Image processing system, projector, program, information storage medium and image processing method

• US 20050036117A1
• Filed: 06/16/2004
• Published: 02/17/2005
• Est. Priority Date: 07/11/2003
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kobayashi, Masanobu
• Granted Patent: US 7,470,029 B2
• Time in Patent Office: Days
• US Class Current: 353/70
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: 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
• CPC Class Codes: H04N 9/3194 including sensor feedback

Abstract

To provide an image processing system and the like which can correct a distortion of a projected image through only a single sensor, a projector has a calibration image information generating section which generates image information used to display a rectangular calibration image; an image projection section which projects the calibration image onto a projection target, based on the image information; a sensing section which senses a region including the projected calibration image plane and generates sensing information; a projection area information generating section which generates shortest-distance projection area information based on the sensing information in such a state that a distance between the projection section and the projection target is different from the distance in an actual operating condition, and generates actual projection area information based on the sensing information in the actual operating condition; and a correction information generating section which generates image distortion correction information, based on the shortest-distance projection area information and actual projection area information.

Claims

1. An image processing system comprising:

a calibration image information generating means for generating image information used to display a rectangular calibration image;

a projection means for projecting the calibration image onto a projection target, based on the image information;

a sensing means for sensing a region including the projected calibration image through a sensing plane and generating sensing information;

a projection area information generating means for generating temporary projection area information which indicates coordinates of four corners of the calibration image on the sensing plane, based on the sensing information in such a state that an entire portion of the calibration image is included within a sensing range of the sensing means and under such a state that a distance between the projection means and the projection target is different from the distance in an actual operating condition, and for generating actual projection area information which indicates the coordinates of the four corners of the calibration image in the sensing plane, based on the sensing information in the actual operating condition;

a correction information generating means for generating image distortion correction information; and

a distortion correction means for correcting a distortion of the image, based on the image distortion correction information,

wherein the correction information generating means has following functions of;

deriving an inter-coordinate distance between each of the coordinates of the four corners included in the temporary projection area information and corresponding one of the coordinates of the four corners included in the actual projection area information;

deriving a projection distance on an optical axis of the projection means between the projection means and each of the four corners of the calibration image on the projection target, based on projection distance data in which the inter-coordinate distance is associated with the projection distance and based on the inter-coordinate distance;

deriving three-dimensional coordinates of at least three of the four corners of the calibration image in a three-dimensional space for the projection means to process an image, based on the projection distance and the half angle-of-view in the projection means;

deriving an angle formed by the optical axis of the projection means and the projection target, based on the three-dimensional coordinates; and

generating the image distortion correction information, based on the derived angle.

2. The image processing system as defined in claim 1, wherein the correction information generating means has following functions of:

deriving a normal vector in the projection target, based on the three-dimensional coordinates; and

deriving an angle formed by the optical axis of the projection means and the projection target, based on the normal vector and a directional vector of the optical axis of the projection means.

3. An image processing system comprising:

a calibration image information generating section which generates image information used to display a rectangular calibration image;

a projection section which projects the calibration image onto a projection target, based on the image information;

a sensing section which senses a region including the projected calibration image through a sensing plane and generates sensing information;

a projection area information generating section which generates temporary projection area information which indicates coordinates of four corners of the calibration image on the sensing plane, based on the sensing information in such a state that an entire portion of the calibration image is included within a sensing range of the sensing section and under such a state that a distance between the projection section and the projection target is different from the distance in an actual operating condition, and generates actual projection area information which indicates the coordinates of the four corners of the calibration image in the sensing plane, based on the sensing information in the actual operating condition;

a correction information generating section which generates image distortion correction information; and

a distortion correction section which corrects a distortion of the image, based on the image distortion correction information,

wherein the correction information generating section has following functions of;

deriving an inter-coordinate distance between each of the coordinates of the four corners included in the temporary projection area information and corresponding one of the coordinates of the four corners included in the actual projection area information;

deriving a projection distance on an optical axis of the projection section between the projection section and each of the four corners of the calibration image on the projection target, based on projection distance data in which the inter-coordinate distance is associated with the projection distance and based on the inter-coordinate distance;

deriving three-dimensional coordinates of at least three of the four corners of the calibration image in a three-dimensional space for the projection section to process an image, based on the projection distance and the half angle-of-view in the projection section;

deriving an angle formed by the optical axis of the projection section and the projection target, based on the three-dimensional coordinates; and

generating the image distortion correction information, based on the derived angle.

