Method for estimating a 3D trajectory of a projectile from 2D camera images
First Claim
1. A method for estimating a 3D trajectory of a projectile from 2D camera images, comprising:
- obtaining a sequence of 2D camera images from a camera, wherein one or more 2D camera images of said sequence of 2D camera images comprise an image of a projectile;
identifying a pixel location of said projectile in each 2D camera image of said one or more 2D camera images;
calculating a camera projection transform that maps points in a world reference frame into pixel positions in said sequence of 2D camera images;
calculating a model that maps projectile initial conditions into a modeled pixel position for said projectile in each 2D camera image of said one or more 2D camera images, wherein said projectile initial conditions comprisean initial position vector in said world reference frame for said projectile; and
,an initial velocity vector in said world reference frame for said projectile; and
,calculating estimated projectile initial conditions as projectile initial conditions that minimize differences between said modeled pixel position for said projectile and said pixel location of said projectile across said one or more 2D camera images.
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Abstract
A method that estimates the 3D trajectory of a projectile, such as a golf ball or baseball, by analyzing a sequence of images from a single-lens, 2D camera. Image analysis may be used to locate the projectile in the camera images, using motion detection and filters for the projectile'"'"'s expected size and shape. A physics model may be used to calculate the projectile'"'"'s trajectory as a function of its initial position and velocity (for example, just after impact with a golf club or bat). A camera projection transform may map this trajectory into predicted pixel locations, which may be compared to the observed projectile locations in the camera images. The projectile'"'"'s trajectory may be estimated by finding initial conditions that minimize differences between observed and predicted pixel locations, using a nonlinear least squares solver for example. The method may be extended to multiple cameras.
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Citations
20 Claims
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1. A method for estimating a 3D trajectory of a projectile from 2D camera images, comprising:
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obtaining a sequence of 2D camera images from a camera, wherein one or more 2D camera images of said sequence of 2D camera images comprise an image of a projectile; identifying a pixel location of said projectile in each 2D camera image of said one or more 2D camera images; calculating a camera projection transform that maps points in a world reference frame into pixel positions in said sequence of 2D camera images; calculating a model that maps projectile initial conditions into a modeled pixel position for said projectile in each 2D camera image of said one or more 2D camera images, wherein said projectile initial conditions comprise an initial position vector in said world reference frame for said projectile; and
,an initial velocity vector in said world reference frame for said projectile; and
,calculating estimated projectile initial conditions as projectile initial conditions that minimize differences between said modeled pixel position for said projectile and said pixel location of said projectile across said one or more 2D camera images. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification