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

• US 20050213821A1
• Filed: 03/18/2005
• Published: 09/29/2005
• Est. Priority Date: 03/29/2004
• Status: Active Grant

• Current Assignee: Columbia Peak Ventures, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Matsuda, Hideki
• Granted Patent: US 7,517,089 B2
• Time in Patent Office: Days
• US Class Current: 382/199
• 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

A projector is configured of a difference image generation section that generates a difference image between an all-white first calibration image and a second calibration image which includes an image having features at the center and periphery thereof, a center reference position detection section that detects a reference position of a center block area in the difference image, a peripheral reference position detection section that detects a reference position of a peripheral block area, and a projection area information generation section that generates projection area information indicating a position of a projection area, based on those reference positions.

Claims

1. An image processing system comprising:

image projection means for projecting a first calibration image and a second calibration image at different timings;

sensing means for sensing the projected first and second calibration images and generating first and second sensing information; and

projection area detection means for generating projection area information relating to a position of a projection area in a sensing area of the sensing means, based on the first and second sensing information,

wherein a difference image between the first calibration image and the second calibration image is configured of a center block area positioned around the center of the difference image, a peripheral block area positioned on a periphery of the center block area, and a background area which is an area other than the center block area and the peripheral block area,

wherein each pixel in the center block area and the peripheral block area has a different index value from each pixel in the background area, and

wherein the projection area detection means comprises;

difference image generation means for generating the difference image, based on the first and second sensing information;

center reference position detection means for detecting a plurality of center reference positions of the center block area in the sensing area, based on the difference image;

peripheral reference position detection means for detecting a plurality of peripheral reference positions of the peripheral block area in the sensing area, based on the center reference positions; and

projection area information generation means for generating the projection area information, based on the center reference positions and the peripheral reference positions.

2. The image processing system as defined in claim 1,

wherein the projection area information generation means generates the projection area information by setting a plurality of approximated straight lines or approximated curves based on the center reference positions and the peripheral reference positions and determining the shape or arrangement of the center block area and the peripheral block area.

3. The image processing system as defined in claim 2,

wherein the projection area and the center block area are rectangular areas, and

wherein the projection area information generation means determines positions of four comers of the center block area by deriving intersections of the plurality of approximated straight lines or intersections of the plurality of approximated curves, and generates the projection area information indicating positions of four comers of the projection area, based on the positions of the four comers of the center block area.

4. The image processing system as defined in claim 1, further comprising:

projection-target area boundary point detection means for detecting a plurality of boundary points of projection-target area corresponding to a projection target in the sensing area, based on the first sensing information and the center reference positions;

wherein the peripheral reference position detection means detects the peripheral reference positions, based on the boundary points.

6. A projector having the image processing system as defined in claim 1.

5. An image processing system comprising:

an image projection section which projects a first calibration image and a second calibration image at different timings;

a sensing section which senses the projected first and second calibration images and generates first and second sensing information; and

a projection area detection section which generates projection area information relating to a position of a projection area in a sensing area of the sensing section, based on the first and second sensing information,

wherein a difference image between the first calibration image and the second calibration image is configured of a center block area positioned around the center of the difference image, a peripheral block area positioned on a periphery of the center block area, and a background area which is an area other than the center block area and the peripheral block area,

wherein each pixel in the center block area and the peripheral block area has a different index value from each pixel in the background area, and

wherein the projection area detection section comprises;

a difference image generation section which generates the difference image, based on the first and second sensing information;

a center reference position detection section which detects a plurality of center reference positions of the center block area in the sensing area of the sensing section, based on the difference image;

a peripheral reference position detection section which detects a plurality of peripheral reference positions of the peripheral block area in the sensing area, based on the center reference positions; and

a projection area information generation section which generates the projection area information, based on the center reference positions and the peripheral reference positions.

