Electronic endoscope for highlighting blood vessel

An electronic endoscope comprising:

• a color signal formation circuit that forms predetermined color signals based on signals captured by an image pickup element;
• a binarization circuit that inputs color signals other than a red signal output from said color signal formation circuit and generates binarized image signals;
• an edge detection circuit that inputs binarized signals output from said binarization circuit and detects blood vessel positions in an image;
• a blood vessel redetection circuit that redetects the blood vessel position signals output from said edge detection circuit by a clock signal slower than the image processing clock signal;
• and
• a chroma correction circuit that adjusts chroma of the blood vessel image based on the blood vessel position signals output from said blood vessel redetection circuit and said color signals.

An electronic endoscope comprising:

• a color signal formation circuit that forms a predetermined color signal based on signals captured by an image pickup element;
• a differentiating circuit that differentiates predetermined color signals other than a red color signal obtained at said color signal formation circuit and generates a differential signal;
• a gain circuit that amplifies the differential signal output from said differentiating circuit;
• and
• a blood vessel highlighting circuit that amplifies at least a red signal other than said predetermined color signals based on the differential signal output from said gain circuit to highlight the blood vessel.