Projector with a plurality of cameras

• US 20050179875A1
• Filed: 02/10/2005
• Published: 08/18/2005
• Est. Priority Date: 02/13/2004
• Status: Active Grant

• Current Assignee: NEC Display Solutions, Ltd. (NEC Corporation)
• Original Assignee: NEC Viewtechnology, Ltd.
• Inventors: Aoyanagi, Hisakazu
• Granted Patent: US 7,226,173 B2
• Time in Patent Office: Days
• US Class Current: 353/101
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G03B 21/142 Adjusting of projection optics
• CPC Class Codes: G03B 5/02 Lateral adjustment of lens
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/243 using three or more 2D image sensors
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals
• 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

A projector has a plurality of cameras for adjusting the focus of projected images, correcting projected images that are distorted when images are projected from the projector when it swings from side to side and tilts or when images are projected onto a shaped surface of a projection object, and correcting projected images so that to match the outer profile of the screen if the screen is used as a projection object. The projector has a projection device having a projection lens, a focus adjuster for adjusting the focus of the projection lens, a zoom adjuster for adjusting the zooming of the projection lens, an imager having a plurality of cameras for capturing respective images of a projection object, a projection area calculator for calculating a projection area of an image depending on the distance from the projection lens based on the zoomed position from the zoom adjuster, a three-dimensional position detector for detecting the three-dimensional position of a predetermined object point corresponding to identical object points in the respective images captured by the cameras from the images captured by the cameras and the projection area of the image calculated by the projection area calculator, and a distance detector for detecting the distance up to the object point from the three-dimensional position of the predetermined object point.

Claims

1. A projector comprising:

a projection device having a projection lens;

a focus adjuster for adjusting the focus of said projection lens;

a zoom adjuster for adjusting the zooming of said projection lens;

an imager having a plurality of cameras for capturing respective images of a projection object;

a projection area calculator for calculating a projection area of an image depending on a distance from the projection lens based on a zoomed position from said zoom adjuster;

a three-dimensional position detector for detecting a three-dimensional position of a predetermined object point corresponding to identical object points in the respective images captured by said cameras from the images captured by said cameras and the projection area of the image calculated by said projection area calculator; and

a distance detector for detecting the distance up to the object point from the three-dimensional position of said predetermined object point.

2. A projector according to claim 1, wherein said object point comprises a predetermined pattern projected from said projection device onto said projection object near a central area thereof, and the focus of said projection lens is adjusted by said focus adjuster based on the distance up to the object point which is detected by said distance detector.

3. A projector according to claim 1, further comprising:

a projection surface detector for detecting distances up to said object points from the three-dimensional positions of a plurality of said predetermined object points which are detected by said three-dimensional position detector and arranging the detected distances two-dimensionally;

wherein said object points comprise a plurality of patterns projected in a plane onto said projection object by said projection device;

said distance detector calculates an average distance based on the distances up to said object points which are detected by said projection surface detector; and

said focus adjuster adjusts the focus of said projection lens based on the calculated average distance.

4. A projector according to claim 3, further comprising:

an image controller for controlling a projected image; and

a distortion correction calculator for calculating a corrective value for correcting a projected image that is distorted;

wherein said distortion correction calculator calculates a distortion correction coefficient for correcting a distortion of said projected image based on the difference between the distances that are based on the distances up to said object points which are detected by said projection surface detector; and

said image controller corrects the projected image inputted to said projection device based on said distortion correction coefficient.

5. A projector according to claim 1, further comprising:

an image controller for controlling a projected image;

a projection surface detector for detecting distances up to said object points from the three-dimensional positions of a plurality of said predetermined object points which are detected by said three-dimensional position detector and arranging the detected distances two-dimensionally; and

a distortion correction calculator for calculating a corrective value for correcting a projected image that is distorted,

wherein said projection object comprises a screen, said object points comprise a boundary line between said screen and a background scene and an outer profile of said projected image which is projected onto said screen by said projection device;

said distortion correction calculator calculates a distortion correction coefficient for said projected image inputted to said projection device so that the outer profile of said projected image is aligned with the boundary line between said screen and the background scene, based on the projection surface detected by said projection surface detector; and

said image controller corrects said projected image based on said distortion correction coefficient.

6. A projector according to claim 1, further comprising:

an image controller for controlling a projected image;

a projection surface detector for detecting distances up to said object points from the three-dimensional positions of a plurality of said predetermined object points which are detected by said three-dimensional position detector and arranging the detected distances two-dimensionally; and

a person detector/mask position calculator for detecting an obstacle including a person interposed between the projected image which is projected onto said projection object and said projection device and generating information to mask a projected image which is projected onto the obstacle;

wherein said object points are indicated two-dimensionally on the projected image which is projected onto said projection object;

said person detector/mask position calculator compares distances up to said object points with said projection surface detector, extracts a group of a plurality of said object points which are disposed at shorter distances and arranged two-dimensionally, defines the extracted group as the obstacle including a person, and acquires two-dimensional positions of said group; and

said image controller converts an image of a portion of said projected image which corresponds to the two-dimensional positions of said group into a predetermined color, and projects the image in the predetermined color from said projection device.

7. A projector according to claim 1, further comprising:

an image controller for controlling a projected image;

an image information generator for generating image information;

a projection surface detector for detecting distances up to said object points from the three-dimensional positions of a plurality of said predetermined object points which are detected by said three-dimensional position detector and arranging the detected distances two-dimensionally; and

a pointed position detector for detecting an obstacle having a predetermined shape which is interposed between a predetermined area of the projected image which is projected onto said projection object, as a pointing command;

wherein said object points are indicated two-dimensionally on the projected image which is projected onto said projection object;

said pointed position detector compares distances up to said object points with said projection surface detector, extracts a group of a plurality of said object points which are disposed on a surface of the projection object and disposed in a predetermined shape at shorter distances, defines the extracted group as the pointing command, acquires two-dimensional positions of said group, and outputs the acquired two-dimensional positions of said group to said image information generator; and

said image information generator reads contents of the pointing command from the two-dimensional positions of said group input thereto, performs a process corresponding to the pointing command, adds corresponding information to said image information, and outputs the image information with the added information to said image controller.

8. A projector according to claim 1, wherein said three-dimensional position detector detects the three-dimensional position of the predetermined object point, according to triangulation from the relationship between the positions on element surfaces of said cameras, of the identical object points in the respective images captured by said cameras and the positions of lenses of said cameras.

9. A projector according to claim 1, wherein said imager has at least two cameras.