The present invention is an electronic-endoscope apparatus for compensating
for lack of light quantity caused by a delayed response from a light
shielding mechanism when an all-pixel reading system is used. In the case
of, for example, a moving image, this apparatus reads pixel mix data out
from a CCD to reproduce motions faithfully. For a still image, this
apparatus reads out all pixels obtained by the CCD during a single
exposure period using a light shielding period set by a light shielding
plate, and outputs this data to a mixing circuit via memories to form a
pixel mix signal. This configuration enables a high-quality still image to
be obtained. In this case, however, the light quantity may be insufficient
due to a delayed response from the light shielding plate. Thus, during the
exposure period for still-image formation, the lamp voltage is increased
above a normal amount or the diaphragm aperture is increased in order to
compensate for the shortage of light quantity. In addition, this light
quantity compensation can be achieved by amplifying a video signal or
controlling the increase of the electronic shutter time.
