Video processing system for modifying a zone in successive images
First Claim
1. A method of modifying video images which belong to a sequence and which are mutually correlated, said method comprising the steps of:
- storing a representation of a target to be replaced with a stored model in said images;
storing a plurality of successive ones of said images of said sequence in a buffer memory;
searching for the target in the stored images by pattern recognition until the target is found with reliability in at least one of said stored images;
carrying out reverse and forward predictions as to the location of the target in said stored images which precede and follow the image where the target is found, based on an evaluation of global changes of the stored images, whereby precise identification of the location of the target in a particular one of said images is achieved even when only part of the target is available within the particular image; and
replacing said target with a respective representation of the model.
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Accused Products
Abstract
A method and an apparatus for substituting a representation of a target, identified by a set of points of interest stored in a memory, with a matching representation of a predetermined stored pattern in successive TV frames are described. The apparatus has a buffer for storing successive frames of a sequence, constituting a first in-first out memory having a length sufficient for storing all frames over a period of some seconds. Points of interest in each current frame are extracted and an attempt is made to find at least a subset of the extracted points of interest matching with a respective subset of the stored set. Global motion of the image between successive frames is evaluated and the location of the target in the frames following and preceding a frame in which the pattern is found is predicted. A target finder locates the target in the frames where it is found, based on the prediction. Each partial or complete representation of the target in each frame, where found, is replaced with a representation of the stored pattern after the stored pattern has been subjected to size and perspective transformation computed from a comparison between the points of interest in the representation of the target in the respective frame and the respective stored points of interest.
101 Citations
16 Claims
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1. A method of modifying video images which belong to a sequence and which are mutually correlated, said method comprising the steps of:
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storing a representation of a target to be replaced with a stored model in said images; storing a plurality of successive ones of said images of said sequence in a buffer memory; searching for the target in the stored images by pattern recognition until the target is found with reliability in at least one of said stored images; carrying out reverse and forward predictions as to the location of the target in said stored images which precede and follow the image where the target is found, based on an evaluation of global changes of the stored images, whereby precise identification of the location of the target in a particular one of said images is achieved even when only part of the target is available within the particular image; and replacing said target with a respective representation of the model.
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2. A method of substituting a representation of a target, identified by a set of points of interest stored in a memory, with a matching representation of a predetermined stored pattern of same geometrical shape, in successive TV frames of a sequence of frames taken from a video camera, said method comprising the steps of:
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(a) storing successive frames of said sequence in a buffer, (b) extracting points of interest from each current frame of the sequence in turn and attempting to find at least a subset of said extracted points of interest from each current frame which matches with a respective subset of said stored set of points of interest, (c) evaluating motion of said camera between each current frame where such a match is found and following and preceding frames in the sequence, based on a global comparison between contents of the frames; (d) predicting locations of said target in said following and preceding frames in the sequence from the evaluated motion, (e) automatically searching for said target in said following and preceding frames in said sequence using the predicted locations; and (f) in each searched frame, replacing the representation of said target with a representation of said stored pattern after said stored pattern has been subjected to transformation computed from a comparison between a plurality of points of interest in said representation of the target in the respective frame and the stored points of interest. - View Dependent Claims (3, 4, 5, 6)
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7. An apparatus for substituting a representation of a target, identified by a set of points of interest stored in a memory, with a matching representation of a predetermined stored pattern of same geometrical shape, said substituting to take place in successive TV frames of a sequence of frames taken from a video camera, said apparatus comprising:
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buffer means for storing successive frames of said sequence, said buffer means comprising a first in-first out memory having a length sufficient for simultaneously storing a predetermined plurality of said frames over a period of some seconds; means for extracting points of interest in each current said frame of the sequence in turn and attempting to find at least a subset of the extracted points of interest matching with a respective subset of the stored set; means for evaluating global motion between successive frames and for predicting a location of the target in the frames following and preceding a frame in which the pattern is found; target finding means for precisely locating the target in the frames where it is found, based on the prediction; replacer means for replacing a partial or complete representation of the target in each frame where it is found, with a representation of the stored pattern after the stored pattern has been subjected to size and perspective-transformation computed from a comparison between some at least of the points of interest in the representation of the target in the respective frame and the respective stored points of interest. - View Dependent Claims (8, 9, 10, 14, 15)
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16. A method of manipulating video images which belong to a sequence and which are mutually correlated, said method comprising the steps of:
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storing a representation of a target to be identified in said images; storing a plurality of successive ones of said images of said sequence in a buffer memory; searching for the target in the stored images by pattern recognition until the target is found with reliability in one at least of said stored images; carrying out reverse and forward predictions as to the location of the target in those of said stored images preceding and following the image where the target is found, based on an evaluation of global changes of the images, whereby precise identification of the location of the target in a particular one of said images is achieved even when only part of the target is available within the particular image. - View Dependent Claims (11, 12, 13)
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Specification