| abstract |
In an electronic endoscope system including a video scope having a solid-state image sensor that successively produces a frame of red, green, and blue image-pixel signals, a difference value is calculated between a value of each of corresponding central red, green, and blue image-pixel signals and an average of values of circumferential image-pixel signals surrounding the central image-pixel signal. When the respective values of the central red and green image-pixel signals are smaller than the corresponding averages of values, they are decreased in proportion to the absolute values of the corresponding difference values. When the value of the central blue image-pixel signal is smaller than the corresponding average of values, it is increased in proportion to the absolute value of the corresponding difference value. |