Angle of the hand to the camera

Angle of the hand to the camera

To find the angle of the user’s hand relative to the camera, we calculated the normal to the triangle of the hand we previously added. We used NumPy to find the cross product between 2 vectors of the triangle. The benefit of using a triangle is that it’s always flat, so there is only one possible normal vector. We intend that when the angle is detected to have surpassed a certain threshold value, the user is ready to switch to a different display. A benefit of calculating the normal for use in this way is that though it needs to be done every fame, it is a simple calculation for the system to perform, meaning that it has minimal effect on the system’s overall performance.

This video demonstrates the visualisation of the user’s hand, its landmarks, the triangle constructed from them, and the angle we have calculated from the normal of that triangle, shown in the bottom right in green.