7. A program for causing a computer to function as:

image projection means for projecting a first calibration image and a second calibration image at different timings;

sensing means for sensing the projected first and second calibration images and generating first and second sensing information; and

projection area detection means for generating projection area information relating to a position of a projection area in a sensing area of the sensing means, based on the first and second sensing information,

wherein a difference image between the first calibration image and the second calibration image is configured of a center block area positioned around the center of the difference image, a peripheral block area positioned on a periphery of the center block area, and a background area which is an area other than the center block area and the peripheral block area,

wherein each pixel in the center block area and the peripheral block area has a different index value from each pixel in the background area, and

wherein the projection area detection means comprises;

difference image generation means for generating the difference image, based on the first and second sensing information;

center reference position detection means for detecting a plurality of center reference positions of the center block area in the sensing area, based on the difference image;

peripheral reference position detection means for detecting a plurality of peripheral reference positions of the peripheral block area in the sensing area, based on the center reference positions; and

projection area information generation means for generating the projection area information, based on the center reference positions and the peripheral reference positions.

8. An information storage medium which stores the program as defined in claim 7.

9. An image processing method for performing image processing based on a difference image which is a difference image between a first calibration image and a second calibration image, the difference image being configured of a center block area positioned around the center of the difference image, a peripheral block area positioned on a periphery of the center block area, and a background area which is an area other than the center block area and the peripheral block area, and each pixel in the center block area and the peripheral block area having a different index value from each pixel in the background area, the image processing method comprising:

projecting the first calibration image;

sensing the projected first calibration image by using a sensing section, to generate first sensing information;

projecting the second calibration image;

sensing the projected second calibration image by using the sensing section, to generate second sensing information;

generating the difference image, based on the first and second sensing information;

detecting a plurality of center reference positions of the center block area in a sensing area of the sensing section, based on the difference image;

detecting a plurality of peripheral reference positions of the peripheral block area in the sensing area, based on the center reference positions; and

generating projection area information relating to a position of a projection area in the sensing area, based on the center reference positions and the peripheral reference positions.

10. The image processing method as defined in claim 9, comprising:

generating the projection area information by setting a plurality of approximated straight lines or approximated curves based on the center reference positions and the peripheral reference positions and determining the shape or arrangement of the center block area and the peripheral block area.

11. The image processing method as defined in claim 10,

wherein the projection area and the center block area are rectangular areas,

the image processing method comprising:

determining positions of four comers of the center block area by deriving intersections of the plurality of approximated straight lines or intersections of the plurality of approximated curves, and generating the projection area information indicating positions of four comers of the projection area, based on the positions of the four corners of the center block area.

12. The image processing method as defined in claim 9, comprising:

detecting a plurality of boundary points of projection-target area corresponding to a projection target in the sensing area, based on the first sensing information and the center reference positions; and

detecting the peripheral reference positions based on the boundary points.

13. An image processing system comprising:

image projection means for projecting a first calibration image towards a projection target;

sensing means for sensing the projected first calibration image at a low resolution which is less than or equal to a predetermined resolution, to generate first sensing information, and also for sensing the first calibration image at a high resolution which is greater than or equal to the low resolution, to generate third sensing information; and

projection-target area detection means for generating projection-target area information relating to a position of a projection-target area corresponding to the projection target in a sensing area of the sensing means, based on the first and third sensing information,

wherein the projection-target area detection means comprises;

edge detection means for performing edge detection to generate first edge detection information, based on the first sensing information, and also performing edge detection to generate third edge detection information, based on the third sensing information; and

projection-target area information generation means for generating provisional detection information by provisionally detecting the projection-target area based on the first edge detection information, and also generating the projection-target area information based on the third edge detection information,

wherein the edge detection means generates the third edge detection information by performing edge detection on a pixel group around a boundary line of the provisionally detected projection-target area, based on the provisional detection information.

14. The image processing system as defined in claim 13,

wherein the edge detection means detects edges at a plurality of locations within a first sensed image based on the first sensing information, to generate the first edge detection information, and

wherein the projection-target area information generation means generates the provisional detection information by setting a linear approximated straight line or linear approximated curve, based on positional information of the plurality of locations which is based on the first edge detection information.

