Image Processing: What are occlusions?

Question

I\'m developing an image processing project and I come across the word occlusion in many scientific papers, what do occlusions mean in the context of i

Answer 1

The problem of occlusion is one of the main reasons why computer vision is hard in general. Specifically, this is much more problematic in Object Tracking. See the below figures:

Notice, how the lady's face is not completely visible in frames 0519 & 0835 as opposed to the face in frame 0005.

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And here's one more picture where the face of the man is partially hidden in all three frames.

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Notice in the below image how the tracking of the couple in red & green bounding box is lost in the middle frame due to occlusion (i.e. partially hidden by another person in front of them) but correctly tracked in the last frame when they become (almost) completely visible.

Picture courtesy: Stanford, USC