中文摘要：

为使日盲紫外成像仪在不同距离下检测到的放电光子数具有可对比性，需将结果修正到统一的观测距离下。为此，选择了3种放电模型作为研究对象，利用CoroCAM504紫外成像仪实验研究了不同放电强度下光子数随观测距离的变化特性。对检测结果进行了幂函数和指数函数拟合分析，在此基础上提出了光子数的距离修正经验公式。研究表明：由于外界干扰和紫外成像仪的计数误差，放电太弱或观测距离较远时，随观测距离d增加光子数不再减小甚至还有增大的趋势；当光子数〉10且数值高于d／2时可认为是有效数值；在4～50m的观测距离范围内，有效光子数与观测距离之间满足幂函数关系，3种放电模型的幂指数都近似为1．222。测试表明提出的光子数距离修正经验公式修正精度较高，可满足现场工程检测需要。

英文摘要：

To reasonably compare the discharge photon cotmt measured at different observation distances using solar-blind ultraviolet （UV） imagers, it is necessary to normalize the results with a common distance. Hence, we selected three discharge models as the objects, and used CoroCAM504 UV imager to measure discharges with different intensities at different distances in laboratory. Moreover, we analyzed the variation of photon count regarding to different observa- tion distances, fitted the results with power functions and exponential functions, and proposed an empirical formula for the distance correction of photon count. The results show that because of the external interference and the UV imager＇s count error, when the discharge is too weak or the observation distance is far, the photon count no longer reduces but tends to increase with increasing distance. When the photon count is more than 10 and more than d/2, where d is the observation distance, it can be taken as an effective value. Within the range of observation distances 4-50 m, the relation between effective photon count and observation distance approximately meets power functions, the power exponent of which is about 1.222 for all the three tested discharge models. Further tests show that the proposed empirical formula is accurate enough to satisfy the needs of field engineering detection.