# US 11,910,104 B2 · All-in-focus imager and associated method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,910,104 B2 - Document ID: US11910104B2 - Status: Granted - Kind: B2 - Application number: 17/594,458 - Filed: 2020-04-19 - Published: 2022-06-30 - Granted: 2024-02-20 - Earliest claimed: 2019-04-19 - Assignees: Arizona Board of Regents on Behalf of the University of Arizona, a body corporate - Applicants: Arizona Board of Regents On Behalf of the University of Arizona - Inventors: John Koshel; Emma Landsiedel - Web page: https://patentgrep.com/patent/US11910104B2 ## CPC - G01B 11/2441: {using interferometry} - G02B 27/0075: {with means for altering, e.g. increasing, the depth of field or depth of focus} - G01B 9/0203: {With imaging systems} - G01B 9/0209: Low-coherence interferometers - G01B 11/0608: {Height gauges} - G03B 13/34: Power focusing - H04N 23/671: {in combination with active ranging signals, e.g. using light or sound signals emitted toward objects} - H04N 23/676: {Bracketing for image capture at varying focusing conditions} - H04N 23/951: by using two or more images to influence resolution, frame rate or aspect ratio - H04N 23/958: for extended depth of field imaging - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method for imaging of an object includes, for each of a plurality of surface-regions of the object, determining a corresponding image-sensor pixel group of a camera illuminated by light propagating from the surface-region via a lens of the camera. The method also includes, after the step of determining and for each surface-region: (i) changing a distance between the object and the lens such that the surface region intersects an in-focus object-plane of the camera and the lens forms an in-focus surface-region image on the corresponding image-sensor pixel group; (ii) capturing, with the corresponding image-sensor pixel group, the in-focus surface-region image of the surface-region; and (iii) combining the in-focus surface-region images, obtained by performing said capturing for each surface-region, to yield an all-in-focus image of the object. ## Claims ### Claim 1 A method for all-in-focus imaging of an object, comprising: for each of a plurality of surface-regions of the object, determining a corresponding image-sensor pixel group of a camera illuminated by light propagating from the surface-region of the object via a lens of the camera; after the step of determining and for each surface-region: changing a distance between the object and the lens such that the surface region intersects an in-focus object-plane of the camera and the lens forms an in-focus surface-region image on the corresponding image-sensor pixel group, capturing, with the corresponding image-sensor pixel group, the in-focus surface-region image of the surface-region; and combining a plurality of in-focus surface-region images, obtained by performing said capturing for each of the plurality of surface-regions, to yield an all-in-focus image of the object. ### Claim 2 (depends on 1) The method of claim 1, at least one of the image-sensor pixel groups being discontiguous. ### Claim 3 (depends on 1) The method of claim 1, changing the distance comprising moving the object. ### Claim 4 (depends on 1) The method of claim 1, a light-sensing plane of the camera being located at an image-distance from the lens, and in the step of capturing, a focal length of the lens, a distance between the in-focus object-plane and the lens, and the image-distance collectively satisfying the Gaussian lens formula. ### Claim 5 (depends on 1) The method of claim 1, further comprising utilizing optical interferometry to perform the step of determining the image-sensor pixel group. ### Claim 6 (depends on 4) The method of claim 4, each pixel group including a respective plurality of image-sensor pixels, and determining the image-sensor pixel group comprising: positioning the object at a plurality of positions along an axis parallel to a test optical-beam propagating along a test-arm of an interferometer and illuminating the object such that the object reflects the test optical-beam as a reflected optical-beam; and for each of the plurality of positions: determining a group of reference-sensor pixels, of a reference sensor, located at an output port of the interferometer, that detect interference between a reference beam and a first part of the reflected optical-beam reflected by one surface-region of the plurality of surface regions; and determining the image-sensor pixel group as a plurality of pixels of the image sensor illuminated by a second part of the reflected optical beam reflected by the one surface-region. ### Claim 7 (depends on 6) The method of claim 6, further comprising: illuminating the object with the test optical-beam, the plurality of surface-regions reflecting the test optical-beam as the reflected optical-beam having a plurality of reflected-beam regions each corresponding to a one of the plurality of surface-regions; illuminating a reference sensor, located at an output port of the interferometer, with the reference beam propagating from a reference mirror of the interferometer, the reference sensor including a plurality of reference-sensor pixels; splitting the reflected optical-beam into the first part of the reflected optical-beam and a second part of the reflected optical-beam; illuminating the reference sensor with the first part of the reflected optical-beam, each of the plurality of reference-sensor pixels being illuminated by a respective one of the plurality of reflected-beam regions; and illuminating the image sensor with