WLTOG: An optimization approach for wild large‐range target omnidirectional geolocation based on monocular PTZ camera

Abstract

The pan‐tilt‐zoom (PTZ) cameras are increasingly popular in urban management and resource protection due to their omnidirectional coverage and reasonable cost. Traditionally, the research of monocular camera geolocation focuses on small‐range ones with a central projection camera under ideal conditions, making it challenging to meet the requirements of omnidirectional coverage and large‐range geolocation for PTZ cameras. In this article, a wild large‐range target omnidirectional geolocation (WLTOG) algorithm was proposed. Firstly, the WLTOG algorithm is used to transform the target in a single image to the camera's optical axis, thereby obtaining the camera posture value. After that, by using a high‐order overdetermined equation, it fits the nonlinear mapping relationship between multiple pairs of PTZ camera postures and the geospatial coordinates. At last, it realizes the bidirectional calculation between pixel coordinates and geospatial coordinates. The experimental PTZ camera is mounted on a communication tower in a wild environment. Therefore, this method can be utilized to construct an omnidirectional geolocation relationship that meets the requirements of omnidirectional geolocation within 945 m based on unknown accurate internal and external orientation elements. The WLTOG algorithm is conducive to the geometric measurement of video and GIS‐augmented video surveillance.