4. A projector comprising:

a calibration image information generating means for generating image information used to display a rectangular calibration image;

a projection means for projecting the calibration image onto a projection target, based on the image information;

a sensing means for sensing a region including the projected calibration image through a sensing plane and generating sensing information;

a projection area information generating means for generating temporary projection area information which indicates coordinates of four corners of the calibration image on the sensing plane, based on the sensing information in such a state that an entire portion of the calibration image is included within a sensing range of the sensing means and under such a state that a distance between the projection means and the projection target is different from the distance in an actual operating condition, and for generating actual projection area information which indicates the coordinates of the four corners of the calibration image in the sensing plane, based on the sensing information in the actual operating condition;

a correction information generating means for generating image distortion correction information; and

a distortion correction means for correcting a distortion of the image, based on the image distortion correction information,

wherein the correction information generating means has following functions of;

deriving an inter-coordinate distance between each of the coordinates of the four corners included in the temporary projection area information and corresponding one of the coordinates of the four corners included in the actual projection area information;

deriving a projection distance on an optical axis of the projection means between the projection means and each of the four corners of the calibration image on the projection target, based on projection distance data in which the inter-coordinate distance is associated with the projection distance and based on the inter-coordinate distance;

deriving three-dimensional coordinates of at least three of the four corners of the calibration image in a three-dimensional space for the projection means to process an image, based on the projection distance and the half angle-of-view in the projection means;

deriving an angle formed by the optical axis of the projection means and the projection target, based on the three-dimensional coordinates; and

generating the image distortion correction information, based on the derived angle.

5. A projector comprising:

a calibration image information generating section which generates image information used to display a rectangular calibration image;

a projection section which projects the calibration image onto a projection target, based on the image information;

a sensing section which senses a region including the projected calibration image through a sensing plane and generates sensing information;

a projection area information generating section which generates temporary projection area information which indicates coordinates of four corners of the calibration image on the sensing plane, based on the sensing information in such a state that an entire portion of the calibration image is included within a sensing range of the sensing section and under such a state that a distance between the projection section and the projection target is different from the distance in an actual operating condition, and generates actual projection area information which indicates the coordinates of the four corners of the calibration image in the sensing plane, based on the sensing information in the actual operating condition;

a correction information generating section which generates image distortion correction information; and

a distortion correction section which corrects a distortion of the image, based on the image distortion correction information,

wherein the correction information generating section has following functions of;

deriving an inter-coordinate distance between each of the coordinates of the four corners included in the temporary projection area information and corresponding one of the coordinates of the four corners included in the actual projection area information;

deriving a projection distance on an optical axis of the projection section between the projection section and each of the four corners of the calibration image on the projection target, based on projection distance data in which the inter-coordinate distance is associated with the projection distance and based on the inter-coordinate distance;

deriving three-dimensional coordinates of at least three of the four corners of the calibration image in a three-dimensional space for the projection section to process an image, based on the projection distance and the half angle-of-view in the projection section;

deriving an angle formed by the optical axis of the projection section and the projection target, based on the three-dimensional coordinates; and

generating the image distortion correction information, based on the derived angle.

6. A computer-readable program which causes a computer to function as:

a calibration image information generating means for generating image information used to display a rectangular calibration image;

a projection means for projecting the calibration image onto a projection target, based on the image information;

a sensing means for sensing a region including the projected calibration image through a sensing plane and generating sensing information;

a projection area information generating means for generating temporary projection area information which indicates coordinates of four corners of the calibration image on the sensing plane, based on the sensing information in such a state that an entire portion of the calibration image is included within a sensing range of the sensing means and under such a state that a distance between the projection means and the projection target is different from the distance in an actual operating condition, and for generating actual projection area information which indicates the coordinates of the four corners of the calibration image in the sensing plane, based on the sensing information in the actual operating condition;

a correction information generating means for generating image distortion correction information; and

a distortion correction means for correcting a distortion of the image, based on the image distortion correction information,

