# US 2021/0241419 A1 · Control method for image projection system, and image projection system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0241419 A1 - Document ID: US20210241419A1 - Status: Published application - Kind: A1 - Application number: 17/162,725 - Filed: 2021-01-29 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Taisuke YAMAUCHI - Web page: https://patentgrep.com/patent/US20210241419A1 ## CPC - G06T 3/08: Projecting images onto non-planar surfaces, e.g. geodetic screens - G06T 3/06: Topological mapping of higher dimensional structures onto lower dimensional surfaces - G06T 5/80: Geometric correction - G06T 7/521: from laser ranging, e.g. using interferometry; from the projection of structured light - G06T 11/00: Two-dimensional [2D] image generation - G06T 15/00: Three-dimensional [3D] image rendering - H04N 9/3147: {Multi-projection systems (video walls G06F3/1446)} - H04N 9/3185: {Geometric adjustment, e.g. keystone or convergence (optical or mechanical adjustment of convergence H04N9/317; using scanning means H04N3/22; optical or mechanical adjustments of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/14)} - H04N 9/3194: {including sensor feedback} - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A projector includes a correction information generation unit, image information correction unit, and image projection unit. The generation unit sets a first coordinate in a two-dimensional projection formed by flattening out a three-dimensional projection surface onto a plane. The generation unit arranges a first quadrilateral having a first aspect ratio within the two-dimensional projection, based on the first coordinate as a reference position, so that the first quadrilateral comes into contact with an outline of the two-dimensional projection. The generation unit determines whether the first quadrilateral is in contact with the outline at two or more points. When the first quadrilateral is determined as being in contact with the outline at two or more points, the correction unit corrects image information, based on the first quadrilateral, and thus generates corrected image information. The image projection unit projects an image based on the corrected image information onto the projection surface. ## Claims ### Claim 1 A control method for an image projection system, the control method comprising: setting a first coordinate in a two-dimensional projection formed by flattening out a three-dimensional projection surface onto a plane; arranging a first quadrilateral having a first aspect ratio within the two-dimensional projection, based on the first coordinate as a reference position, in such a way that the first quadrilateral comes into contact with an outline of the two-dimensional projection; determining whether the first quadrilateral is in contact with the outline of the two-dimensional projection at two or more points, or not; correcting a image information, based on the first quadrilateral, and thus generating the corrected image information, when the first quadrilateral is determined as being in contact with the outline of the two-dimensional projection at two or more points; and projecting an image based on the corrected image information onto the projection surface. ### Claim 2 (depends on 1) The control method for the image projection system according to claim 1, wherein when the first quadrilateral is determined as not being in contact with the outline of the two-dimensional projection at two or more points, the first coordinate is changed, then the first quadrilateral is arranged within the two-dimensional projection, based on the changed first coordinate as a reference position, in such away that the first quadrilateral comes into contact with the outline of the two-dimensional projection, and whether the first quadrilateral is in contact with the outline of the two-dimensional projection at two or more points, or not, is determined again. ### Claim 3 (depends on 1) The control method for the image projection system according to claim 1, wherein when the first quadrilateral is determined as not being in contact with the outline of the two-dimensional projection at two or more points, a minimum distance along a first axis and a minimum distance along a second axis intersecting the first axis between the first quadrilateral and the outline of the two-dimensional projection are calculated, and the first coordinate is changed, based on the minimum distance along the first axis and the minimum distance along the second axis, and the first quadrilateral is arranged within the two-dimensional projection, based on the changed first coordinate as a reference position, in such a way that the first quadrilateral comes into contact with the outline of the two-dimensional projection, and whether the first quadrilateral is in contact with the outline of the two-dimensional projection at two or more points, or not, is determined again. ### Claim 4 (depends on 1) The control method for the image projection system according to claim 1, wherein a coordinate of a center position of the two-dimensional projection or a coordinate of a centroid position of the two-dimensional projection is decided as the first coordinate. ### Claim 5 (depends on 1) The control method for the image projection system according to claim 1, wherein a second quadrilateral having the first aspect ratio and circumscribing the two-dimensional projection is arranged, based on the first coordinate as a reference position, and the first quadrilateral is generated by reducing the second quadrilateral while maintaining the first aspect ratio. ### Claim 6 (depends on 1) The control method for the image projection system according to claim 1, wherein a pattern image is projected on the projection surface, and a three-dimensional shape of the projection surface is measured, based on picked-up image information generated by picking up an image of the projection surface where the pattern image is projected. ### Claim 7 (depends on 1) The control method for the image projection system according to claim 1, wherein the image projection system includes a first projection device and a second projection device, and the projection surface is acquired by coupling together a first projection surface where an image is projected by the first projection device and a second projection surface where an image is projected by the second projection device. ### Claim 8 An image projection system comprising: a correction device generating corrected image information; and a projection device projecting an image based on the corrected image information onto a projection surface, wherein the correction device sets a first coordinate in a two-dimensional projection formed by flattening out a three-dimensional projection surface onto a plane, and arranges a first quadrilateral having a first aspect ratio within the two-dimensional projection, based on the first coordinate as a reference position, in such a way that the first quadrilateral comes into contact with an outline of the two-dimensional projection, determines whether the first quadrilateral is in contact with the outline of the two-dimensional projection at two or more points, or not, and corrects a image information, based on the first quadrilateral, and thus generates the corrected image information, when the first quadrilateral is determined as being in contact with the outline of the two-dimensional projection at two or more points. ### Claim 9 (depends on 8) The image projection system according to claim 8, further comprising: an image pickup device picking up an image of a pattern image projected on the projection surface by the projection device and thus generating picked-up image information; and a measuring device measuring a three-dimensional shape of the projection surface, based on the picked-up image information. ### Claim 10 (depends on 9) The image projection system according to claim 9, wherein the image pickup device, the projection device, and the measuring device are formed as a unified structure.