# US 2018/0027173 A1 · Fast Auto-Focus in Imaging > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0027173 A1 - Document ID: US20180027173A1 - Status: Published application - Kind: A1 - Application number: 15/723,788 - Filed: 2017-10-03 - Published: 2018-01-25 - Earliest claimed: 2011-02-01 - Assignees: Roche Diagnostics Hematology, Inc. - Applicants: Roche Diagnostics Hematology, Inc. - Inventors: Michael Zahniser - Web page: https://patentgrep.com/patent/US20180027173A1 ## CPC - G02B 21/244: {using image analysis techniques} - G06T 2207/10148: Varying focus - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract The disclosure relates to methods and systems for automatically focusing multiple images of one or more objects on a substrate. The methods include obtaining, by a processor, a representative focal distance for a first location on the substrate based on a set of focal distances at known locations on the substrate. The methods also include acquiring, by an image acquisition device, a set of at least two images of the first location. The images are each acquired using a different focal distance at an offset from the representative focal distance. The methods further include estimating, by a processor, an ideal focal distance corresponding to the first location based on comparing a quality of focus for each of the images, and storing the estimated ideal focal distance and the first location in the set of focal distances at known locations. ## Claims ### Claim 1 (canceled) ### Claim 2 A method for automatically focusing multiple images of one or more objects on a substrate, the method comprising: a) obtaining, by one or more processing devices, a representative focal distance for a first location on the substrate based on a set of focal distances at known locations on the substrate; b) acquiring, by an image acquisition device, a set of at least two images of the first location based on the representative focal distance, wherein the set of images is acquired under illumination by at least two different colors and each of one or more images under a particular color is acquired using a focal distance at a corresponding offset from the representative focal distance; c) estimating, by the one or more processing devices, an ideal focal distance based on the acquired set of images; and d) storing the estimated ideal focal distance and the first location in the set of focal distances at known locations. ### Claim 3 (depends on 2) The method of claim 2, wherein at least two images are acquired under illumination by each color. ### Claim 4 (depends on 2) The method of claim 2, wherein estimating the ideal focal distance corresponding to the first location further comprises: calculating a focal distance offset for each of the different colors; determining an average focal distance offset based on the focal distance offsets calculated for the different colors; and estimating the ideal focal distance corresponding to the first location based on the average focal distance offset. ### Claim 5 (depends on 2) The method of claim 2, wherein the representative focal distance is estimated as a weighted average of at least two focal distances from the set of focal distances at known locations, wherein a weight for a given focal distance is calculated based on a distance of the corresponding location from the first location. ### Claim 6 (depends on 4) The method of claim 4, wherein calculating the focal distance offset for a given color comprises comparing a quality of focus for each of the images of the given color. ### Claim 7 (depends on 6) The method of claim 6 wherein comparing the quality of focus further comprises calculating, for each image, a focus score by quantifying differences between neighboring pixels. ### Claim 8 (depends on 7) The method of claim 7, wherein the focus score comprises a Brenner score. ### Claim 9 (depends on 7) The method of claim 7, wherein calculating the focal distance offset for the given color comprises fitting a curve to logarithms of focus scores as a function of focal distance. ### Claim 10 (depends on 9) The method of claim 9, wherein an equation for the curve is selected based on the number of images acquired for each color. ### Claim 11 (depends on 2) The method of claim 2, wherein the at least two different colors are selected from a group consisting of red, yellow, green, and blue. ### Claim 12 A system comprising: an image acquisition device configured to acquire a set of at least two images of the first location based on a representative focal distance, wherein the set of images is acquired under illumination by at least two different colors and each of one or more images under each a particular color is acquired using a focal distance at a corresponding offset from the representative focal distance; and one or more processing devices, connected to the image acquisition device, the one or more processing devices configured to: obtain the representative focal distance for a first location on the substrate based on a set of focal distances at known locations on the substrate, estimate an ideal focal distance based on the acquired set of images, and