6B-L3:HIERARCHIAL LK

LK = Lucas Canade

Reduce the Resolution

• Optical Flow: Aliasing

Aliasing

Imagine that our object is moving 7 pixels, estimating the motion is harder than moving 1 pixel. Hovewer, what if we reduce the resolution?

Multi Scale

Image Sub Sampling

If we use the below technique and if we zoom to the last picture and resize it, It might look like blurring effect but this is not we want it is just aliasing.

SOLUTION: Filter the image then subsample like below.

Image Pyramids

Computing The Laplacian Pyramid

Apples and Oranges (Blending)

Start with Something similar to Lucas-Kanade

• Gradient constancy

• region matching

• energy minimization with smoothing term

• keypoint matching (long-range)