Face detection technology is now commmonplace in digital cameras. In fact, digital cameras can now recognize a face and, if you instruct it to do so, it will use face recognition to focus on that face in a group.
Now, researchers at Oxford University have developed software that can recognize different human interactions, such as a hug, a kiss, a high five or a handshake. Based on the angle of the heads, the distance between the persons and the direction of motion of the tracked people, the software can predict the type of interaction.
This will allow us to search quickly through videos for such interactions involving one or both persons.