Trajectory detection and analysis in sporting events
View Patent ↗It is provided a method for conveying data on a flying object in a scene. The method including capturing video frames of the scene by video cameras to get video frames which include image of the object, identifying the object in captured video frames to get associated object parameters, calculating motion variables, solving motion equations for anticipated object trajectory taking into account certain effects, and conveying data to displaying devices. The certain effects are an effect of object collision with a ground surface, air friction, wind effect, and interaction of a spinning object with air. The method may be applied to a ball in a sporting playing field. The cameras may have variable operating parameters desirable for the calculating the motion variables, which may be determined by camera calibration using captured artifacts of the scene. Shadow of the object may be captured as well and be used to provide data absent due to occluding a of the object from a video camera. Also, the captured frames of a ball may be used to calculate parameters relating to a bat which hits the ball.
1. A method for conveying data on a flying object in a playing field illuminated by at least one light source providing a shadow of the flying object, two or more video cameras viewing the playing field, at least one camera having at least one variable operating parameter, the method comprising:
(a) capturing a plurality of video frames of the playing field by the two or more video cameras to get a plurality of video frames including images of the object and at least one video frame including image of the shadow of the flying object;
(b) calibrating a value of the at least one variable operating parameter of the at least one camera using at least one location of at least one pre-existing artifact of the playing field, including:
(i) said at least one location being taken by a measuring device,
(ii) said value being associated with capturing video frames of said plurality of video frames, and
(iii) said measuring device being one of a laser rangefinder and a theodolite;
(c) identifying said object in captured video frames to get object parameters associated with said captured video frames, said object parameters being determined using said at least one variable operating parameter of said at least one video camera;
(d) identifying said object shadow in at least one captured video frame to get parameters of the object shadow associated with said at least one captured video frame;
(e) calculating one or more motion variables of said object using said object parameters, using said parameters of the object shadow, and using parameters associated with the light source;
(f) based on the calculated motion variables, solving motion equations for determining an anticipated object trajectory; and
(g) conveying data related to the anticipated object trajectory as calculated using said parameters of the object shadow to one or more devices.
2. The method of claim 1 , wherein the method additionally comprises: complementing data absence caused by occluding of said object from a video camera of said two or more video cameras.
3. The method of claim 1 , wherein said flying object includes a ball.