6A-L1:INTRODUCTION TO MOTION

🎞️ Motion Applications

• Background Subtraction

• Shot Boundary Detection

• Motion Segmentation

  • Segment the video into multiple coherently moving objects.

🎡 MOTION AND PERCEPTUAL ORGANIZATIONS

• Gestalt psychology (Wertheimer 1880-1943)

🔡 IMPOVERISHED MOTION

• Even "impoverished" motion data can evoke a strong percept.

🏋️‍♂️ More Applications of Motion Analysis

• Mosaicing

• Segmentation of objects in space or time

• Estimating 3D structure

• Learning dynamical models - how things move

• Recognizing events and activities

• Improving video quality (motion stabilization)

👨‍💻 Motion Estimation Techniques

1. Feature-based Method

   1. Extract visual features (corners, textured areas) and track them over multiple frames.

   2. Sparse motion fields, but more robust tracking

   3. Suitable when image motion is large (more than 10s of pixels)

2. Direct, Dense Methods

   1. Directly recover image motion at each pixel from spatio-temporal image brightness variations

   2. Dense motion fields, but sensitive to appearance variations

   3. Suitable for video and when image motion is small.