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

As an omnidirectional monocular camera, the pan-tilt-zoom (PTZ) camera has been widely employed in urban governance, forest fire protection, traffic supervision due to its omnidirectional coverage and inexpensive cost. Traditional monocular camera geolocation research focuses on small-range geolocation with a central projection camera under ideal conditions, making it difficult to meet the requirements of omnidirectional coverage and large-range geolocation for PTZ cameras. In view of this, this paper proposed a wild large-range target omnidirectional geolocation (WLTOG) algorithm. Firstly, the WLTOG algorithm transforms the target in a single image to the camera's visual center, obtaining the camera posture value. Then, it fits the nonlinear mapping relationship between multiple pairs of PTZ camera postures and the geospatial coordinates by using high-dimensional overdetermined equation, and finally realizes the bidirectional calculation between pixel coordinates and geospatial coordinates. The experimental PTZ camera is mounted on a communication tower in wild hilly environment. This method can be used to construct an omnidirectional geolocation relationship that meets the requirements of omnidirectional geolocation within 945m based on unknown accurate internal and external orientation elements, and low requirements for wild hardware installation. The WLTOG algorithm is conducive to the geometric measurement of a single image, GIS-augmented video surveillance, and 3D object recognition.