Electronic endoscope

A video-processor of an electronic endoscope, to which a proximal end of a video-scope and a monitor for displaying an object image are respectively connected, said video-scope having an image sensor provided at a distal end of said video-scope, on which an object image is formed, and a light guide provided throughout said video-scope, to guide light from the proximal end of said video-scope to the distal end of said video-scope, said video-processor processing image-pixel signals corresponding to said object image, read from said image sensor successively, so as to generate video signals and feed said video-signals to said monitor, said video processor comprising:

• a light source provided in said video-processor such that light, emitted from said light source, is guided through said light guide and radiates from the distal end of said video-scope;
• a luminance value calculator adapted to successively calculate a luminance value indicating brightness of said object image, on the basis of said image-pixel signals;
• a light-adjuster adapted to adjust a quantity of light radiating from the distal end of said video-scope on the basis of a difference between said luminance value and a reference value indicating a proper brightness of said object image at regular-time-intervals, such that the brightness of said object image displayed on said monitor is maintained at a constant level;
• and
• a determiner adapted to determine whether halation occurs on said object image displayed on said monitor, on the basis of said luminance value,
• wherein said light-adjuster includes a light-reducer adapted to reduce the quantity of light radiating from the distal end of said video-scope by a predetermined percentage independent of the difference between said luminance value and said reference value when halation occurs on said object image.