# US 2026/0289798 A1 · Methods, a non-transitory computer readable memory and a device for updating a track of an object > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0289798 A1 - Document ID: US20260289798A1 - Status: Published application - Kind: A1 - Application number: 19/569,531 - Filed: 2026-03-17 - Published: 2026-09-24 - Earliest claimed: 2025-03-24 - Assignees: Axis AB - Applicants: Axis AB - Inventors: Jakob Hök; Andreas Jönsson - Web page: https://patentgrep.com/patent/US20260289798A1 ## CPC - G06T 7/246: using feature-based methods, e.g. the tracking of corners or segments - G06T 7/254: involving subtraction of images - G06T 7/277: involving stochastic approaches, e.g. using Kalman filters - G06T 7/73: using feature-based methods - G06T 2207/10016: Video; Image sequence - G06T 2207/30241: Trajectory - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract Methods and a device for updating a track of an object include first tracking of the object across a sequence of image frames preceding the current image frame using a first computer-implemented tracker. The tracker is updated based on object detections generated by a computer-implemented object detector executing an object detection algorithm. The first track includes an estimated object location for each frame in the subset. Using a motion model of the first tracker, a location of the object in the current image frame is predicted. Motion areas detected in the current image frame by a computer-implemented motion detection algorithm are then received. Based on the predicted location and the detected motion areas, the first tracker determines that a detected motion area corresponds to the object. The predicted location is updated based on the corresponding motion area, thereby determining an estimated location of the object in the current image frame. ## Claims ### Claim 1 A method for updating a track of an object in relation to a current image frame, comprising: determining, using a first computer implemented tracker, a first track of an object in a sequence of image frames preceding the current image frame, wherein the first computer implemented tracker is updated in at least a first subset of image frames of the sequence of image frames based on an object detection from a computer implemented object detector using an object detection algorithm, and wherein the first track includes a respective estimated location of the object in each image frame of the first subset of image frames of the sequence of image frames; predicting, using a motion model of the first computer implemented tracker, a location of the object in the current image frame; receiving, from a computer implemented motion detector using a motion detection algorithm, determined respective locations of detected motion areas in the current image frame; determining, using the first computer implemented tracker, based on the predicted location of the object in the current image frame, and the determined respective locations of the detected motion areas, that a detected motion area of the detected motion areas is associated with the object in the current image frame; and only on condition that the detected motion area determined to be associated with the object does not overlap a different track than the first track: updating, using the first computer implemented tracker, the predicted location of the object in the current image frame based on the determined location of the detected motion area determined to be associated with the object in the current image frame, thereby determining an estimated location of the object in the current image frame. ### Claim 2 (depends on 1) The method according to claim 1, wherein updating, using the first computer implemented tracker, the predicted location of the object in the current image based on the determined location of the detected motion area determined to be associated with the object in the current image frame is performed on condition that one or more of the following further criteria are fulfilled: the estimated location of the object in each of at least a first predetermined number of image frames of the sequence of image frames preceding the current image frame is not based on an object detection from the computer implemented object detector, a determined spatial confidence for the predicted location of the object in the current image frame is below a first spatial confidence threshold, and a determined velocity of the object for the current image frame is over a velocity threshold. ### Claim 3 (depends on 1) The method according to claim 1, further comprising: receiving, from the first computer implemented tracker, a predicted spatial extension of the object in the current image frame, wherein the predicted spatial extension together with the predicted location of the object in the current image frame determines an estimated object area of the object in the current image frame; determining, using the first computer implemented tracker, a spatial overlap between the detected motion area determined to be associated with the object in the current image frame and the estimated object area of the object in the current image frame, wherein in the act of updating, the degree to which the location of the detected motion area determined to be associated with the object in the current image frame is taken into account when updating the predicted location of the object in the current image frame is higher with higher determined spatial overlap. ### Claim 4 (depends on 1) The method according to claim 1, wherein the estimated location of the object in each image frame of the first subset of image frames of the sequence of image frames is determined by, for each image frame of the first subset of image frames of the sequence of image frames: predicting, using the motion model of the first computer implemented tracker, a location of the object in the image frame; detecting the object in the image frame using the computer implemented object detector; determining a location of the detected object in the image frame using the computer implemented object detector; and updating, using the first computer implemented tracker, the predicted location of the object in the image frame based on the determined location of the detected object in the image frame, thereby determining the estimated location of the object in the image frame. ### Claim 5 (depends on 1) The method according to claim 1, further comprising: detecting motion areas in the current image frame using the computer implemented motion detector; determining respective locations of the detected motion areas in the current image frame using the computer implemented motion detector; and providing the determined respective locations of the detected motion areas in the current image frame to the first computer implemented tracker. ### Claim 6 (depends on 1) The method according to claim 1, further comprising: on condition that: there are two or more object detections in the current image from the computer implemented object detector which can be associated with the object in the current image frame; there is a second track in the sequence of image frames preceding the current image frame determined using a second computer implemented tracker, wherein the second computer implemented tracker is updated in at least a second subset of image frames of the sequence of image frames based on motion detection from the computer implemented motion detector; the second track is associated with the first track; and the second track is not the result of a split of a track into two tracks or a merge of two tracks into one track within a second predetermined number of image frames of the second subset of image frames of the sequence of image frames preceding the current image frame, preventing updating, using the first computer implemented tracker, the predicted location of the object in the current image frame based on an estimated location of a detected object in the current image frame. ### Claim 7 A method for updating a track of an object in relation to a current image frame, comprising: determining, using a first computer implemented tracker, a first track of an object in a sequence of image frames preceding the current image frame, wherein the first computer implemented tracker is updated in at least a first subset of image frames of the sequence of image frames based on an object detection from a computer implemented object detector using an object detection algorithm, and wherein the first track includes a respective estimated location of