Apparatus and a method for detecting motion within an image sequence
First Claim
1. Apparatus for detecting motion within a scene that is represented by a sequence of images, comprising:
- a flow field generator for processing said sequence of images to produce a motion flow field, wherein said flow field generator comprises an image preprocessor for producing filtered images from said sequence of images and a flow field processor for generating said motion flow field from said filtered images, wherein said image preprocessor comprises an image selector for selecting three images from said sequence of images, a first subtractor for subtracting a first image from a second image to create a first difference image, a second subtractor for subtracting said second image from a third image to create a second difference image, a first filter for filtering said first difference image to produce a first filtered image, and a second filter for filtering said second difference image to produce a second filtered image;
a flow field segmentor for extracting said motion flow field from said sequence of images; and
an alarm detector for analyzing said motion flow field to determine if said motion flow field meets an alarm criteria.
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Accused Products
Abstract
Apparatus and a concomitant method of identifying the direction of motion within a scene that is represented by a sequence of images, e.g., a series of frames in a video sequence. The apparatus contains a flow field generator, a flow field segmentor, and alarm detector and an alarm processor. The flow field generator processes the sequence of images and generates a substantially distortionless flow field representing the motion within a scene. The flow field is a vector representation of the motion of the scene that represents both the magnitude and the direction of the motion. The flow field is generated by correlating at least two frames in the sequence of images. This flow field is analyzed by a flow field segmentor to determine the magnitude and direction of motion with the scene and segment the motion information from the static portions of the scene. An alarm detector then processes the motion information to determine if an alarm should be generated based upon the motion information. The alarm processor activates an appropriate alarm response, e.g., illuminate warning lamps, sound a warning alarm, lock doors, and alert security personnel.
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Citations
17 Claims
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1. Apparatus for detecting motion within a scene that is represented by a sequence of images, comprising:
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a flow field generator for processing said sequence of images to produce a motion flow field, wherein said flow field generator comprises an image preprocessor for producing filtered images from said sequence of images and a flow field processor for generating said motion flow field from said filtered images, wherein said image preprocessor comprises an image selector for selecting three images from said sequence of images, a first subtractor for subtracting a first image from a second image to create a first difference image, a second subtractor for subtracting said second image from a third image to create a second difference image, a first filter for filtering said first difference image to produce a first filtered image, and a second filter for filtering said second difference image to produce a second filtered image; a flow field segmentor for extracting said motion flow field from said sequence of images; and an alarm detector for analyzing said motion flow field to determine if said motion flow field meets an alarm criteria. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A security system comprising:
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motion detector comprising; a flow field generator for processing a sequence of images to produce a motion flow field; a flow field segmentor, connected to said flow field generator, for extracting said motion flow field from said sequence of images; and an alarm detector, connected to said flow field segmentor, for analyzing said motion flow field to determine if said motion flow field meets an alarm criteria; a warning camera, connected to said motion detector for imaging a first area of a scene; an alarm camera, connected to said motion detector, for imaging a second area of a scene; and where said motion detector generates a warning signal when a motion flow field meets certain alarm criteria in said first area of said scene imaged by said warning camera and generates an alarm signal when a motion flow field meets certain alarm criteria in said second area of said scene imaged by said alarm camera. - View Dependent Claims (9, 10, 11, 12)
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13. A method for detecting motion within a scene that is represented by a sequence of images, comprising the steps of:
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selecting three images from said sequence of images; subtracting a first image from a second image to create a first difference image; subtracting said second image from a third image to create a second difference image; filtering said first difference image to produce a first filtered image; and filtering said second difference image to produce a second filtered image; generating a motion flow field from said first and second filtered images; extracting said motion flow field from said sequence of images; and analyzing said motion flow field to determine if said motion flow field meets an alarm criteria. - View Dependent Claims (14, 15, 16, 17)
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Specification