# US 9,521,326 B2 · Misregistration correction using non-pinhole camera model and non-linear scan equations > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,521,326 B2 - Document ID: US9521326B2 - Status: Granted - Kind: B2 - Application number: 14/272,151 - Filed: 2014-05-07 - Published: 2014-11-13 - Granted: 2016-12-13 - Earliest claimed: 2013-05-08 - Assignees: Raytheon Company - Applicants: Raytheon Company - Inventors: Sarah A. LaFarelle; Archie Henry Muse - Web page: https://patentgrep.com/patent/US9521326B2 ## CPC - H04N 23/683: {performed by a processor, e.g. controlling the readout of an image memory} - G01C 11/025: {by scanning the object} - G06T 5/73: Deblurring; Sharpening - G06T 5/80: Geometric correction - G06T 7/246: using feature-based methods, e.g. the tracking of corners or segments - H04N 23/6811: {based on the image signal} - H04N 25/71: Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors - G06T 2207/20201: Motion blur correction - G06T 2207/30241: Trajectory - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A method of misregistration correction in a line scanning imaging system includes: generating a model of scan motion over a focal plane of the imaging system, using a coupled system of non-linear scan equations with constant coefficients; estimating programmed motion positions across a plurality of detector junction overlap regions via a state transition matrix solution to the scan equations; at each detector junction overlap region, measuring actual motion positions via image correlation of overlapping detectors; generating differences between the actual motion positions and the estimated programmed motion positions; estimating updates to the constant coefficients based on the generated differences; generating corrections from the estimated updates to remove unwanted motion; and applying the updates to the constant coefficients. ## Claims ### Claim 1 A method of misregistration correction in a line scanning imaging system, comprising: providing the line scanning imaging system with a forward array of optical detectors and a trailing array of optical detectors for receiving optical signals from a scene being scanned and converting the optical signals into electrical signals, the forward array of optical detectors receiving the optical signals at a different time than the trailing array of optical detectors receiving the optical signals, the forward array of optical detectors and the trailing array of optical detectors defining a plurality of detector junction overlap regions; receiving the electrical signals at a processor; processing the received electrical signals with the processor, the processing comprising the steps of: generating a model of scan motion over a focal plane of the imaging system, using a coupled system of non-linear scan equations with constant coefficients; estimating programmed motion positions across the plurality of detector junction overlap regions via a state transition matrix solution to the non-linear scan equations; at each detector junction overlap region, measuring actual motion positions via image correlation of overlapping detectors; generating differences between the actual motion positions and the estimated programmed motion positions; estimating updates to the constant coefficients based on the generated differences; generating corrections from the estimated updates to remove unwanted motion; and applying the updates to the constant coefficients; wherein the steps of generating a model of scan motion, estimating programmed motion positions, measuring actual motion positions, generating differences, estimating updates, generating corrections and applying the updates are performed by means of a non-transitory computer-usable medium having computer-readable code that, when executed by the processor, cause the processor to perform the steps. ### Claim 2 (depends on 1) The method of claim 1, wherein estimating updates is performed using least-squares estimation. ### Claim 3 (depends on 1) The method of claim 1, wherein the image correlation comprises normalized cross-correlation. ### Claim 4 (depends on 1) The method of claim 1, wherein the image correlation comprises lag product cross-correlation. ### Claim 5 (depends on 1) The method of claim 1, wherein the image correlation comprises least squares cross-correlation. ### Claim 6 (depends on 1) The method of claim 1, wherein the model of scan motion is generated over a predetermined time interval. ### Claim 7 (depends on 1) The method of claim 1, wherein the non-linear scan equations comprise a set of differential equations with constant coefficients. ### Claim 8 (depends on 7) The method of claim 7, wherein the differential equations are first-order differential equations. ### Claim 9 (depends on 1) The method of claim 1, further comprising computing the non-linear scan equation coefficients using sensor platform parameters. ### Claim 10 (depends on 9) The method of claim 9, wherein the sensor platform parameters comprise at least one of sensor position, velocity, attitude angles and rates. ### Claim 11 (depends on 10) The method of claim 10, further comprising approximating errors in the non-linear scan equation coefficients from measurement errors in the platform parameters. ### Claim 12 (depends on 11) The method of claim 11, further comprising generating a covariance matrix of focal plane coordinate errors. ### Claim 13 (depends on 10) The method of claim 10, further comprising estimating platform parameter errors from the differences between the actual motion positions and the estimated programmed motion positions.