Electronic endoscope

An electronic endoscope comprising:

• a video-scope having an image sensor, provided at a distal end of said video-scope, on which an object image is formed;
• a video-processor, to which a proximal end of said video-scope is connected, that processes image-pixel signals corresponding to said object image, successively read from said image sensor;
• a light source provided in said video-processor such that light, emitted from said light source, is guided through said video-scope and radiates from the distal end of said video-scope;
• a stop, provided between said light source and the proximal end of said video-scope, that adjusts a quantity of light radiating from the distal end of said video-scope;
• a luminance generator that successively generates luminance signals from said image-pixel signals;
• a calculator that successively calculates a representative value, associated with a brightness of said object image, on the basis of said luminance signals;
• a light-controller that adjusts the brightness of said object image at regular time-intervals, by controlling said stop on the basis of said representative value and a predetermined reference value;
• and
• a determiner that determines whether said representative value coincides with a preceding representative value from a preceding calculation;
• said light-controller not driving said stop when said representative value coincides with said preceding representative value and driving said stop when said representative value does not coincides with said preceding representative value.