1. A method for determining a height of a camera, the camera at an unknown fixed vertical height positioned above a reference plane, and having 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, by one or more processors, over a specified time period, a multiplicity of images of a multiplicity of people of unknown height within a field of view of the camera; determining, by one or more processors, vertical measurement values of the multiplicity of images of the multiplicity of people of unknown height, wherein each vertical measurement value includes a pixel count along a vertical axis of an image of the multiplicity of images of the multiplicity of people of unknown height; receiving, by one or more processors, heights of a multiplicity of people from a statistical distribution of known heights of people; transforming, by one or more processors, the known heights of the multiplicity of people from the statistical distribution of known heights of people to normalized vertical measurement values that includes a pixel count, based at least 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; performing, by one or more processors, the objective function to sum differences between the pixel count of the vertical measurement values of the multiplicity of images and the pixel count of the normalized vertical measurement values of the heights of the multiplicity of people from the statistical distribution of the known heights of people, wherein the objective function includes an estimate of the fixed vertical height of the camera, and a transformation matrix to convert the known heights of people to normalized vertical measurement values; and determining, by one or more processors, the fixed vertical height of the camera by adjusting within the objective function, the estimate of the fixed vertical height of the camera, until a result of the objective function is minimized.