Illumination systems and devices for fourier ptychographic imaging

Abstract

A system for forming an image () of a substantially translucent specimen () has an illuminator () configured to variably illuminate the specimen from a plurality of angles of illumination such that (a) when each angle () at a given point on the specimen is mapped to a point () on a plane () perpendicular to an optical axis (), the points on the plane have an increasing density (e.g. FIGS.C,E,C,E,A,A,C,E,A,C,E) towards an axial position on the plane; or (b) the illumination angles are arranged with a substantially regular pattern in a polar coordinate system (FIG.A,B) defined by a radial coordinate that depends on the magnitude of the distance from an optical axis and an angular coordinate corresponding to the orientation of the angle relative to the optical axis. A detector is configured to acquire a plurality of variably illuminated, relatively lower-resolution intensity images () of the specimen based on light emitted from the illuminator according to variable illumination and filtered by an optical element (). A processor is arranged to computationally reconstruct a relatively higher-resolution image of the specimen by iteratively updating overlapping regions () of the relatively higher-resolution image in Fourier space (FIG.B) with the variably-illuminated, lower-resolution intensity images.