PURPOSE: To sufficiently perform correction for the response delay of stimulated phosphorescence light in practical use without limiting a dynamic range by inputting a logarithmic image signal obtained by inputting an analog image signal outputted from a photodetector to a logarithmic amplifier to a differential corrector, and performing the differential correction of the signal.

CONSTITUTION: The analog image signal SA obtained by receiving the stimulated phosphorescence light 19 with the photodetector 21, after being inputted to a logarithmic converter 24 first and the logarithmic image signal SL being obtained, is inputted to the differential corrector 25. In other words, the dynamic range of a signal logarithmically compressed by directly performing the logarithmic compression of the analog image signal SA obtained by the photodetector 21 is decreased. Thereby, no limitation for the dynamic range for whole of a light reception circuit due to the differential correction is generated, and also, it is possible to sufficiently correct the response delay of the stimulated phosphorescence light 19 in practical use by performing the differential correction.