ELECTRONIC ENDOSCOPE

摘要

PROBLEM TO BE SOLVED: To provide an electronic endoscope capable of improving the responsiveness as much as possible by quickly making the reproduced image luminance appropriate when controlling a diaphragm opening degree based on a histogram obtained from pixel signals of one frame. SOLUTION: This electronic endoscope is composed of a scope 10 and an image signal processing unit 12 connected thereto freely attachably and detachably. A light source 18 is provided inside the image signal processing unit and a light emitted from the source 18 is led to the scope and illuminates the front part. An image pickup sensor 14 is provided on the tip side of the scope and the histogram is developed in a histogram extraction means 64 based on luminance pixel signals for one frame or for one field obtained therefrom. A diaphragm 20 for adjusting the quantity of the light led from the light source to the scope is provided and the light quantity is adjusted corresponding to an average luminance value obtained from the data thinned out from the entire data of the histogram.