An optical system in solar-blind UV for corona discharge detection

A bi-spectral camera for visible and solar-blind UV (240nm-280nm) was developed for detecting the corona discharge. Due to the UV light generated by corona discharge is very weak, so an optical system by careful calculation was designed for the UV band. The UV optical system was schemed with the focal length of 200mm, relative aperture of 1:2.77 and the FOV of ±2°. The assembly of UV optical system also introduced in paper. A new method used to solve the problem of corona point not calibration in non-central of FOV in fusion image. After calibrating, the position of corona discharge can be observed accurately by overlaying UV image of the corona on a visible light image of the background. The bi-spectral optical system was accomplished and tested in the lab. Results showed that the FOVs of visible light and solar-blind UV optical systems were matched well.