the object in each image frame of the first subset of image frames of the sequence of image frames; predicting, using a motion model of the first computer implemented tracker, a location in the first track of the object in the current image frame; determining that a second track is associated with the first track, wherein the second track is determined in the sequence of image frames preceding the current using a second computer implemented tracker, wherein the second computer implemented tracker is updated in at least a second subset of image frames of the sequence of image frames based on motion detection from a computer implemented motion detector using a motion detection algorithm; receiving, from the second computer implemented tracker, an estimated location in the second track of the object in the current image frame; and only on condition that the estimated location in the second track of the object in the current image frame does not overlap a different track than the first track in the current image frame: updating, using the first computer implemented tracker, the predicted location of the object in the current image frame based on the received estimated location in the second track of the object in the current image frame, thereby determining an estimated location in the first track of the object in the current image frame. ### Claim 8 (depends on 7) The method according to claim 7, wherein updating, using the first computer implemented tracker, the predicted location of the object in the current image based on the received estimated location in the second track of the object in the current image frame is performed on condition that one or more of the following further criteria are fulfilled: the estimated location of the object in each of at least a first predetermined number of image frames of the sequence of image frames preceding the current image frame is not based on an object detection from the computer implemented object detector, a determined spatial confidence for the predicted location of the object in the current image frame is below a first spatial confidence threshold, and a determined velocity of the object for the current image frame is over a velocity threshold. ### Claim 9 (depends on 7) The method according to claim 7, further comprising: receiving, from the first computer implemented tracker, a predicted spatial extension in the first track of the object in the current image frame, wherein the predicted spatial extension in the first track of the object in the current image frame together with the predicted location in the first track of the object in the current image frame determines a predicted object area in the first track of the object in the current image frame; receiving, from the second computer implemented tracker, an estimated spatial extension in the second track of the object in the current image frame, wherein the estimated spatial extension in the second track of the object in the current image frame together with the estimated location in the second track of the object in the current image frame determines an estimated object area in the second track of the object in the current image frame; determining, using the first computer implemented tracker, a spatial overlap between the estimated object area in the second track of the object in the current image frame and the predicted object area in the first track of the object in the current image frame, wherein in the act of updating, the degree to which the estimated location in the second track of the object in the current image frame is taken into account when updating the predicted location in the first track of the object in the current image frame is higher with higher determined spatial overlap. ### Claim 10 (depends on 7) The method according to claim 7, wherein, for the first computer implemented tracker, the estimated location of the object in each image frame of the first subset of image frames of the sequence of image frames is determined by, for each image frame of the first subset of image frames of the sequence of image frames: predicting, using the motion model of the first computer implemented tracker, a location of the object in the image frame; detecting the object in the image frame using the computer implemented object detector; determining a location of the detected object in the image frame using the computer implemented object detector; and updating, using the first computer implemented tracker, the predicted location of the object in the image frame based on the determined location of the detected object in the image frame, thereby determining the estimated location in the first track of the object in the image frame. ### Claim 11 (depends on 7) The method according to claim 7, wherein, for the second computer implemented tracker, the estimated location of the object in each image frame of the second subset of image frames of the sequence of image frames is determined by, for each image frame of the second subset of image frames of the sequence of image frames: predicting, using a motion model of the second computer implemented tracker, a location of the object in the image frame; detecting a motion area in the image frame using the computer implemented motion detector; determining a location of the detected motion area in the image frame using the computer implemented motion detector; and updating, using the second computer implemented tracker, the predicted location of the object in the image frame based on the determined location of the detected motion area in the image frame, thereby determining the estimated location in the second track of the object in the image frame. ### Claim 12 (depends on 7) The method according to claim 7, further comprising: on condition that: there are two or more object detections having a spatial overlap with the predicted location in the first track of the object in the current image frame indicating association; the second track is associated with the first track; and the second track is not the result of a split or a merge within a third predetermined number of image frames of the second subset of image frames of the sequence of image frames preceding the current image frame, preventing updating, using the first computer implemented tracker, the predicted location of the object in the current image frame based on a determined location of a detected object in the current image frame. ### Claim 13 A non-transitory computer-readable medium comprising computer program code which, when executed by a device with processing capability, causes the device to carry out a method for updating a track of an object in relation to a current image frame, comprising: determining, using a first computer implemented tracker, a first track of an object in a sequence of image frames preceding the current image frame, wherein the first computer implemented tracker is updated in at least a first subset of image frames of the sequence of image frames based on an object detection from a computer implemented object detector using an object detection algorithm, and wherein the first track includes a respective estimated location of the object in each image frame of the first subset of image frames of the sequence of image frames; predicting, using a motion model of the first computer implemented tracker, a location of the object in the current image frame; receiving, from a computer implemented motion detector using a motion detection algorithm, determined respective locations of detected motion areas in the current image frame; determining, using the first computer implemented tracker, based on the predicted location of the object in the current image frame, and the determined respective locations of the detected motion areas, that a detected motion area of the detected motion areas is associated with the object in the current image frame; and only on condition that the detected motion area determined to be associated with the object does not overlap a different track than the first track: updating, using the first computer implemented tracker, the predicted location of the object in the current image frame based on the determined location of the detected motion area determined to be associated with the object in the current image frame, thereby determining an estimated location of the object in the current image frame. ### Claim 14 (depends on 1) A device for updating a track of an object in relation to a current image frame, comprising circuitry configured to execute functions for performing the method according to claim 1.