store the estimated ideal focal distance and the first location in the set of focal distances at known locations. ### Claim 13 (depends on 12) The system of claim 12, wherein at least two images are acquired under illumination by each color. ### Claim 14 (depends on 12) The system of claim 12, wherein estimating the ideal focal distance corresponding to the first location further comprises: calculating a focal distance offset for each of the different colors; determining an average focal distance offset based on the focal distance offsets calculated for the different colors; and estimating the ideal focal distance corresponding to the first location based on the average focal distance offset. ### Claim 15 (depends on 12) The system of claim 12, wherein the representative focal distance is estimated as a weighted average of at least two focal distances from the set of focal distances at known locations, wherein a weight for a given focal distance is calculated based on a distance of the corresponding location from the first location. ### Claim 16 (depends on 14) The system of claim 14, wherein calculating the focal distance offset for a given color comprises comparing a quality of focus for each of the images of the given color. ### Claim 17 (depends on 16) The system of claim 16, wherein comparing the quality of focus further comprises calculating, for each image, a focus score by quantifying differences between neighboring pixels. ### Claim 18 (depends on 17) The system of claim 17, wherein the focus score comprises a Brenner score. ### Claim 19 (depends on 17) The system of claim 17, wherein calculating the focal distance offset for the given color comprises fitting a curve to logarithms of focus scores as a function of focal distance. ### Claim 20 (depends on 19) The system of claim 19, wherein an equation for the curve is selected based on the number of images acquired for each color. ### Claim 21 (depends on 12) The system of claim 12, wherein the at least two different colors are selected from a group consisting of red, yellow, green, and blue. ### Claim 22 A non-transitory computer readable storage device, having encoded thereon computer readable instructions that causes one or more processing devices to execute operations comprising: obtaining a representative focal distance for a first location on the substrate based on a set of focal distances at known locations on the substrate; obtaining a set of at least two images of the first location based on the representative focal distance, wherein the set of images is acquired under illumination by at least two different colors and each of one or more images under a particular color is acquired using a focal distance at a corresponding offset from the representative focal distance; estimating an ideal focal distance based on the acquired set of images; and storing the estimated ideal focal distance and the first location in the set of focal distances at known locations. ### Claim 23 (depends on 22) The computer readable storage device of claim 22, wherein at least two images are acquired under illumination by each color. ### Claim 24 (depends on 22) The computer readable storage device of claim 22, wherein estimating the ideal focal distance corresponding to the first location further comprises: calculating a focal distance offset for each of the different colors; determining an average focal distance offset based on the focal distance offsets calculated for the different colors; and estimating the ideal focal distance corresponding to the first location based on the average focal distance offset. ### Claim 25 (depends on 22) The computer readable storage device of claim 22, wherein the representative focal distance is estimated as a weighted average of at least two focal distances from the set of focal distances at known locations, wherein a weight for a given focal distance is calculated based on a distance of the corresponding location from the first location. ### Claim 26 (depends on 24) The computer readable storage device of claim 24, wherein calculating the focal distance offset for a given color comprises comparing a quality of focus for each of the images of the given color. ### Claim 27 (depends on 26) The computer readable storage device of claim 26, wherein comparing the quality of focus further comprises calculating, for each image, a focus score by quantifying differences between neighboring pixels. ### Claim 28 (depends on 27) The computer readable storage device of claim 27, wherein the focus score comprises a Brenner score. ### Claim 29 (depends on 27) The computer readable storage device of claim 27, wherein calculating the focal distance offset for the given color comprises fitting a curve to logarithms of focus scores as a function of focal distance. ### Claim 30 (depends on 29) The computer readable storage device of claim 29, wherein an equation for the curve is selected based on the number of images acquired for each color. ### Claim 31 (depends on 22) The computer readable storage device of claim 22, wherein the at least two different colors are selected from a group consisting of red, yellow, green, and blue.