Method and apparatus for detecting abrupt and gradual scene changes in image sequences
First Claim
1. A method of determining scene changes in a sequence of visual information-bearing frames, comprising the steps of:
- (a) dividing a first digitized frame into a first plurality of regions and a second digitized frame into a second plurality of regions that respectively correspond in location to the first plurality of regions;
(b) block-matching the regions of the first digitized frame to the regions of the second digitized frame to produce regional match signals that represent a likelihood that the regions of the first digitized frame contain visual information substantially similar to respective matching regions of the second digitized frame;
(c) ordering, to obtain an ordered sequence, the regional match signals beginning with a best regional match signal defining a best match and ending with a worst regional match signal defining a worst match;
(d) averaging together a predetermined number of the regional match signals that are selected in the ordered sequence of step (c) beginning with the best match signal, to obtain an instantaneous match (IM) signal, said IM signal providing a criteria for determining whether the first digitized frame represents a scene different from a scene represented by the second digitized frame; and
(e) indicating a scene change when the IM signal meets a predetermined decision criterion.
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Abstract
A method is capable of detecting both abrupt and gradual scene changes. Consecutive frames of an image sequence (e.g., a video program) are first acquired and digitized. The images are subdivided into a plurality of rectangular regions. Block matching is performed between the current frame and the Dth previous frame to determine match signals that represent the likelihood that the regions of the first frame contain visual information substantially similar to respective matching regions of the second frame. The match signals are ordered beginning with the match signals defining the best match and ending with the match signals defining the worst match. The first S match signals are selected and averaged together, to obtain an instantaneous match (IM) signal S is user definable and is greater than zero and less than or equal to the number of regions into which each frame is divided. The IM signal provides a criteria for determining whether the first frame belongs to a scene different from the second frame. Finally, a scene change is indicated when the IM signal meets certain decision criteria.
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Citations
27 Claims
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1. A method of determining scene changes in a sequence of visual information-bearing frames, comprising the steps of:
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(a) dividing a first digitized frame into a first plurality of regions and a second digitized frame into a second plurality of regions that respectively correspond in location to the first plurality of regions; (b) block-matching the regions of the first digitized frame to the regions of the second digitized frame to produce regional match signals that represent a likelihood that the regions of the first digitized frame contain visual information substantially similar to respective matching regions of the second digitized frame; (c) ordering, to obtain an ordered sequence, the regional match signals beginning with a best regional match signal defining a best match and ending with a worst regional match signal defining a worst match; (d) averaging together a predetermined number of the regional match signals that are selected in the ordered sequence of step (c) beginning with the best match signal, to obtain an instantaneous match (IM) signal, said IM signal providing a criteria for determining whether the first digitized frame represents a scene different from a scene represented by the second digitized frame; and (e) indicating a scene change when the IM signal meets a predetermined decision criterion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of determining scene changes in a sequence of visual information-bearing frames, comprising the steps of:
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(a) digitizing at least first and second frames of the sequence; (b) dividing the first frame into a first plurality of regions and the second frame into a second plurality of regions respectively corresponding in location and size to the first plurality of regions of the first frame; (c) block-matching by (i) determining values of a first match distance between a first region of the first plurality of regions and a plurality of regions of the same size as said first region within a portion of the second frame encompassing the corresponding region in the second frame; and (ii) finding a minimum value among said values, said minimum value corresponding to the location of a matching region of the second frame that is defined relative to the location of the corresponding region in the first frame, said matching region being a region of the second frame most likely to contain visual information substantially similar to the first region of the first frame; (d) calculating an average value of all the values of the first match distance and normalizing the minimum value of the first match distance by dividing said minimum value by said average value to obtain a normalized minimum value, said normalized minimum value representing the likelihood that the matching region contains information substantially similar to the first region of the first frame. - View Dependent Claims (20, 21, 22, 23, 24)
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25. A method of determining scene changes in a sequence of visual information-bearing frames, said method comprising the steps of:
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comparing in a sequential order a plurality of pairs of frames to generate an instantaneous match (IM) signal representing a similarity between the frames of each pair; temporally filtering the IM signal to generate a cumulative match (CM) signal; and indicating a scene change when the IM signal and the CM signal meet a predetermined decision criterion.
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26. Apparatus for determining scene changes in a sequence of visual information-bearing frames, comprising:
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means for comparing in a sequential order a plurality of pairs of frames to generate an instantaneous match (IM) signal representing a similarity between the frames of each pair; means for temporally filtering the IM signal to generate a cumulative match (CM) signal; and means for indicating a scene change when the IM signal and the CM signal meet certain decision criteria.
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27. Apparatus for determining scene changes in a sequence of visual information-bearing frames, comprising:
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(a) means for dividing a first digitized frame into a first plurality of regions and a second digitized frame into a second plurality of regions that respectively correspond in location to the first plurality of regions; (b) means for block-matching the regions of the first digitized frame to regions of the second digitized frame to produce regional match signals that represent a likelihood that the regions of the first digitized frame contain visual information substantially similar to respective matching regions of the second digitized frame; (c) means for ordering the regional match signals beginning with a best regional match signal defining a best match and ending with a worst regional match signal defining a worst match; (d) means for averaging together a predetermined number of the best regional match signals that are selected in the ordered sequence obtained by said ordering means, beginning with the best match signal, to obtain an instantaneous match (IM) signal, said IM signal providing a criteria for determining whether the first digitized frame represents a scene different from a scene represented by the second digitized frame; and (e) means for indicating a scene change when the IM signal meets a predetermined decision criterion.
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Specification