# US 2010/0166286 A1 · Motion artefact reduction in CT scanning > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0166286 A1 - Document ID: US20100166286A1 - Status: Published application - Kind: A1 - Application number: 12/601,442 - Filed: 2007-05-31 - Published: 2010-07-01 - Earliest claimed: 2007-05-31 - Assignees: Elekta AB (publ) - Inventors: Jan-Jakob Sonke; Marcel van Herk; Peter Remeijer - Web page: https://patentgrep.com/patent/US20100166286A1 ## CPC - G06T 7/20: Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51) - G06T 5/73: Deblurring; Sharpening - G06T 2207/10116: X-ray image - G06T 2207/20068: Projection on vertical or horizontal image axis - G06T 2207/30004: Biomedical image processing - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract An example of sporadic motion that causes difficulty in CT scanning is gas pockets moving around the rectum. The invention allows the automatic detection of such movements, by enhancing low density features around the prostate in the individual X-ray images, projecting these features on the cranio-caudal axis (assuming that the gas predominantly moves in this direction) to form a 1-dimensional image, and combining successive ID projections to form a 2D image. Moving gas will produce tilted lines in this image, identifying an angular range that needs to be discarded. Such a process can be used in an image processing apparatus of a CT scanner. ## Claims ### Claim 1 An image processing method comprising the steps of; gathering a collection of two-dimensional x-ray images of a subject, ordered in time sequence; for each image of the collection, projecting at least part of the image to a projection axis, to derive a collection of one-dimensional images aligned with the projection axis and whose pixel values represent a sum of pixel values in the respective two-dimensional image transverse to the projection axis; assembling the one-dimensional images to form a single two dimensional image having a spatial dimension aligned with the projection axis and a time dimension transverse to the projection axis; detecting features that are tilted in the two dimensional image with respect to the time and spatial dimensions. ### Claim 2 (depends on 1) The image processing method according to claim 1 in which a new collection is subsequently prepared, being the original collection after deletion of at least the images contributing to the tilted features. ### Claim 3 (depends on 1) The image processing method according to claim 1 in which a new collection is subsequently prepared, being original collection after removal of the subset containing images prior to and contributing to the tilted features. ### Claim 4 (depends on 1) The image processing method according to claim 1 in which a new collection is subsequently prepared, being original collection after removal of the subset containing images subsequent to and contributing to the tilted features. ### Claim 5 (depends on 1) The image processing method according to claim 1 in which the whole of the image is projected. ### Claim 6 (depends on 1) The image processing method according to claim 1 in which the images of the collection comprise images of substantially the same subject albeit from different viewpoints. ### Claim 7 (depends on 6) The image processing method according to claim 6 in which the different viewpoints comprise views along a plurality of directions in substantially the same plane, the plurality of directions converging on an image axis transverse to the plane. ### Claim 8 (depends on 7) The image processing method according to claim 7 in which the image axis is parallel to the projection axis. ### Claim 9 (depends on 7) The image processing method according to claim 7 in which the image axis is coincident with the projection axis. ### Claim 10 (depends on 1) The image processing method according to claim 1 in which the projection step involves summing the total pixel value along a direction transverse to the projection axis. ### Claim 11 (depends on 10) The image processing method according to claim 10 in which the total pixel value is then normalised. ### Claim 12 (depends on 10) The image processing method according to claim 10 in which the projection axis is parallel to an edge of the image. ### Claim 13 (depends on 1) The image processing method according to claim 1 in which the subject of the images is a patient. ### Claim 14 (depends on 13) The image processing method according to claim 13 in which the images include the prostate region of the patient. ### Claim 15 (depends on 13) The image processing method according to claim 13 in which the projection axis is aligned with the craniocordal axis of the patient. ### Claim 16 An image processing apparatus containing a computing means adapted to perform the process comprising: gathering a collection of two-dimensional x-ray images of a subject, ordered in time sequence; for each image of the collection, projecting at least part of the image to a projection axis, to derive a collection of one-dimensional images aligned with the projection axis and whose pixel values represent a sum of pixel values in the respective two-dimensional image transverse to the projection axis; assembling the one-dimensional images to form a single two dimensional image having a spatial dimension aligned with the projection axis and a time dimension transverse to the projection axis; detecting features that are tilted in the two dimensional image with respect to the time and spatial dimensions. ### Claim 17 A CT scanner containing an image processing apparatus adapted to perform the process comprising: gathering a collection of two-dimensional x-ray images of a subject, ordered in time sequence; for each image of the collection, projecting at least part of the image to a projection axis to derive a collection of one-dimensional images aligned with the projection axis and whose pixel values represent a sum of pixel values in the respective two-dimensional image transverse to the projection axis; assembling the one-dimensional images to form a single two dimensional image having a spatial dimension aligned with the projection axis and a time dimension transverse to the projection axis; detecting features that are tilted in the two dimensional image with respect to the time and spatial dimensions. ### Claim 18 (canceled)