the second part of the reflected optical-beam, each of the plurality of image-sensor pixels being illuminated by a respective one of the plurality of reflected-beam regions, and therefore being mapped to the one of the plurality of reference-sensor pixels illuminated by the respective one of the plurality of reflected-beam regions. ### Claim 8 (depends on 6) The method of claim 6, further comprising, for each of the plurality of positions: repositioning the object at each the plurality of positions; and, at each of the plurality of positions, capturing an image of the surface-region of the plurality of surface-regions with the determined image-sensor pixel group. ### Claim 9 (depends on 6) The method of claim 6, the step of determining a group of reference-sensor pixels comprising generating, with the reference sensor, a signal in response to a change in amplitude of a recombined beam thereon composed of the reference beam and the first part of the reflected optical-beam. ### Claim 10 (depends on 6) The method of claim 6, all locations within each surface region being closest to a same respective object plane of a plurality of object planes each displaced from and parallel to an in-focus object-plane of the camera, a separation between adjacent object planes of the plurality of object planes being greater than or equal to a coherence length of the test optical-beam. ### Claim 11 (depends on 1) The method of claim 1, all locations within each surface region being closest to a same respective object plane of a plurality of object planes each displaced from and parallel to an in-focus object-plane of the camera. ### Claim 12 (depends on 11) The method of claim 11, a separation between adjacent object planes of the plurality of object planes being greater than or equal to a depth of field of the camera. ### Claim 13 An all-in-focus imager comprising: a camera including an image sensor; an interferometer including: a reference sensor having a plurality of reference-sensor pixels, a reference mirror terminating a reference arm of the interferometer, and a first beamsplitter configured to split, at a first beam-splitting interface, an input light beam into (i) a test optical-beam propagating from the first beam-splitting interface to an object, such that the object terminates a test arm of the interferometer and reflects the test optical-beam as a reflected optical-beam, and (ii) a reference beam propagating from the first beam-splitting interface to the reference mirror and from the reference mirror to the reference sensor; a second beamsplitter configured to direct (i) a first part of the reflected optical-beam to the reference sensor and (ii) a second part of the reflected optical-beam to the camera; and an actuator configured to change a length of the test arm by moving the object. ### Claim 14 (depends on 12) The all-in-focus imager of claim 12, an optical path length between a second beam-splitting interface of the second beamsplitter and the first beam-splitting interface being equal to an optical path length between the second beam-splitting interface and a lens of the camera. ### Claim 15 (depends on 12) The all-in-focus imager of claim 12, the second beamsplitter being between the first beamsplitter and a termination of the test arm, and being configured to transmit the first part of the reflected optical-beam and reflect the second part of the reflected optical-beam. ### Claim 16 (depends on 12) The all-in-focus imager of claim 12, the second beamsplitter being between the camera and the first beamsplitter, and being configured to reflect the first part of the reflected optical-beam and transmit the second part of the reflected optical-beam. ### Claim 17 (depends on 12) The all-in-focus imager of claim 12, further comprising a light source configured to generate the input light beam. ### Claim 18 (depends on 12) The all-in-focus imager of claim 12, the reference sensor being an event-based vision sensor. ### Claim 19 (depends on 12) The all-in-focus imager of claim 12, further comprising a processor communicatively coupled to the camera, the reference sensor, and the actuator; and memory storing non-transitory computer-readable instructions that, when executed by the processor, control the processor to: control the actuator to vary the length of the test arm. ### Claim 20 (depends on 12) The all-in-focus imager of claim 12, further comprising: a processor communicatively coupled to the camera, the reference sensor, and the actuator; and memory storing non-transitory computer-readable instructions that, when executed by the processor, control the processor to: for each of a plurality of surface-regions of the object, determine a corresponding image-sensor pixel group of the camera illuminated by light propagating from the surface-region of the object via a lens of the camera, all locations within each surface region being closest to a respective object plane of a plurality of object planes each displaced from and parallel to an in-focus object-plane of the camera; after the step of determining and for each surface-region: change a distance between the object and the lens such that the surface region intersects the in-focus object-plane and the lens forms an in-focus surface-region image on the corresponding image-sensor pixel group, capture, with the corresponding image-sensor pixel group, the in-focus surface-region image of the surface-region; and; and combine a plurality of in-focus surface-region images, obtained by performing said capturing for each of the plurality of surface-regions, to yield an all-in-focus image of the object.