Method and computer system for detecting crowds in a location tracking system
First Claim
1. A method for detecting crowds in a location tracking system, the method comprising:
- defining, using at least one computer system, a grid in two dimensions in a geographic coordinate system, the grid having a predetermined spacing in each dimension between grid points of the grid;
receiving a geographic location from each of a plurality of objects, the geographic location including coordinates in each of the two dimensions in the geographic coordinate system;
comparing the geographic locations to the grid points and defining as an active grid point each of a plurality of the grid points that are positioned within the predetermined spacing to at least one of the objects in each of the two dimensions;
storing each of the active grid points using at least one memory device of the at least one computer system;
receiving an updated geographic location from a first one of the objects; and
checking, by at least one processing unit of the at least one computer system and using the updated geographic location and the geographic locations of other ones of the objects, for an existence of a crowd by determining whether there are four or more times a predetermined threshold number of the objects that are located within the predetermined spacing in each of the two dimensions to a first one of the active grid points that is within the predetermined spacing in each of the two dimensions to the updated geographic location.
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Accused Products
Abstract
A method and computer system for detecting crowds in a location tracking system utilizes a grid and the pigeonhole principle to minimize an amount of hardware, memory and/or processing capability required in the location tracking system. In particular, an amount of storage required to determine whether a location update has resulted in a crowd grows only linearly, rather than quadratically, with the number of objects being tracked because a number of active grid points will be, at most, four times the number of objects being tracked. By determining whether an individual active grid point is within a crowd area, the computational time required for detecting a crowd within this crowd area is independent from the total number of objects being tracked.
12 Citations
18 Claims
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1. A method for detecting crowds in a location tracking system, the method comprising:
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defining, using at least one computer system, a grid in two dimensions in a geographic coordinate system, the grid having a predetermined spacing in each dimension between grid points of the grid; receiving a geographic location from each of a plurality of objects, the geographic location including coordinates in each of the two dimensions in the geographic coordinate system; comparing the geographic locations to the grid points and defining as an active grid point each of a plurality of the grid points that are positioned within the predetermined spacing to at least one of the objects in each of the two dimensions; storing each of the active grid points using at least one memory device of the at least one computer system; receiving an updated geographic location from a first one of the objects; and checking, by at least one processing unit of the at least one computer system and using the updated geographic location and the geographic locations of other ones of the objects, for an existence of a crowd by determining whether there are four or more times a predetermined threshold number of the objects that are located within the predetermined spacing in each of the two dimensions to a first one of the active grid points that is within the predetermined spacing in each of the two dimensions to the updated geographic location. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A computer-readable, tangible, non-transitory medium having instructions therein which cause one or more processing units of at least one computer system to collectively perform the following steps:
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comparing geographic locations received from each of a plurality of objects to grid points of a grid defined in two dimensions in a geographic coordinate system, the grid having a predetermined spacing in each dimension between the grid points and the geographic locations including coordinates in each of the two dimensions in the geographic coordinate system, each of a plurality of the grid points that are positioned within the predetermined spacing to at least one of the objects in each of the two dimensions being defined as active grid points; and checking, using an updated geographic location received from a first one of the objects and the geographic locations of other ones of the objects, for an existence of a crowd by determining whether there are four or more times a predetermined threshold number of the objects that are located within the predetermined spacing in each of the two dimensions to a first one of the active grid points that is within the predetermined spacing in each of the two dimensions to the updated geographic location. - View Dependent Claims (12, 13, 14)
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15. A computer system for detecting crowds in a location tracking system, the computer system comprising:
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at least one memory device storing coordinates of geographic locations of a plurality of objects and grid points of a grid in two dimensions in a geographic coordinate system, the grid having a predetermined spacing in each dimension between the grid points; and at least one processing unit configured to detect, based on an updated geographic location received from a first one of the plurality of objects, an existence of a crowd using an amount of storage of the at least one memory device that is independent from a total number of the objects; wherein an amount of memory of the at least one memory device is linearly proportionate to the total number of objects being tracked in the location tracking system.
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16. A computer system for detecting crowds in a location tracking system, the computer system comprising:
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at least one memory device storing coordinates of geographic locations of a plurality of objects and grid points of a grid in two dimensions in a geographic coordinate system, the grid having a predetermined spacing in each dimension between the grid points; and at least one processing unit configured to detect, based on an updated geographic location received from a first one of the plurality of objects, an existence of a crowd using an amount of storage of the at least one memory device that is independent from a total number of the objects; wherein the at least one processing unit is configured to access the at least one memory device and compare the geographic locations with the grid points and define as an active grid point each of a plurality of the grid points that are positioned within the predetermined spacing to at least one of the objects in each of the two dimensions; wherein the at least one processing unit is configured to determine whether there are four or more times a predetermined threshold number of the objects that are located within the predetermined spacing in each of the two dimensions to a first one of the active grid points that is within the predetermined spacing in each of the two dimensions to the updated geographic location. - View Dependent Claims (17, 18)
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Specification