These two videos introduce the analysis of visual motion and focus on the computation of a velocity field that captures the movement of features in the changing two-dimensional image. The first video describes motion information that can be measured directly from the image, which consists of the components of motion in the direction perpendicular to moving edges. The second video elaborates on how the full two-dimensional velocity field can be computed from these motion components, assuming that objects may undergo pure translation across the image. It also introduces he smoothness constraint that embodies the idea of computing a velocity field with minimal variation. The application of this constraint gives rise to behavior that is similar to some motion illusions. Finally, the second video also touches on the neural processing of motion in area MT in monkey visual cortex.

The technical development presented in these videos relies on some simple vector operations. A concise introduction to these operations can be found in the online text, Introduction to Linear Algebra, Chapter 2 on Basic Vector Operations

Videos

The following links take you to the videos on YouTube:

• Introduction to Visual Motion Analysis (31:24)
• Computing an Image Velocity Field (18:29)

The video files are also stored in our shared folder on Google Drive, named motion_intro.mp4 (456 MB) and
velocity_field.mp4 (400 MB).

Video Transcripts

The following pdf files provide transcripts of the videos:

• Measuring Image Motion (pdf)
• Computing the Velocity Field (pdf)

The above pdf files are also stored in the shared folder on Google Drive.

Slides

The following pdf files provide the slides presented in the videos:

• Visual Motion Analysis Slides (pdf)
• Computing the Velocity Field Slides (pdf)

The above pdf files are also stored in the shared folder on Google Drive.