LIGHT-INTENSITY MEASUREMENTS FROM DARK NOISE-ANALYSIS OF VIDEO IMAGES

It is possible to determine the absolute intensity of a light signal recorded by a video camera with automatic gain by analyzing the background part of the recorded images. The method is based on the determination of the histogram of the gray levels of the dark pixels whose inverse variance appears to be proportional to the camera gain in a large domain of light intensity. An example is given by images recorded by a charge coupled device camera in a space experiment where the light transmittivity is used as a local probe for temperature measurements.