Trajectory data compression
First Claim
Patent Images
1. A method for more efficiently compressing locational data and for performing real-time analytics of such locational data comprisingproviding raw trajectory data of an object, the raw trajectory data relates to a physical trajectory of the object and is derived from a signal collection system;
- processing, by a processor, the raw trajectory data to identify key data points from the raw trajectory data, the key data points include primary key data points and secondary key data points, wherein identifying the key data points is based on compression parameters comprisingTmax which is the maximum time constant that when exceeded, indicates that the object is stationary,Dmin which is the minimum distance control parameter to tolerate signal noises and error,Dmax which is the maximum distance for indicating that the object is moving, andθ
min which is the minimum angle for indicating that the object is turning, the compression parameters are used todetermine if a current data point under analysis Ptc is a primary key data point, wherein a primary key data point comprises begin (B) or end (E) points, andin response to determining that the data point Ptc is not a primary key data point, determine if one or more data points in a temporary buffer (Ptemp) is a secondary key data point, wherein a secondary key data point comprises a turn (T) point which indicates that the object is turning at an angle relative to a previous data point;
removing, by the processor, data points from the raw trajectory data which are not identified as key data points (non-key data points) thereby reducing an amount of data required to characterize the physical trajectory of the object;
storing the key data points as a set of compressed trajectory data points P′
corresponding to a compressed trajectory of the object, the compressed trajectory represented by at least one segment, whereinprimary key data points define ends of the segment, andsecondary key data points are intermediate key data points between ends of the segment; and
analyzing, by the processor, the compressed data points to provide an analysis for developing traffic models, wherein the analysis comprisesdetermining accuracy and error tolerance of a data compression system by adjusting at least one of input compression parameters.
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Abstract
Disclosed is an effective and efficient compression system and technique for large amount of data. The data compression is particularly useful for compressing locational data. The compressed locational data is efficient and effective in tracing a moving object. By selecting appropriate input compression parameters, the accuracy and efficiency of the data compression can be tailored to the needs of the user.
19 Citations
20 Claims
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1. A method for more efficiently compressing locational data and for performing real-time analytics of such locational data comprising
providing raw trajectory data of an object, the raw trajectory data relates to a physical trajectory of the object and is derived from a signal collection system; processing, by a processor, the raw trajectory data to identify key data points from the raw trajectory data, the key data points include primary key data points and secondary key data points, wherein identifying the key data points is based on compression parameters comprising Tmax which is the maximum time constant that when exceeded, indicates that the object is stationary, Dmin which is the minimum distance control parameter to tolerate signal noises and error, Dmax which is the maximum distance for indicating that the object is moving, and θ
min which is the minimum angle for indicating that the object is turning, the compression parameters are used todetermine if a current data point under analysis Ptc is a primary key data point, wherein a primary key data point comprises begin (B) or end (E) points, and in response to determining that the data point Ptc is not a primary key data point, determine if one or more data points in a temporary buffer (Ptemp) is a secondary key data point, wherein a secondary key data point comprises a turn (T) point which indicates that the object is turning at an angle relative to a previous data point; removing, by the processor, data points from the raw trajectory data which are not identified as key data points (non-key data points) thereby reducing an amount of data required to characterize the physical trajectory of the object; storing the key data points as a set of compressed trajectory data points P′
corresponding to a compressed trajectory of the object, the compressed trajectory represented by at least one segment, whereinprimary key data points define ends of the segment, and secondary key data points are intermediate key data points between ends of the segment; and analyzing, by the processor, the compressed data points to provide an analysis for developing traffic models, wherein the analysis comprises determining accuracy and error tolerance of a data compression system by adjusting at least one of input compression parameters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of more efficiently compressing trajectory data comprising:
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providing raw trajectory data of an object, the raw trajectory data relates to a physical trajectory of the object; processing, by a processor, the raw trajectory data to identify key data points from the raw trajectory data, the key data points include primary key data points and secondary key data points, wherein identifying the key data points is based on compression parameters, the compression parameters comprise Tmax which is the maximum time constant that when exceeded, indicates that the object is stationary, Dmin which is the minimum distance control parameter to tolerate signal noises and error, Dmax which is the maximum distance for indicating that the object is moving, and θ
