Optical flow
From Free net encyclopedia
Optical flow is a concept for considering the motion of objects within a visual representation. Typically the motion is represented as vectors originating or terminating at pixels in a digital image sequence.
Optical flow is useful in pattern recognition, computer vision, and other image processing applications. It is closely related to motion estimation and motion compensation. Often the term optical flow is used to describe a dense motion field with vectors at each pixel, as opposed to motion estimation or compensation which uses vectors for blocks of pixels, as in video compression methods such as MPEG. Some consider using optical flow as collision avoidance and altitude acquisition system for micro air vehicles (MAVs).
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Some methods for determining optical flow
- Phase correlation (inverse of normalized cross power spectrum)
- Block correlation (sum of absolute differences, normalized cross-correlation)
- Gradient Constraint–based registration
- Lucas Kanade Method
- Horn Schunck Methodde:Optischer Fluss