DETERMINATION OF THE QUALITY INDEX 'NONLINEARITY' OF IMAGING LUMINANCE MEASUREMENT DEVICES (ILMD)

摘要

Similarly to single-element photometers, the linearity of ILMD, i.e. the amplitude- and resolution-dependent ratio between the measured luminance of a light source and the output signal (display value) is restricted due to different nonlinear transfer functions. In contrast to photometers, in the case of which the linearity mainly depends on the linearity of the amplifier and/or the linearity of the AD converter and the linearity of the detector, the linearity of CCD cameras may also depend on the variation of the integration time, i.e. on the ability to store and transfer electron charge with nearly no losses. The aim of this paper is to discuss different methods which may be used to determine the nonlinearity of ILMDs and different approaches to generate the quality index f_(3).