15. The image processing system as defined in claim 14,

wherein the projection-target area detection means comprises detection point evaluation means for evaluating a plurality of edge detection points, and

wherein the detection point evaluation means determines whether or not each of the plurality of edge detection points is distanced from the linear approximated straight line or the linear approximated curve by at least a predetermined value, and controls the projection-target area information generation means in such a manner that a detection point which is distanced by at least the predetermined value is excluded and the linear approximated straight line or the linear approximated curve is reset.

16. The image processing system as defined in claim 13, further comprising:

difference image generation means for generating a difference image; and

center reference position detection means for detecting a plurality of center reference positions of a predetermined center block area in the sensing area, based on the difference image,

wherein the projection-target area detection means comprises search area determination means for setting an edge detection area by the edge detection means,

wherein the image projection means projects a second calibration image,

wherein the sensing means senses the projected second calibration image and generates second sensing information,

wherein the difference image generation means generates the difference image, based on the first and second sensing information,

wherein the search area determination means sets the edge detection area outside the center block area,

wherein the first calibration image is a monochrome calibration image, and

wherein the second calibration image comprises the center block area which is smaller than the second calibration image and which is positioned around the center of the second calibration image.

17. The image processing system as defined in claim 16,

wherein the second calibration image is configured of the center block area, a peripheral block area positioned on a periphery of the center block area, and a background area that is an area other than the center block area and the peripheral block area,

wherein each pixel in the center block area and the peripheral block area has a different index value from each pixel in the background area,

the image processing system comprising:

peripheral reference position detection means for detecting a plurality of peripheral reference positions of the peripheral block area in the sensing area, based on the center reference positions; and

projection area information generation means for generating projection area information relating to a position of a projection area in the sensing area, based on the center reference positions and the peripheral reference positions.

18. The image processing system as defined in claim 17,

wherein the projection area information generation means generates the projection area information by setting a plurality of approximated straight lines or approximated curves based on the center reference positions and the peripheral reference positions and determining the shape or arrangement of the center block area and the peripheral block area.

19. The image processing system as defined in claim 18,

wherein the projection area and the center block area are rectangular areas, and

wherein the projection area information generation means determines positions of four corners of the center block area by deriving intersections of the plurality of approximated straight lines or intersections of the plurality of approximated curves, and generates the projection area information indicating positions of four comers of the projection area, based on the positions of the four comers of the center block area.

20. The image processing system as defined in claim 17, further comprising:

projection-target area boundary point detection means for detecting a plurality of boundary points of the projection-target area, based on the first sensing information and the center reference positions,

wherein the peripheral reference position detection means detects the peripheral reference positions, based on the boundary points.

21. The image processing system as defined in claim 17, further comprising:

image distortion correction means for determining whether there is distortion in an image projected by the image projection means, based on the projection-target area information and the projection area information, and correcting an image signal to correct the distortion,

wherein the image projection means projects an image based on the image signal which has been corrected by the image distortion correction means.

23. A projector having the image processing system as defined in claim 13.

22. An image processing system comprising:

an image projection section which projects a first calibration image towards a projection target;

a sensing section which senses the projected first calibration image at a low resolution which is less than or equal to a predetermined resolution, to generate first sensing information, and also senses the first calibration image at a high resolution which is greater than or equal to the low resolution, to generate third sensing information; and

a projection-target area detection section which generates projection-target area information relating to a position of a projection-target area corresponding to the projection target in a sensing area of the sensing section, based on the first and third sensing information,

wherein the projection-target area detection section comprises;

an edge detection section which performs edge detection to generate first edge detection information, based on the first sensing information, and also performs edge detection to generate third edge detection information, based on the third sensing information; and

a projection-target area information generation section which generates provisional detection information by provisionally detecting the projection-target area based on the first edge detection information, and also generates the projection-target area information based on the third edge detection information,

wherein the edge detection section generates the third edge detection information by performing edge detection on a pixel group around a boundary line of the provisionally detected projection-target area, based on the provisional detection information.