min which is the minimum angle for indicating that the object is turning;removing data points from the raw trajectory data which are not identified as key data points (non-key data points) thereby reducing an amount of data required to characterize the physical trajectory of the object; storing the key data points as a set of compressed trajectory data points P′
corresponding to a compressed trajectory of the object, the compressed trajectory represented by at least one segment, whereinprimary key data points define ends of the segment, and secondary key data points are intermediate key data points between ends of the segment; and analyzing, by the processor, the compressed data points to provide an analysis for developing traffic models, wherein the analysis comprises determining accuracy and error tolerance of a data compression system by adjusting at least one of input compression parameters. - View Dependent Claims (14, 15)
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16. A system for more efficiently compressing trajectory data comprising:
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an input data source for receiving raw trajectory data characterizing physical movement of an object from a trajectory data collector; a preprocessor for pre-processing the raw trajectory data; a compressor for compressing the raw trajectory data to identify key data points from the raw trajectory data based on compression parameters thereby reducing an amount of data required to characterize the physical movement of the object, the compression parameters comprising Tmax which is the maximum time constant that when exceeded, indicates that the object is stationary, Dmin which is the minimum distance control parameter to tolerate signal noises and error, Dmax which is the maximum distance for indicating that the object is moving, and θ
min which is the minimum angle for indicating that the object is turning, wherein the compressor comprises,a primary module for identifying if a current data point (Ptc) is a primary key data point, the primary module stores Ptc in a temporary buffer (Ptemp) if Ptc is not a primary key data point, and a secondary module for processing Ptc and data points in Ptemp to determine if data point or data points in Ptemp are secondary key data points; and an output data source for storing the key data points identified by the compressor as a set of compressed trajectory data points P′
corresponding to a compressed trajectory, the compressed trajectory represented by at least one segment, whereinprimary key data points define ends of the segment, and secondary key data points are intermediate key data points between ends of the segment; and analyzing, by the compressor, the compressed data points to provide an analysis for developing traffic models, wherein the analysis comprises determining accuracy and error tolerance of a data compression system by adjusting at least one of input compression parameters. - View Dependent Claims (17, 18)
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19. A non-transitory computer usable medium having a computer readable program code tangibly embodied therein, the computer readable program code adapted to be executed by a processor to implement a method of more efficiently compressing trajectory data comprising:
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providing raw trajectory data of an object, the raw trajectory data relates to a physical trajectory of the object; processing the raw trajectory data by the processor to identify key data points from the raw trajectory data, the key data points include primary key data points and secondary key data points, wherein identifying the key data points is based on compression parameters comprising Tmax which is the maximum time constant that when exceeded, indicates that the object is stationary, Dmin which is the minimum distance control parameter to tolerate signal noises and error, Dmax which is the maximum distance for indicating that the object is moving, and θ
min which is the minimum angle for indicating that the object is turning, the compression parameters are used todetermine if a current data point under analysis Ptc is a primary key data point, wherein a primary key data point comprises begin (B), end (E) or stationary (S) points, and in response to determining that the data point Ptc is not a primary key data point, determine if one or more data points in a temporary buffer (Ptemp) is a secondary key data point, wherein a secondary key data point comprises a turn (T) point which indicates that the object is turning at an angle relative to a previous data point; removing data points from the raw trajectory data which are not identified as key data points (non-key data points) thereby reducing an amount of data required to characterize the physical trajectory of the object; storing the key data points as a set of compressed trajectory data points P′
corresponding to a compressed trajectory of the object, the compressed trajectory represented by at least one segment, whereinprimary key data points define ends of the segment, and secondary key data points are intermediate key data points between ends of the segment and further comprises a move (M) point; and analyzing, by the processor, the compressed data points to provide an analysis for developing traffic models, wherein the analysis comprises determining accuracy and error tolerance of a data compression system by adjusting at least one of input compression parameters. - View Dependent Claims (20)
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Specification