Linear system based, qualitative independent motion detection from compressed mpeg surveillance video
First Claim
1. A method for detection of independent motion of a plurality of objects presented in a time sequence of images acquired from different perspectives, comprising:
- a) processing the plurality of images with an automated processor to generate a linear system representing the plurality of objects in the form of a matrix D having at least three dimensions stored in a memory;
b) analyzing the stored matrix D with an automated processor to qualitatively determine the consistency of said linear system based on a relationship of respective rank of the matrix D an augmented matrix DB, substantially without quantitatively solving said linear system consistency being represented as a decision; and
c) outputting the consistency decision, representing whether or not there is independent motion between the plurality of objects represented in the time sequence of images.
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Abstract
The present invention features a qualitative method to detect independent motion revealed in successive frames of a compressed surveillance MPEG video stream using linear system consistency analysis without decompression of the stream, identifying the segments containing independent motion in a real-time or faster manner, for the retrieval of these segments. The linear system is constructed using the macroblocks of MPEG compressed video frames. The normal flow value of the macroblock is obtained by taking the dot product between the macroblock gradient vector, computed by averaging the four block gradient vectors, and the motion vector of this macroblock. The normal flow value is filtered for inclusion in the linear system, and the statistic of the matrices of the resulting linear system is determined, filtered to screen out false negatives and outliers, and used to determine the presence or absence of independent motion.
159 Citations
20 Claims
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1. A method for detection of independent motion of a plurality of objects presented in a time sequence of images acquired from different perspectives, comprising:
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a) processing the plurality of images with an automated processor to generate a linear system representing the plurality of objects in the form of a matrix D having at least three dimensions stored in a memory; b) analyzing the stored matrix D with an automated processor to qualitatively determine the consistency of said linear system based on a relationship of respective rank of the matrix D an augmented matrix DB, substantially without quantitatively solving said linear system consistency being represented as a decision; and c) outputting the consistency decision, representing whether or not there is independent motion between the plurality of objects represented in the time sequence of images. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of detecting independent motion in a stream of digitally compressed video data, the steps comprising:
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a) selecting a pair of video frames from a stream of digitally compressed video data representing a three dimensional scene; b) automatically building a linear system representing the three-dimensional scene for said pair of video frames using at least a three-dimensional to two-dimensional affine transform in which parallel lines remain parallel after affine transformation, and a change in camera position with respect to objects represented in the pair of video frames does not render said linear system inconsistent; c) automatically analyzing said linear system represented in a matrix D to qualitatively determine the consistency thereof, substantially without quantitatively solving said linear system, based on an equivalence of a respective rank Rank(D) of the matrix D and rank Rank(Db) of an augmented matrix Db, the consistency being represented as a decision; and d) storing the decision in a memory, wherein;
Dξ
=b, - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. An apparatus for detection of independent motion of a plurality of objects presented in a time sequence of images acquired from different perspectives, comprising:
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a) a processor operating on a data flow in at least in real time, to produce a sequence of outputs corresponding to a current image and a prior image, configured to; receive and process the current image in conjunction with the previously received prior image, to generate a linear system representing the plurality of objects represented in the images in the form of a matrix D having at least three dimensions stored in a memory; analyze the stored matrix D to determine the qualitative consistency of the linear system based on a relationship of respective Rank of the matrix D and the Rank of an augmented matrix Db, substantially without quantitatively solving the linear system and output the consistency decision after determination, representing whether or not there is independent motion between the plurality of objects represented in the time sequence of images. - View Dependent Claims (18, 19, 20)
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Specification