155. S3D (Separable 3D CNN)

I’ve learned about S3D(Separable 3D CNN) today so I like to share it here.

S3D helps solve three challenges for video analysis.

  1. How to understand spatial information. (Recognizing the appearance of an object)
  2. How to understand temporal information. (Such as context and causation through time)
  3. The trade-off between model complexity and inference speed.

Before this, 3DCNN was thought of as a promising way to tackle the challenges above, but it was prone to overfitting and it became complex and expensive.

By using a SEPARABLE CONVOLUTION in the earlier layers, S3D significantly improves performance compared with previous state-of-the-art 3D video classification models.