24. A program for causing a computer to function as:

image projection means for projecting a first calibration image towards a projection target;

sensing means for sensing the projected first calibration image at a low resolution which is less than or equal to a predetermined resolution, to generate first sensing information, and also for sensing the first calibration image at a high resolution which is greater than or equal to the low resolution, to generate third sensing information; and

projection-target area detection means for generating projection-target area information relating to a position of a projection-target area corresponding to the projection target in a sensing area of the sensing means, based on the first and third sensing information,

wherein the projection-target area detection means comprises;

edge detection means for performing edge detection to generate first edge detection information, based on the first sensing information, and also performing edge detection to generate third edge detection information, based on the third sensing information; and

projection-target area information generation means for generating provisional detection information by provisionally detecting the projection-target area based on the first edge detection information, and also generating the projection-target area information based on the third edge detection information,

wherein the edge detection means generates the third edge detection information by performing edge detection on a pixel group around a boundary line of the provisionally detected projection-target area, based on the provisional detection information.

25. An information storage medium which stores the program as defined in claim 24.

26. An image processing method comprising:

projecting a first calibration image towards a projection target;

sensing the projected first calibration image at a low resolution which is less than or equal to a predetermined resolution by using a sensing section, to generate first sensing information;

sensing the first calibration image at a high resolution which is greater than or equal to the low resolution by using the sensing section, to generate third sensing information;

performing edge detection to generate first edge detection information, based on the first sensing information;

generating provisional detection information by provisionally detecting a projection-target area corresponding to the projection target in a sensing area of the sensing section, based on the first edge detection information;

generating third edge detection information by performing edge detection on a pixel group around a boundary line of the provisionally detected projection-target area, based on the provisional detection information; and

detecting the projection-target area to generate projection-target area information relating to a position of the projection-target area, based on the third edge detection information.

27. The image processing method as defined in claim 26, comprising:

detecting edges at a plurality of locations within a first sensed image based on the first sensing information, to generate the first edge detection information; and

generating the provisional detection information by setting a linear approximated straight line or linear approximated curve, based on positional information of the plurality of locations which is based on the first edge detection information.

28. The image processing method as defined in claim 27, comprising:

determining whether or not each of a plurality of edge detection points is distanced from the linear approximated straight line or the linear approximated curve by at least a predetermined value; and

resetting the linear approximated straight line or the linear approximated curve in such a manner that a detection point which is distanced by at least the predetermined value is excluded.

29. The image processing method as defined in claim 26, further comprising:

projecting a second calibration image;

sensing the projected second calibration image by using the sensing section, to generate second sensing information;

generating a difference image, based on the first and second sensing information;

detecting a plurality of center reference positions of a predetermined center block area in the sensing area, based on the difference image; and

setting an edge detection area outside the center block area,

wherein the first calibration image is a monochrome calibration image, and

wherein the second calibration image comprises the center block area which is smaller than the second calibration image and which is positioned around the center of the second calibration image.

30. The image processing method as defined in claim 29,

wherein the second calibration image is configured of the center block area, a peripheral block area positioned on a periphery of the center block area, and a background area that is an area other than the center block area and the peripheral block area,

wherein each pixel in the center block area and the peripheral block area has a different index value from each pixel in the background area,

the image processing method further comprising:

detecting a plurality of peripheral reference positions of the peripheral block area in the sensing area, based on the center reference positions; and

generating projection area information relating to a position of a projection area in the sensing area, based on the center reference positions and the peripheral reference positions.

31. The image processing method as defined in claim 30, comprising:

generating the projection area information by setting a plurality of approximated straight lines or approximated curves based on the center reference positions and the peripheral reference positions and determining the shape or arrangement of the center block area and the peripheral block area.

32. The image processing method as defined in claim 31,

wherein the projection area and the center block area are rectangular areas,

the image processing method comprising:

determining positions of four comers of the center block area by deriving intersections of the plurality of approximated straight lines or intersections of the plurality of approximated curves, and generating the projection area information indicating positions of four comers of the projection area, based on the positions of the four corners of the center block area.

33. The image processing method as defined in claim 30, comprising:

detecting a plurality of boundary points of the projection-target area, based on the first sensing information and the center reference positions; and

detecting the peripheral reference positions, based on the boundary points.

34. The image processing method as defined in claim 30, comprising:

determining whether there is distortion in an image to be projected, based on the projection-target area information and the projection area information, and correcting an image signal to correct the distortion.