Hybrid system for multi-projector geometry calibration
A method of calibrating a multi-projector image display system is provided. According to the method, non-parametric calibration data for the display system is recovered and used to generate a non-parametric model of the display system. Local parametric models relating to the display surface of the projection screen are generated and are compared with data points defined by the non-parametric calibration data to identify one or more local errors in the non-parametric calibration data. The local errors in the non-parametric calibration data are converted to data points defined at least in part by the local parametric models and the projectors are operated to project an image on the image projection screen by utilizing a hybrid calibration model comprising data points taken from the non-parametric model and data points taken from one or more local parametric models. Additional embodiments are disclosed and claimed.
1. A method of calibrating an image display system comprising a plurality of projectors oriented in the direction of an image projection screen and at least one calibration camera, wherein at least the following conditions apply to the method:
the calibration camera captures k distinct images of the image projection screen;
all projectors contributing to each captured image render a set of fiducials captured by the calibration camera;
a set of three-dimensional points corresponding to camera image points are computed as respective intersections of back-projected rays defined by the points and a canonical surface approximating the projection screen;
the points are matched with projected fiducials to generate a set of corresponding match points;
the set of three-dimensional points observed in different camera views are represented as a set of 3D surface points with a known neighborhood function;
the 3D points are modeled as a constraint system such that the error distance between two points seen in two different camera views are computed as the geodesic distance between the first point, as seen in the second view, and the second point, as seen in that same view; and
points that correspond to the same projector location but have different locations on the 3D surface are adjusted according to an error metric that minimizes the total error represented in the constraint system.
2. A method as claimed in claim 1 wherein the projectors are operated to project an image on the image projection screen by utilizing a hybrid calibration model comprising data points taken from a non-parametric model of the display system derived from the constraint system and data points taken from one or more local parametric models of the display system.