Real-time feature extraction from video stream data for stream ...

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Real-time feature extraction from video stream data for stream ...

2.2. Shot Boundary Detection

then be divided into segments with the same topic which may consist of multiple scenes.

Scenes themselves might then be segmented into shots and on the lowest level shots

consist of single frames (identical to single images). Figure 2.2 shows an example of this

hierarchy based on a fictitious ”ZDF Sportstudio” show.

Figure 2.2.: Hierarchical temporal segmentation of a television broadcast.

When talking about video content broadcasted over television, the first level of this

hierarchy (show level) is given by the available EPG data. Furthermore the decoded

video stream consists of single frames, so that the lowest level of the hierarchy (frame

level) is of course given as well. The task of segmenting a video into meaningful sections

hence aims of the identification of shots, scenes and segments. This can be done topdown

by trying to split a show into parts that are so diverse that it is unlike they belong

together.Another option is going bottom-up by grouping frames together to receive a

segmentation on the shot level and than grouping shots together to receive scenes or

segments. As almost all existing approaches operate bottom-up, I am first going to focus

on the task of shot boundary detection (section 2.2). In the following section 2.3, I will

introduce approaches that allow to group the identified shots together.

2.2. Shot Boundary Detection

For any segmentation task on each level of the hierarchy, a segmentation of the video

stream into constituent shots will be necessary. This learning task is equivalent to the task

of finding shot boundaries in video sequences (shot boundary detection, also known as

temporal video segmentation). As this is a basic task a lot of approaches for automatically

recognizing and characterizing shot boundaries have been developed in the past 20 years.

Definition 2 (Shot (Traditional)) Originally a shot is an image sequence consisting

of one or more frames and recorded contiguously during a single operation of the camera.

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