As a non-contact discharge detection method, ultraviolet (UV) imaging can rapidly, directly, and securely detect corona discharges. Therefore, UV imaging has been widely applied to power systems. To study the influences of different factors on UV corona discharge detection, two typical types of UV imagers (DayCor^®Superb and CoroCAM^®6D) were utilized. Results show that the observation angle has little impact on UV detection if no obstacles block the detection line of sight. Given that different UV imagers have different optimal imager gains, photon numbers under different gains could be calibrated to the values under optimal gains in accordance with the gain correction formula. Photon numbers decrease with the increase in the square of observation distance. Detection results under different observation distances could be corrected to the contrast distance after the detection of electrical equipment. The photon numbers of different UV imager types could be corrected in accordance with the instrumental correction factor. The results of this study can provide references to improve the applications and standardizations of UV imaging technology in corona discharge detection.