# US 10,502,946 B2 · Illumination systems and devices for Fourier Ptychographic imaging > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,946 B2 - Document ID: US10502946B2 - Status: Granted - Kind: B2 - Application number: 15/538,113 - Filed: 2015-12-11 - Published: 2017-12-28 - Granted: 2019-12-10 - Earliest claimed: 2014-12-23 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: James Austin Besley - Web page: https://patentgrep.com/patent/US10502946B2 ## CPC - G02B 21/367: {providing an output produced by processing a plurality of individual source images, e.g. image tiling, montage, composite images, depth sectioning, image comparison} - G02B 21/06: Means for illuminating specimens - G02B 21/361: {Optical details, e.g. image relay to the camera or image sensor (G02B21/364 takes precedence; illumination details G02B21/06 and subgroups)} - G02B 27/1066: {for enhancing image performance, like resolution, pixel numbers, dual magnifications or dynamic range, by tiling, slicing or overlapping fields of view} - G06T 3/4076: using the original low-resolution images to iteratively correct the high-resolution images - G06T 5/50: using two or more images, e.g. averaging or subtraction - G06T 2207/10056: Microscopic image - G06T 2207/10152: Varying illumination - G06T 2207/20221: Image fusion; Image merging - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A system for forming an image (110) of a substantially translucent specimen (102) has an illuminator (108) configured to variably illuminate the specimen from a plurality of angles of illumination such that (a) when each angle (495) at a given point on the specimen is mapped to a point (445) on a plane (420) perpendicular to an optical axis (490), the points on the plane have an increasing density (e.g. FIGS. 4, 11C, 11E, 12C, 12E, 13A, 14A, 14C, 14E, 15A, 15C, 15E) 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. 13A,13B) 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 (104) of the specimen based on light emitted from the illuminator according to variable illumination and filtered by an optical element (109). A processor is arranged to computationally reconstruct a relatively higher-resolution image of the specimen by iteratively updating overlapping regions (1005) of the relatively higher-resolution image in Fourier space (FIG. 10B) with the variably-illuminated, lower-resolution intensity images. ## Claims ### Claim 1 Apparatus for forming an image of a substantially translucent specimen, the apparatus comprising: a variable illuminator configured to illuminate the specimen from a plurality of angles of illumination such that 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 towards an axial position on the plane, and also such that one of the points on the plane is substantially coincident with the axial position on the plane; a detector configured to acquire a plurality of variably-illuminated, relatively lower-resolution intensity images of the specimen based on light filtered by an optical element; and a processor for computationally reconstructing a relatively higher-resolution image of the specimen by iteratively updating overlapping regions of the relatively higher-resolution image in a Fourier reconstruction space with the variably-illuminated, lower-resolution intensity images, wherein the variable illuminator is configured such that the points on the plane are spaced evenly on concentric circles and such that a number of angular locations selected around each circle increases monotonically with the radius of the circle. ### Claim 2 (depends on 1) Apparatus according to claim 1, wherein the points on the plane map to two-dimensional (2D) spatial frequencies in the Fourier reconstruction space that are approximately evenly spaced. ### Claim 3 (depends on 1) Apparatus according to claim 1, wherein the points on the plane map to 2D spatial frequencies in the Fourier reconstruction space such that a density of the spatial frequencies is greater towards a spatial frequency corresponding to a DC term of the Fourier reconstruction. ### Claim 4 (depends on 3) Apparatus according to claim 3, wherein the density of the spatial frequencies is greater towards the spatial frequency corresponding to the DC term of the Fourier reconstruction according to a power law. ### Claim 5 (depends on 1) Apparatus according to claim 1, wherein the points on the plane map to 2D spatial frequencies in the Fourier reconstruction space such that the spatial frequencies form a substantially regular pattern in a polar coordinate system in which the location of each spatial frequency in the pattern is defined by a radial coordinate that depends on a modulus of the spatial frequency, and an angular coordinate that depends on an angle of the spatial frequency. ### Claim 6 (depends on 1) Apparatus according to claim 1, wherein a density of the points on the plane drops substantially to zero outside a circular region that includes the axial position. ### Claim 7 (depends on 1) Apparatus according to claim 1, wherein the points on the plane form one or more spiral arrangements. ### Claim 8 (depends on 1) Apparatus according