  Intensified charge coupled device (ICCD) cameras are widely used in various
applications such as microscopy, astronomy, spectroscopy. Often they are used
as single-photon detectors, with thresholding being an essential part of the
readout. In this paper, we measure the quantum efficiency of an ICCD camera in
the single-photon detection mode using the Klyshko absolute calibration
technique. The quantum efficiency is obtained as a function of the threshold
value and of the wavelength of the detected light. In addition, we study the
homogeneity of the photon sensitivity over the camera chip area. The experiment
is performed in the autonomous regime, without using any additional detectors.
We therefore demonstrate the self-calibration of an ICCD camera.
