Systems and methods for using visual hulls to determine the number of people in a crowd
First Claim
1. A method for determining the number of a plurality of objects in a working volume, the method comprising:
- determining a first planar projection of a first visual hull of the plurality of objects, the planar projection comprising a first set of one or more shapes; and
determining a first set of one or more lower bounds, a lower bound being associated with a shape in the first set of one or more shapes, a lower bound being a lowest number of objects that can be contained in the associated shape.
2 Assignments
0 Petitions
Accused Products
Abstract
Systems, apparatuses, and methods are presented that determine the number of people in a crowd using visual hull information. In one embodiment, an image sensor generates a conventional image of a crowd. A silhouette image is then determined based on the conventional image. The intersection of the silhouette image cone and a working volume is determined. The projection of the intersection onto a plane is determined. Planar projections from several image sensors are aggregated by intersecting them, forming a subdivision pattern. Polygons that are actually empty are identified and removed. Upper and lower bounds of the number of people in each polygon are determined and stored in a tree data structure. This tree is updated as time passes and new information is received from image sensors. The number of people in the crowd is equal to the lower bound of the root node of the tree.
-
Citations
42 Claims
-
1. A method for determining the number of a plurality of objects in a working volume, the method comprising:
-
determining a first planar projection of a first visual hull of the plurality of objects, the planar projection comprising a first set of one or more shapes; and determining a first set of one or more lower bounds, a lower bound being associated with a shape in the first set of one or more shapes, a lower bound being a lowest number of objects that can be contained in the associated shape. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
-
-
23. A system for determining the number of a plurality of objects in a working volume, the system comprising:
-
means for determining a first planar projection of a first visual hull of the plurality of objects, the planar projection comprising a first set of one or more shapes; and means for determining a first set of one or more lower bounds, a lower bound being associated with a shape in the first set of one or more shapes, a lower bound being a lowest number of objects that can be contained in the associated shape. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
-
Specification