to claim 1, wherein the iterative updating of the overlapping regions is formed using corresponding regions in Fourier space of the variably-illuminated, relatively low-resolution images. ### Claim 9 Apparatus for forming an image of a substantially translucent specimen, the apparatus comprising: an imaging system for illuminating and imaging the specimen based on light filtered by an optical element, the imaging system including: a detector configured to acquire a plurality of relatively lower resolution intensity images of the specimen based on light filtered by the optical element, wherein the content of the of the relatively lower-resolution intensity images of the specimen corresponds to partially overlapping regions in a two-dimensional (2D) spatial frequency Fourier reconstruction space that are arranged with a substantially regular pattern in a polar coordinate system in which the location of each spatial frequency in the pattern is defined by a radial coordinate that depends on a modulus of the spatial frequency, and an angular coordinate that depends on an angle of the spatial frequency; a variable illuminator operable to control the spatial frequency associated with the relatively lower-resolution intensity images according to angles of illumination between individual light sources of the variable illuminator and the specimen such that the modulus of a spatial frequency associated with one of the partially overlapping regions is substantially zero; and a processor for computationally reconstructing a relatively higher-resolution image of the specimen by iteratively updating overlapping regions of the relatively high-resolution image in a Fourier reconstruction space with the lower-resolution intensity images, wherein positions of illumination that correspond to the light sources are arranged in a plane perpendicular to the optical axis and are spaced evenly on concentric circles such that the number of angular locations selected around each circle increases monotonically with the radius of the circle. ### Claim 10 (depends on 9) Apparatus according to claim 9, further comprising a scanning aperture. ### Claim 11 (depends on 9) Apparatus according to claim 9, further comprising a spatial light modulator. ### Claim 12 (depends on 9) Apparatus according to claim 9, further comprising a position of illumination at the centre of the circles. ### Claim 13 (depends on 9) Apparatus according to claim 9, wherein positions of illumination that correspond to the light sources form one or more spiral arrangements. ### Claim 14 (depends on 9) Apparatus according to claim 9, wherein a density of positions of illumination that correspond to the light sources drops substantially to zero outside a circular region. ### Claim 15 (depends on 9) Apparatus according to claim 9, wherein positions of illumination that correspond to the light sources and that are on a plane map to two-dimensional (2D) spatial frequencies in the Fourier reconstruction space that are approximately evenly spaced. ### Claim 16 (depends on 9) Apparatus according to claim 9, wherein positions of illumination that correspond to the light sources and that are on a plane map to 2D spatial frequencies in the Fourier reconstruction space such that the density of the spatial frequencies is greater towards a spatial frequency corresponding to a DC term of the Fourier reconstruction space. ### Claim 17 (depends on 16) Apparatus according to claim 16, wherein the density of the spatial frequencies is greater towards the spatial frequency corresponding to the DC term of the Fourier reconstruction space according to a power law. ### Claim 18 (depends on 9) Apparatus according to claim 9, wherein the iterative updating of the overlapping regions is formed using corresponding regions in the Fourier reconstruction space of the relatively low-resolution images. ### Claim 19 A non-transitory tangible computer readable storage medium having a program recorded thereon, the program being executable by a computer apparatus to form an image of a substantially translucent specimen, the program comprising: code for controlling an illuminator 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 towards an axial position on the plane, and one of the points on the plane is substantially coincident with the axial position on the plane; or (b) the illumination angles are arranged with a substantially regular pattern in a polar coordinate system 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, wherein one of the illumination angles is at or near zero; code for controlling a detector 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; and code for computationally reconstructing a relatively higher-resolution image of the specimen by iteratively updating overlapping regions of the relatively higher-resolution image in Fourier space with the variably-illuminated, lower-resolution intensity images, wherein the illuminator is controlled such that the points on the plane are spaced evenly on concentric circles and such that a number of angular locations selected around each circle increases monotonically with the radius of the circle.