Calibration of a high dynamic range, low light level visible source

摘要

Usage of image intensified (I2) and other low light level devices have grown considerably over the past decade1,2 As the systems have become more common place, the demand for production line test equipment has also grown. Accurate measurements of device response are a key part of determining acceptable system operation. However, differences in the spectral response of the unit under test (UUT) devices and the control detector; and the spectral distribution of the source, can lead to errors in test accuracy. These errors can be compounded by spectral variation in the source (or color temperature shifts) as a function of attenuation. These issues are often further confused by test system requirements that are not consistent with the desired parameter to be measured. For example, source requirements are often specified in illuminance while the UUT actually measures irradiance. We report on the calibration of a large dynamic range light source test system (> 7 orders), and discuss output compensation approaches for systems which control in a band different than the UUT being tested