1. A method for determining a height of a camera, the camera at a fixed vertical height positioned above a reference plane, an axis of a lens of the camera at an acute angle with respect to a perpendicular of the reference plane, the method comprising the steps of: receiving from the camera, a multiplicity of images of a multiplicity of different people; determining, by one or more processors, vertical measurement values of the multiplicity of images of the multiplicity of different people; determining, by one or more processors, a first statistical measure associated with a statistical distribution of the vertical measurement values; transforming, based on one or more processors, known heights of people from a known statistical distribution of heights of people, with respect to the first statistical measure, to normalized measurements of known heights of people, based in part on a focal length of the lens of the camera, the acute angle of the camera, and a division operator present in an objective function of differences between the normalized measurements of known heights of people and the vertical measurement values; and determining, by one or more processors, the fixed vertical height of the camera, based at least on minimizing the objective function of the differences between the normalized measurements of known heights of people and the vertical measurement values.