Method and apparatus for calibrating a computer-generated projected image
First Claim
1. A method for correlating the projection coordinates Q(xQ,yQ) of image elements projected onto a surface to the display coordinates P(xP,yP) of the corresponding image elements as displayed on a computer screen, said method comprising the steps of:
- generating a set of n calibration spots disposed in a nonlinear pattern within the displayed image, where n≧
4, the predetermined coordinates of said calibration spots denoted by Pi(xP,yP), where 1≦
i≦
n, each said calibration spot having a brightness greater than a predetermined threshold level;
projecting the displayed image and said calibration spots onto the projection surface so as to form a calibration image thereon, said calibration image comprising n bright clusters corresponding to said n calibration spots;
determining the projection coordinate of the mean position Qi(xQ,yQ) of each of said n bright clusters; and
, deriving transformation coefficient matrices A and B by solving the set of vector equations given by;
2 Assignments
0 Petitions
Accused Products
Abstract
An apparatus and method for calibrating a computer-generated projected image to the displayed image viewed on the computer screen. Four or more calibration spots, at least three of which are collinear, arrayed in a predetermined pattern in both the displayed and the projected images, are optically imaged and electronically discriminated in the projected image, their coordinates ascertained and related to the predetermined pattern so as to derive transformation coefficients used in the process of converting a location on the projected image to the corresponding location in the displayed image.
137 Citations
29 Claims
-
1. A method for correlating the projection coordinates Q(xQ,yQ) of image elements projected onto a surface to the display coordinates P(xP,yP) of the corresponding image elements as displayed on a computer screen, said method comprising the steps of:
-
generating a set of n calibration spots disposed in a nonlinear pattern within the displayed image, where n≧
4, the predetermined coordinates of said calibration spots denoted by Pi(xP,yP), where 1≦
i≦
n, each said calibration spot having a brightness greater than a predetermined threshold level;
projecting the displayed image and said calibration spots onto the projection surface so as to form a calibration image thereon, said calibration image comprising n bright clusters corresponding to said n calibration spots;
determining the projection coordinate of the mean position Qi(xQ,yQ) of each of said n bright clusters; and
,deriving transformation coefficient matrices A and B by solving the set of vector equations given by;
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method for correlating the projection coordinates Q(xQ,yQ) of image elements projected onto a surface to the display coordinates P(xP,yP) of the corresponding image elements as displayed on a computer screen, said method comprising the steps of:
-
generating a set of n calibration spots disposed in a nonlinear pattern within the displayed image, where n≧
4, the predetermined coordinates of said calibration spots denoted by Pi(xP,yP), where 1≦
i≦
n, each said calibration spot having a predetermined height and a predetermined width;
projecting the displayed image and said calibration spots onto the projection surface so as to form a calibration image thereon;
imaging and filtering said calibration image so as to sense only filtered image elements having a brightness greater than a predetermined threshold level;
grouping adjacent said filtered image elements into a plurality of bright clusters, each said bright cluster having a corresponding height and width;
spatially filtering said plurality of bright clusters so as to sense only bright clusters having a height at least as great as a predetermined value (h1) and having a width at least as great as a predetermined value (w1);
counting said spatially filtered bright clusters, wherein if more than n said spatially filtered bright clusters are counted, selecting a threshold level higher than said predetermined threshold level and repeating said steps of filtering said calibration image, grouping said filtered image elements, spatially filtering said bright clusters, and counting said spatially filtered bright clusters, and if fewer than n said filtered bright clusters are counted, selecting a threshold level lower than said predetermined threshold level and repeating said steps of filtering said calibration image, grouping said filtered image elements, spatially filtering said bright clusters, and counting said spatially filtered bright clusters;
determining the projection coordinate of the mean position Qi(xQ,yQ) of each of said n spatially filtered bright clusters; and
,deriving transformation coefficient matrices A and B by solving the set of vector equations given by;
- View Dependent Claims (11, 12, 13, 14, 15)
-
-
16. A calibration apparatus, suitable for correlating the projection coordinates Q(xQ,yQ) of an image projected onto a surface to the display coordinates P(xP,yP) of the corresponding image and included calibration spots as displayed on a computer screen, the image comprising n calibration spots disposed in a nonlinear pattern within the projected image, where n≧
- 4, said calibration apparatus comprising;
means for imaging and filtering said calibration image so as to sense only the n projected calibration spots;
means for determining the projection coordinates of the mean position Qi(xQ,yQ) for each of said calibration spots, where 1≦
i≦
n;
means for deriving conversion matrices A and B by solving the set of vector equations given by;
- View Dependent Claims (17, 18, 19, 20)
- 4, said calibration apparatus comprising;
-
21. A medium readable by a machine embodying a program of instructions executable by said machine to perform a method for correlating the projection coordinates Q(xQ,yQ) of image elements projected onto a surface to the display coordinates P(xP,yP) of the corresponding image elements as displayed on a computer screen, said method comprising the steps of:
-
generating a set of n calibration spots disposed in a nonlinear pattern within the displayed image, where n≧
4, the predetermined coordinates of said calibration spots denoted by Pi(xP,yP), where 1≦
i≦
n, each said calibration spot having a brightness greater than a predetermined threshold level;
projecting the displayed image and said calibration spots onto the projection surface so as to form a calibration image thereon, said calibration image comprising n bright clusters corresponding to said n calibration spots;
determining the projection coordinate of the mean position Qi(xQ,yQ) of each of said n bright clusters; and
,deriving transformation coefficient matrices A and B by solving the set of vector equations given by;
- View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
-
Specification