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Computer Science Engineering Lee Sang Seon
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Introduction Basic notions for temporal video boundaries Micro-Boundaries Macro-Boundaries Mega-Boundaries Conclusion Q & A
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Brief definition of Temporal Video Boundary technique → Examine the temporal boundary problem at different levels of video content structure analysis Why we need Temporal Video Boundary technique? Show example
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Insufficient metadata opening ending
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Detailed metadata opening ending actor winners awards ending
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Video contains three types of modalities (i) Visual (ii) Audio (iii) Textual Each modality has three levels (i) low-level(ii) mid -level(iii) high-level → levels describe the amount of details described in each modality in terms of granularity and abstraction
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For each modality and for each level there if a set of attributes. These can be formalized as vectors:
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Adding to this, given a set of vectors → their average value denote the vector
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Local method → the difference is computed between consecutive frames Global method → the difference if computed over a series of frames
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Definition Boundaries associated to the smallest video units for which a given attribute is constant or slowly varying The attribute can be any feature in the visual, audio, or text domain
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Data structure that represents the color information of a family of frames. Set of frames that exhibits uniform features = Frame histogram
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Histogram difference using L1 metrics Bin-wise histogram intersection Total number of color bins used Histogram of previous frame Histogram of current frame
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1. Contiguous with zero memory → A new frame histogram is compared with previous frame histogram 2. Contiguous with limited memory → A new frame histogram is compared with previous family histogram
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3. Non contiguous with unlimited memory → A new frame histogram is compared with all previous family histograms within the same video. 4. Hybrid → First a new frame histogram is compared using the contiguous frames and then generated family histograms are merged using non contiguous case.
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Definition Boundaries between collections of video micro- segments that are clearly identifiable organic parts of an event defining a structural (action) or thematic (story) unit Video : collection of stories that may or may not be interconnected → Macro-Boundaries detection = Segmenting stories textual cues audio cuesvisual cues
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Unimodal segment detection A video segment exhibits same characteristic over a period of time Multimodal segment detection A video segment exhibits a certain characteristic taking into account attributes from different modalities
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Partition a continuous bitstream of audio data into non-overlapping segments Classification Seven mid-level audio categories Using low-level audio features Audio segmentation & classification Text transcript Extracted from either the closed captions or speech-to- text conversion Segmented and categorized with respect to a predefined topic list Frequency-of-word-occurrence metric is used
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Pre-merging Steps Uniform segment detection Intra-modal segment clustering Attribute template determination Dominant attribute determination Template application Descent Methods Goal : Create macro- boundaries that are more accurate than the boundaries produced by individual modalities.
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Text segment Audio segment Video segment
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Single descent with intersecting union Single descent with intersection Single descent with secondary voting attributes Single descent with conditional union
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Definition Boundaries between collections of macro- segments that exhibit different structural and feature consistency (e.g. different genres) Example Commercial detection method
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Features that can aid in determining the location of the commercial break Triggers Features that can determine the boundaries of the commercial break Verifiers
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Time interval between detected black frames as triggers Used as verifiers Letterbox change High cut rate(= low cut distance)
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Type of boundariesMethodsExample Micro-boundariesFrame & Family histogram comparing and merging Visual scene segmentation Macro-boundariesSingle modality segmentation & Multimodal segmentation Multimodal story segmentation Mega-boundariesTrigger & VerifierCommercial detection
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