Mobile entity tracking device and method for tracking mobile entity

A moving body tracking device which tracks a moving body for a ball game, the moving body tracking device comprising:

• a video receiver which receives moving image frames of a ball game captured by each of a plurality of cameras at different positions;
• a moving body selector which
• displays a moving image frame captured by one of the cameras, and
• receives, from a user, a designation of a position of a moving body selected as a tracking target in the moving image frame captured by the one of the cameras;
• a moving body candidate extractor which
• extracts a moving body candidate which is present in a region of a three-dimensional space, the region of the three-dimensional space being formed of a search range that changes according to the designated position in the moving image frame captured by the one of the cameras, and
• extracts an image of the moving body candidate from a portion of a moving image frame captured by another camera, the portion corresponding to the region of the three-dimensional space;
• and
• a moving body tracker which tracks the moving body as the tracking target, wherein
• the moving body selector displays the moving body candidate image and receives the selection of the tracking target,
• when the moving body selector receives the selection of the tracking target from the user, the moving body tracker corrects the moving body as the tracking target to the moving body selected by the user, and
• the search range includes a point on a search axis in the three-dimensional space, the search axis being calculated based on the designated position.

A method for tracking a moving body which tracks a moving body for a ball game, the method comprising:

• receiving moving image frames of a ball game captured by each of a plurality of cameras at different positions;
• displaying a moving image frame captured by one of the cameras;
• receiving, from a user, a designation of a position of a moving body selected as a tracking target in the moving image frame captured by the one of the cameras;
• extracting a plurality of moving body candidates which is present in a region of a three-dimensional space, the region of the three-dimensional space being formed of a search range that changes according to the designated position in the moving image frame captured by the one of the cameras;
• extracting an image of each of the plurality of moving body candidates from a portion of a moving image frame captured by another camera, the portion corresponding to the region of the three-dimensional space;
• tracking the moving body as the tracking target;
• displaying the moving body candidate images in order of height of position of each of the plurality of moving body candidates in the three-dimensional space and receiving the selection of the tracking target;
• and
• when receiving the selection of the tracking target from the user, correcting the tracking target to the moving body selected by the user.

A moving body tracking method which tracks a moving body for a ball game, the moving body tracking method comprising:

• receiving moving image frames of a ball game captured by each of a plurality of cameras at different positions;
• displaying a moving image frame captured by one of the cameras;
• receiving, from a user, a designation of a position of a moving body selected as a tracking target in the moving image frame captured by the one of the cameras;
• extracting a moving body candidate which is present in a region of a three-dimensional space, the region of the three-dimensional space being formed of a search range that changes according to the designated position in the moving image frame captured by the one of the cameras;
• extracting an image of the moving body candidate from a portion of a moving image frame captured by another camera, the portion corresponding to the region of the three-dimensional space;
• tracking the moving body as the tracking target;
• displaying the moving body candidate image and receives the selection of the tracking target;
• and
• when the selection of the tracking target is received from the user, correcting the moving body as the tracking target to the moving body selected by the user,
• wherein the search range includes a point on a search axis in the three-dimensional space, the search axis being calculated based on the designated position.