Action Recognition with Dynamic Image Networks

Understand

We introduce the concept of "dynamic image", a novel compact representation of videos useful for video analysis, particularly in combination with convolutional neural networks (CNNs).

• A dynamic image encodes temporal data such as RGB or optical flow videos by using the concept of `rank pooling'.
• The idea is to learn a ranking machine that captures the temporal evolution of the data and to use the parameters of the latter as a representation.
• When a linear ranking machine is used, the resulting representation is in the form of an image, which we call dynamic because it summarizes the video dynamics in addition of appearance.