An electronic endoscope apparatus has an illumination unit for irradiating light of red, light of green and light of blue on an object for photographing in predetermined order at a predetermined period; an image signal generation unit for receiving reflection light from the object, generating...http://www.google.co.uk/patents/US5686958?utm_source=gb-gplus-sharePatent US5686958 - Electronic endoscope apparatus with noise suppression circuit