wherein the correction information generating means has following functions of;

deriving an inter-coordinate distance between each of the coordinates of the four corners included in the temporary projection area information and corresponding one of the coordinates of the four corners included in the actual projection area information;

deriving a projection distance on an optical axis of the projection means between the projection means and each of the four corners of the calibration image on the projection target, based on projection distance data in which the inter-coordinate distance is associated with the projection distance and based on the inter-coordinate distance;

deriving three-dimensional coordinates of at least three of the four corners of the calibration image in a three-dimensional space for the projection means to process an image, based on the projection distance and the half angle-of-view in the projection means;

deriving an angle formed by the optical axis of the projection means and the projection target, based on the three-dimensional coordinates; and

generating the image distortion correction information, based on the derived angle.

7. An information storage medium storing a computer-readable program which causes a computer to function as:

a calibration image information generating means for generating image information used to display a rectangular calibration image;

a projection means for projecting the calibration image onto a projection target, based on the image information;

a sensing means for sensing a region including the projected calibration image through a sensing plane and generating sensing information;

a projection area information generating means for generating temporary projection area information which indicates coordinates of four corners of the calibration image on the sensing plane, based on the sensing information in such a state that an entire portion of the calibration image is included within a sensing range of the sensing means and under such a state that a distance between the projection means and the projection target is different from the distance in an actual operating condition, and for generating actual projection area information which indicates the coordinates of the four corners of the calibration image in the sensing plane, based on the sensing information in the actual operating condition;

a correction information generating means for generating image distortion correction information; and

a distortion correction means for correcting a distortion of the image, based on the image distortion correction information,

wherein the correction information generating means has following functions of;

deriving an inter-coordinate distance between each of the coordinates of the four corners included in the temporary projection area information and corresponding one of the coordinates of the four corners included in the actual projection area information;

deriving a projection distance on an optical axis of the projection means between the projection means and each of the four corners of the calibration image on the projection target, based on projection distance data in which the inter-coordinate distance is associated with the projection distance and based on the inter-coordinate distance;

deriving three-dimensional coordinates of at least three of the four corners of the calibration image in a three-dimensional space for the projection means to process an image, based on the projection distance and the half angle-of-view in the projection means;

deriving an angle formed by the optical axis of the projection means and the projection target, based on the three-dimensional coordinates; and

generating the image distortion correction information, based on the derived angle.

8. An image processing method comprising:

causing an image projection device to project a rectangular calibration image onto a projection target, sensing a region including the projected calibration image through a sensing plane, and generating first projection area information which indicates coordinates of four corners of the calibration image in the sensing plane, when a positional relationship between the image projection device and the projection target becomes a first state in which an entire portion of the calibration image is included within a sensing range;

causing the image projection device to project the calibration image onto the projection target, sensing the region including the projected calibration image through the sensing plane, and generating second projection area information which indicates the coordinates of the four corners of the calibration image in the sensing plane, when the positional relationship between the image projection device and the projection target becomes a second state in which an entire portion of the rectangular calibration image is included within the sensing range, the second state being different from the first state;

deriving an inter-coordinate distance between each of the coordinates of the four corners included in the first projection area information and the corresponding one of the coordinates of the four corners included in the second projection area information;

deriving a projection distance on an optical axis of a projected light between the image projection device and each of the coordinates of the four corners of the calibration image on the projection target, based on the projection distance data in which the inter-coordinate distance is associated with the projection distance and based on the inter-coordinate distance;

deriving three-dimensional coordinates of at least three of the four corners of the calibration image in a three-dimensional space for the image projecting device to process an image, based on the projection distance and the half angle-of-view in the projected light;

deriving an angle formed by the optical axis of the projected light and the projection target, based on the three-dimensional coordinates;

generating image distortion correction information, based on the derived angle; and

correcting image distortion, based on the generated image distortion correction information.

9. The image processing method as defined in claim 8, when the angle formed by the optical axis of the projected light and the projection target is derived, the method comprising:

deriving a normal vector in the projection target, based on the three-dimensional coordinates; and

deriving an angle formed by the optical axis of the projected light and the projection target, based on the normal vector and a directional vector of the optical axis of the projected light.