The zc-axis is aligned with the plane normal
of the image plane, thereby describing the distance away
form the camera, while xc and yc-axis are parallel to image
frame such that yc is directed downwards in the image
plane and the xc-axis point from the center towards the
right in the image frame hence completing the right hand
rule. Notational a point pk in NED-frame will be denoted
pk,n, while in the body-frame it is denoted as pk,b.