What is the temporal feature in video sequences?

• It refers to the temporal relationships of video events in the time space

First problem: Markov Process

a1 a2 a3 a4

44434241

34333231

24232221

14131211

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Second problem: Hidden Markov Model

• Construct a model to explain a time sequence of events

• Use the model to identify other observation sequence

HMM Elements

1. Observation sequence: O={O1,O2,…,OT}

2. Hidden states: S={S1,S2,…,SN}

3. State transition probability A={aij}

4. Observation probability B={bij}

5. Initial state distributionNitatsii 1],Pr[ 1

Chromaticity removes shading and magnitude:

),/( BGRRr )/( BGRGg

i i

ii r

rr

Observable State Sequence for a given video

• Temporal keyframe-based Summarized Video (TSV)– Efficient

– Removing frame noise

… ...

Video frame sequence

TSV