基于积分球光源的能见度测量系统设计及实现

Design and Implementation of VisibilityMeasurement System Based on IntegratingSphere Light Source

同源双光路能见度仪是一种基于数字摄像法的能见度仪,其光源和光路系统会直接影响能见度的反演结果。针对系统中因光源和分光系统不稳定造成的反演误差,以积分球光源作为同源双光路能见度仪的改进光源,采用远近反射端对积分球光源进行分光,提取相机拍摄到的远近光斑并代入Koschmieder公式求解。试验结果表明:积分球光源与LED光源相比,减小了5%的均匀性误差。在不同能见度条件下,将基于积分球光源的能见度测量系统与LT-31透射式能见度仪、VPF-730散射式能见度仪进行场外比对试验,结果表明,基于积分球光源的能见度测量系统的均方根相对偏差和相对平均偏差都远小于20%,符合世界气象组织对能见度仪测量准确度的误差要求。

The single-light-source dual-optical path visibility meter is a kind of camera type visibility meters,and its light source and optical path system directly affect the accuracy of visibility inversion.In view of the error caused by the instability of the light source and the split light path in the original system,the integrating sphere is used as the improved source of the single-light-source dual-optical path visibility meter,and the near and far reflection end is used to split an integrating sphere light source.The near and far light spots captured by the camera are extracted and brought into Koschmieder′s law.The experimental results show that compared with the LED light source,the integrating sphere light source proposed in this paper reduces the uniformity error by 5%.Compared with the transmission type visibility meter LT-31and the scattering type visibility meter VPF-730under different visibility conditions,the root-mean-square(RMS)relative error and relative average error of this scheme are much less than 20%,which is in line with the WMO′s error requirement of the visibility meters.