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

摘要

A method for obtaining a horizontal distance between a camera and a target as a horizontal distance between a center point of an optical system of a camera and a ground landing point of a target is disclosed. The method includes steps (a) through (c). In the step (a), the relative target angle as an angle formed by the camera-target connecting line connecting the center point of the optical system of the camera and the ground landing point of the target with respect to the ground is obtained. In step (b), the height of the camera as the height of the center point of the optical system of the camera with reference to the vertical position of the ground on which the target landed is obtained. In step (c), the result of dividing the height of the camera by the tangent value of the relative target angle is set as the horizontal distance between the camera and the target.