宽视野和只使用廉价的相机-如已开发的移动的手机。由于每个单独的摄像机物镜只需要在小视场内校正局部眼睛像差，因此每个通道都可以独立优化，以实现高质量的成像。所提出的像差的局部校正能够实现否则不可能的视场。要解决的挑战是设计和实现一个新的概念，必要的和足够的成像性能。例如，存在将通过共享孔径部分成像的场点，并且采集后图像重建需要考虑这些影响。假设优化的各个通道能够使用3.3 mm的有效孔径在整个视网膜上保持衍射限制校正，该方法有望在快照中实现5000万像素的成像。此外，所提出的创新的优点也适用于照明视网膜的挑战。因为视场被局部分割，所以如果针对每个通道实现照明系统，则照明也被局部分割，并且可以更容易地解决与在眼睛的角膜和前段处发生的反射相关联的基本问题。提出的创新代表了视网膜成像概念的一步变化：一种使用传统成像无法实现的计算成像解决方案。单个图像的准同时采集将使得可以在没有眩光的情况下拼接视网膜的超宽视图。

A perennial problem in the design of instruments for imaging the retina, dating back over one hundred years, is to image the faint light reflected from the retina in the presence of strong reflections from the cornea and ocular lens. This becomes even more of a problem when it is desired to image over a wide field of view. One traditional solution is to scan a laser beam across the retina using optical scanners. The Optos ultrawide field imager uses this technique combined with some clever, but high-cost, optics. Various ophthalmic cameras, including fundus cameras and indirect ophthalmoscopes sidestep this problem by imaging over only a narrow field of view and employ highly optimised optics to remove glare. We propose a new computational-imaging approach for an ultrawide-field retinal camera, based on multiscale, multi-aperture imaging.This technique involves segmenting the overall field of view into parallel narrow-field optical channels, to enable construction of retinal images with ultra-wide fields of view and using only inexpensive cameras - such as have been developed for mobile phones. Because each individual camera objective is required only to correct for the local eye aberrations over a small field of view, each channel can be optimised independently to achieve high-quality imaging. The local correction of aberrations that is proposed enables an otherwise impossible field of view. The challenge to solve is to design and implement a new concept with the necessary and sufficient imaging performance. For example, there are field points that will be imaged partially through shared apertures, and the post-acquisition image reconstruction needs to account for these effects. Assuming the optimised individual channels are able to maintain a diffraction-limited correction over the entire retina using an effective aperture of 3.3mm, the approach promises to enable 50-megapixel imaging in a snapshot. Additionally, the advantages of the proposed innovation also apply to the challenge of illuminating the retina. Because the field of view is segmented locally, so is the illumination if an illumination system is implemented for each channel, and the fundamental issues associated with reflections occurring at the cornea and anterior segment of the eye can be more easily solved. The proposed innovation represents a step-change in the concept of retinal imaging: a computational imaging solution that cannot be achieved using conventional imaging. The quasi-simultaneous acquisition of the individual images will make it possible to mosaic an ultra-wide view of the retina without glare.