Indirect measurement of the intensity of incident light by the light transmission fluctuation method.

The light transmission fluctuation method is a simple and useful method for in situ and in-line measurement of particle size and concentration. To accomplish the measurement, it is necessary to know the intensity of incident light or background signal I(0). However, measuring I(0) during in-line applications is hard. In this Letter, an algorithm is proposed to indirectly measure I(0) based on the variation of transmitted light signals. Experiments have been carried out to verify the algorithm and the maximum deviation between premeasured I(0) and indirectly measured I(0)' is less than 2.5%.