Pulsed Laser-Based Firearm Training System, and Method for Facilitating Firearm Training Using Detection of Laser Pulse Impingement of Projected Target Images
First Claim
1. A method for automatic calibration of a laser-based firearm training system having a projector for projecting images onto a surface and a camera for reading images projected onto the surface, comprising:
- projecting a first image comprised of horizontal and vertical lines upon the surface;
reading the first image;
adjusting an exposure setting of the camera based on the first image so as to ensure pixel values below saturation;
projecting a second image comprising a black color upon the surface;
reading the second image;
calculating a background light level value for each pixel in the second image;
projecting a third image comprising a pattern of horizontal lines upon the surface;
reading the third image;
calculating a horizontal calibration value for each pixel in the third image, wherein the resulting horizontal calibration value for each pixel is reduced by the corresponding background light level value;
projecting a fourth image comprising a pattern of vertical lines upon the surface;
reading the fourth image;
calculating a vertical calibration value for each pixel in the fourth image, wherein the resulting vertical calibration value for each pixel is reduced by the corresponding background light level value;
calculating a centroid line for each vertical and horizontal line and calculating a second order line least squares fit for each centroid line, thereby generating three coefficients that describe each vertical and horizontal line; and
generating a data map for mapping a pixel from an image read from the surface to a pixel in an image projected into the surface, wherein the data map is based on the three coefficients that describe each vertical and horizontal line.
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Abstract
The invention provides a method for automatic calibration and subsequent correlation of the position of a pulsed laser on a projected image in a system having a projector for projecting images onto a surface and a camera for sensing laser pulses on the surface. The automatic calibration method sets the camera exposure, allowing the system to operate in normal room-lighting conditions, and correlates camera pixel positions to projected image pixel positions by use of projected calibration images formed by sets of horizontal and vertical lines, with automatic calibration completing in less than 5 seconds. After calibration, the system determines two-dimensional camera pixel centroids of laser beam pulses on the projection surface to sub-pixel accuracy, and the calibration data is used to correlate the camera pixel centroids to the exact positions of the laser pulses on the projected image.
13 Citations
23 Claims
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1. A method for automatic calibration of a laser-based firearm training system having a projector for projecting images onto a surface and a camera for reading images projected onto the surface, comprising:
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projecting a first image comprised of horizontal and vertical lines upon the surface; reading the first image; adjusting an exposure setting of the camera based on the first image so as to ensure pixel values below saturation; projecting a second image comprising a black color upon the surface; reading the second image; calculating a background light level value for each pixel in the second image; projecting a third image comprising a pattern of horizontal lines upon the surface; reading the third image; calculating a horizontal calibration value for each pixel in the third image, wherein the resulting horizontal calibration value for each pixel is reduced by the corresponding background light level value; projecting a fourth image comprising a pattern of vertical lines upon the surface; reading the fourth image; calculating a vertical calibration value for each pixel in the fourth image, wherein the resulting vertical calibration value for each pixel is reduced by the corresponding background light level value; calculating a centroid line for each vertical and horizontal line and calculating a second order line least squares fit for each centroid line, thereby generating three coefficients that describe each vertical and horizontal line; and generating a data map for mapping a pixel from an image read from the surface to a pixel in an image projected into the surface, wherein the data map is based on the three coefficients that describe each vertical and horizontal line. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for automatic detection of a laser pulse in a laser-based firearm training system having a projector for projecting images onto a surface and a camera for reading images projected onto the surface, comprising:
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reading a first projected image into a first data structure; searching for a laser pulse in the image by searching for pixels in the first data structure with a pixel value exceeding a predefined threshold; selecting a set of pixels around a pixel having a pixel value exceeding a predefined threshold; calculating a centroid of the laser pulse in the first data structure by performing a two dimensional centroid calculation upon the set of pixels; and calculating a pixel location of the laser pulse in the first image based on the centroid. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A firearm laser training system operable to detect the location of a projected laser beam pulse upon a projected target image is provided, said system comprising:
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a projection means operable to project a target image upon a surface; a video camera means operable to scan said target image to produce scanned images of said target image, including impact locations of said laser beam pulse on said target image; and a processing means operable to receive from said video camera means information associated with said impact locations detected by said video camera means, said processing means comprising; an automatic calibration module operable to correlate camera pixels to target pixels of the projected target image; a detection module operable to determine a camera pixel position of the laser beam pulse; and a shot correlation module operable to correlate the camera pixel position of the laser beam pulse to the projected target image, so as to determine the accuracy of the shot. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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Specification