# US 7,609,869 B2 · Processing method for a two-dimensional initial image and objects corresponding thereto > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,869 B2 - Document ID: US7609869B2 - Status: Granted - Kind: B2 - Application number: 11/472,844 - Filed: 2006-06-22 - Published: 2006-12-28 - Granted: 2009-10-27 - Earliest claimed: 2005-06-22 - Assignees: Siemens Aktiengesellschaft - Inventors: Philipp Bernhardt; Markus Lendl - Web page: https://patentgrep.com/patent/US7609869B2 ## CPC - G06T 5/10: using non-spatial domain filtering - G06T 5/73: Deblurring; Sharpening - G06T 2207/10116: X-ray image - G06T 2207/20016: Hierarchical, coarse-to-fine, multiscale or multiresolution image processing; Pyramid transform - G06T 2207/20021: Dividing image into blocks, subimages or windows - G06T 2207/30004: Biomedical image processing - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A computer dismantles a two-dimensional initial image into partial images containing components that vary locally with partial image frequencies and a residual image containing a direct component which is locally invariable. For each partial image and residual image the computer determines a weighting factor and sums the weighted images into a final image. Based on a comparison of the partial image frequencies with a target frequency, the computer determines a partial image as a pilot image and its frequency as a pilot frequency. The computer determines weighting factors of the partial images so that partial images whose frequencies are below the pilot frequency are weighted less than the pilot image, and partial images whose frequencies are above the pilot frequency makes a large contribution when the noise component in the initial image is small and a small contribution when the noise component in the initial image is large. ## Claims ### Claim 1 A method for processing a two-dimensional initial image used in a medical procedure, comprising: dismantling the two-dimensional initial image into a plurality of partial images and a residual image by a computer, wherein each of the partial images contains a component of the two-dimensional initial image that varies locally with a predetermined partial image frequency departing from zero, wherein the residual image contains a direct component of the two-dimensional initial image that is locally invariable; assigning one of the partial images as a pilot image and assigning a frequency of the pilot image as a pilot frequency based on a comparison of frequencies of the partial images with a target frequency; determining a plurality of weighting factors for the partial images and the residual image; and summing the weighted partial images and the weighted residual image into a final image, wherein the weighting factors of the partial images are determined by the computer so that: the partial images with lower frequencies than the pilot frequency are weighted less than the pilot image but still contribute to the final image, the partial images with higher frequencies above the pilot make: a large contribution to the final image when a noise component in the initial image is small, or a small contribution to the final image when the noise component in the initial image is large. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein a weighting factor of a selected low-frequency partial image is determined so that: the selected low-frequency partial image is weighted decreasingly as a frequency of the selected low-frequency partial image departs further away from the pilot frequency, and a quotient of amplitudes of two weighted low-frequency partial images whose partial image frequencies are directly adjacent is limited to a first ratio. ### Claim 3 (depends on 2) The method as claimed in claim 2, wherein an individual weighting factor of the selected low-frequency partial image is determined so that a quotient of an amplitude of the selected low-frequency partial image weighted with the individual weighting factor and an amplitude of a non-weighted low-frequency partial image having a next higher partial image frequency is limited to the first ratio, and wherein the weighting factor of the selected low-frequency partial image is determined by multiplying the individual weighting factor of the selected low-frequency partial image with a weighting factor of the pilot image and with individual weighting factors of remaining low-frequency partial images whose partial image frequencies are higher than a frequency of the selected low-frequency partial image. ### Claim 4 (depends on 3) The method as claimed in claim 3, wherein a process for determining the individual weighting factor of the selected low-frequency partial image comprises: forming a quotient of an amplitude of a non-weighted partial image of the selected low-frequency partial image and the amplitude of the non-weighted low-frequency partial image having the next higher partial image frequency, setting the individual weighting factor of the selected low-frequency partial image to: a value of 1 if a last-cited quotient does not exceed the first ratio, or determine the individual weighting factor so that the quotient of the amplitude of the selected low-frequency partial image weighted with the individual weighting factor and the amplitude of the non-weighted low-frequency partial image having the next higher partial image frequency is identical with the first ratio if the last-cited quotient exceeds the first ratio. ### Claim 5 (depends on 2) The method as claimed in claim 2, wherein the first ratio is assigned to the computer by an operator and is between 1.5 and 2.5. ### Claim 6 (depends on 5) The method as claimed in claim 5, wherein the first ratio is between 1.8 and 2.2. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein a weighting factor of a selected high-frequency partial image is determined so that a quotient of amplitudes of two weighted high-frequency partial images whose partial image frequencies are directly adjacent is between a second and third ratio. ### Claim 8 (depends on 7) The method as claimed in claim 7, wherein an individual weighting factor of the selected high-frequency partial image is determined so that a quotient of an amplitude of a non-weighted high-frequency partial image having a next lower partial image frequency and an amplitude of the selected high-frequency partial image weighted with the individual weighting factor is between the second and third ratio, and wherein the weighting factor of the selected high-frequency partial image is determined by multiplying the individual weighting factor of the selected high-frequency partial image with a weighting factor of the pilot image and with individual weighting factors of remaining high-frequency partial images whose partial image frequencies are lower than a frequency of the selected high-frequency partial image. ### Claim 9 (depends on 8) The method as claimed in claim 8, wherein a process for determining the individual weighting factor of the selected high-frequency partial image comprises: forming a quotient of the amplitude of the non-weighted high-frequency partial image having the next lower partial image frequency and an amplitude of a non-weighted partial image of the selected high-frequency partial image, setting the individual weighting factor of the selected high-frequency partial image to: a value of 1 if a last-cited quotient is between the second and third ratio, or determine the individual weighting factor so that the quotient of the amplitude of the non-weighted high-frequency partial image having the next lower partial image frequency and the amplitude of the selected high-frequency partial image weighted with the individual weighting factor is identical with the second or the third ratio. ### Claim 10 (depends on 7) The method as claimed in claim 7, wherein the second and third ratio are assigned to the computer by an operator and the second ratio is between 1.5 and 2.0 and the third ratio is between 2.0 and 2.5. ### Claim 11 (depends on 1) The method as claimed in claim 1, wherein a weighting factor for the pilot image is determined so that an amplitude of a weighted pilot image is identical with a target amplitude. ### Claim 12 (depends on 11) The method as claimed in claim 11, wherein the target amplitude is assigned to the computer by an operator. ### Claim 13 (depends on 1) The method as claimed in claim 1, wherein the residual image contains: exclusively the direct component of the two-dimensional initial image which is locally invariable, or components of the two-dimensional initial image that vary locally with frequencies that are lower than a lowest partial image frequency in addition to the direct component of the two-dimensional initial image. ### Claim 14 (depends on 13) The method as claimed in claim 13, wherein a weighting factor of the residual image is determined as though the residual image were a low-frequency partial image whose partial image frequency is lower than frequencies of the partial image. ### Claim 15 (depends on 13) The method as claimed in claim 13, wherein an end factor is determined so that a mean value of the final image multiplied by the end factor equals a brightness value which is assigned to the computer by an operator. ### Claim 16 (depends on 13) The method as claimed in claim 13, wherein a weighting factor of the residual image which contains exclusively the direct component of the two-dimensional initial image is determined so that the direct component weighted with the weighting factor of the residual image equals a brightness value which is assigned to the computer by an operator. ### Claim 17 (depends on 1) The method as claimed in claim 1, wherein the target frequency is assigned to the computer by an operator and is between an eighth and half of the highest partial image frequency. ### Claim 18 A computer program stored on a computer readable medium for processing a two-dimensional initial image used in a medical procedure, comprising: a computer subroutine for disassembling the two-dimensional initial image into a plurality of partial images and a residual image by a computer, wherein each of the partial images contains a component of the two-dimensional initial image that varies locally with a predetermined partial image frequency departing from zero, wherein the residual image contains a direct component of the two-dimensional initial image that is locally invariable; a computer subroutine for assigning one of the partial images as a pilot image and assigning a frequency of the pilot image as a pilot frequency based on a comparison of frequencies of the partial images with a target frequency; a computer subroutine for determining a plurality of weighting factors for the partial images and the residual image; and a computer subroutine for summing the weighted partial images and the weighted residual image into a final image, wherein the computer determines the weighting factors of the partial images so that: the partial images with lower frequencies than the pilot frequency are weighted less than the pilot image but still contribute to the final image, the partial images with higher frequencies above the pilot frequency make: a large contribution to the final image when a noise component in the initial image is small, or a small contribution to the final image when the noise component in the initial image is large. ### Claim 19 A computer for processing a two-dimensional initial image used in a medical procedure, comprising: a hard drive storing a computer program, the computer program comprises: a computer subroutine for breaking down the two-dimensional initial image into a plurality of partial images and a residual image by the computer, wherein each of the partial images contains a component of the two-dimensional initial image that vary locally with a predetermined partial image frequency departing from zero, wherein the residual image contains a direct component of the two-dimensional initial image that is locally invariable; a computer subroutine for assigning one of the partial images as a pilot image and assigning a frequency of the pilot image as a pilot frequency based on a comparison of frequencies of the partial images with a target frequency; a computer subroutine for determining a plurality of weighting factors for the partial images and the residual image; and a computer subroutine for summing the weighted partial images and the weighted residual image into a final image, wherein the computer determines the weighting factors of the partial images so that: the partial images with lower frequencies than the pilot frequency are weighted less than the pilot image but still contribute to the final image, the partial images with higher frequencies above the pilot frequency make: a large contribution to the final image when a noise component in the initial image is small, or a small contribution to the final image when the noise component in the initial image is large.