Method of acquiring horizontal distance between camera and target, and camera and surveillance system adopting the method

摘要

Exemplary embodiments disclose a method of acquiring a horizontal distance between a camera and a target, which is a horizontal distance between a central point of an optical system of the camera and a ground landing point of the target. The method includes acquiring a relative target angle using an angle between a ground and a camera-target connection line which connects the central point of the optical system of the camera and the ground landing point of the target, acquiring a height of the camera using a height of the central point of the optical system of the camera on a basis of a vertical position of the ground landing point of the target, and setting a quotient of the height of the camera divided by a tangent value of the relative target angle as the horizontal distance between the camera and the target.