Method and apparatus for calibrating geometrically an optical computer input system
First Claim
Patent Images
1. A coordinate correction apparatus comprising:
- image detection means for perceiving visually a displayed generally rectangularly shaped projected image having keystone distortion;
hand held auxiliary light means for successively illuminating the corners of the distorted image with spots of high intensity auxiliary control light for facilitating defining the geometric form of the keystone distortion in the projected image;
said image detection means responsive to said spots of high intensity light only during a calibration mode for generating a signal indicative of the location of the high intensity spots;
signal processing means responsive to said signal during said calibration mode for determining the geometric center of the geometric form of the keystone distortion defined by the intersection coordinate values of a pair of imaginary lines interconnecting the detected spots of high intensity light;
distortion orientation calculating means responsive to the determined geometric center for determining quadrant scaling factors to facilitate determining corrected coordinate values for detected spots of high intensity auxiliary control light during a normal mode of operation;
said signal processing means storing the scaling factors for use during said normal mode of operation to enable said signal processing means to convert subsequently a determined auxiliary light sensing coordinate value relative to another computer generated projected image having substantially the same keystone distortion as said first mentioned projected image;
said signal processing means using said stored scaling factors for converting the determined auxiliary light sensory coordinate values to absolute coordinate values, said absolute coordinate values being indicative of corresponding coordinate value information defining a fixed location within said another computer generated image.
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Abstract
A method and apparatus geometrically makes correction in an optical computer input system.
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Citations
18 Claims
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1. A coordinate correction apparatus comprising:
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image detection means for perceiving visually a displayed generally rectangularly shaped projected image having keystone distortion; hand held auxiliary light means for successively illuminating the corners of the distorted image with spots of high intensity auxiliary control light for facilitating defining the geometric form of the keystone distortion in the projected image; said image detection means responsive to said spots of high intensity light only during a calibration mode for generating a signal indicative of the location of the high intensity spots; signal processing means responsive to said signal during said calibration mode for determining the geometric center of the geometric form of the keystone distortion defined by the intersection coordinate values of a pair of imaginary lines interconnecting the detected spots of high intensity light; distortion orientation calculating means responsive to the determined geometric center for determining quadrant scaling factors to facilitate determining corrected coordinate values for detected spots of high intensity auxiliary control light during a normal mode of operation; said signal processing means storing the scaling factors for use during said normal mode of operation to enable said signal processing means to convert subsequently a determined auxiliary light sensing coordinate value relative to another computer generated projected image having substantially the same keystone distortion as said first mentioned projected image; said signal processing means using said stored scaling factors for converting the determined auxiliary light sensory coordinate values to absolute coordinate values, said absolute coordinate values being indicative of corresponding coordinate value information defining a fixed location within said another computer generated image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An apparatus for substantially eliminating errors in optical input information resulting from image distortion in a projected image, comprising
means for determining image detection coordinate values for any detected substantially flat generally rectangularly shaped projected image having possible edge distortion, said distortion being a distortion caused by a height differential between the position of the projected image on a viewing surface relative to the position of image projection means producing the projected image; -
said determined image detection coordinate values including four determined corner coordinate values; boundary distortion determination means for calculating whether or not any boundary between a pair of adjacent determined corner coordinate values is aligned rectilinearly relative to its associated determined corner coordinate values; distortion orientation means responsive to said boundary distortion determination means for determining the orientation of the distortion relative to an imaginary rectilinear line forming part of an imaginary rectilinearly shaped image; distortion correction means for calculating a set of corrected image detection coordinate values to eliminate errors in coordinate information resulting from edge distortion in the projected image; and absolute correction means responsive to said distortion correction means for converting said set of corrected image detection coordinate values to absolute coordinate values, said absolute coordinate values being indicative of corresponding coordinate value information generated by said image projection means.
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Specification