Digital photography visiometer systems have been well developed and widely used in visibility observation at daytime.However

the observation at nighttime is often limited due to errors and fluctuations associated with the poor uniformity of illumination and instability of lighting-sources at nighttime which might be affected by power-supply sources and environmental temperature changes.In this study

we proposed a specific light-emitting-diode (LED) system as nighttime lighting-source which is anti-shaking

stable

and has a short response time.The uniformity of illumination has been significantly improved by using these high-density arrays of LED lighting sources with four illumination reflectors installed around the LED lighting-source box and one diffuser in the front.To reduce the fluctuations and improve the stability of the power-supply system

we designed a high-stable power supply system with constant-voltage-drive mode and constant self-feedback current drive circuit.Target-oriented algorithms have been developed to minimize the errors due to changes in illumination of lighting sources caused by temperature changes.