Perspectives in "electronic endoscopy". Past, present and future of fibers and CCDs in medical endoscopes.

Electronic endoscopy has undergone considerable evolution in recent years. Early instruments had poorer resolution than fiberscopes, and distorted colors significantly. The second generation of electronic endoscopes has been considerably improved, and electronic endoscopy is expected to play a major role in endoscopy in the next decade, with its enhanced teaching abilities, permanent image storage, reproduction and retrieval. An important new development has been the development of a high-resolution colonoscope & gastroscope. Electronic endoscopes are now able to produce better resolution than fiberscopes, and the future should bring further improvements in resolution with electronic instruments. A number of problems still remain to be solved with electronic endoscopy. Irregular reflection from secretions, food and blood at short focus (less than 1 cm) results in a loss of resolution, which makes electronic endoscopy particularly difficult when bleeding is brisk. Electronic endoscopes synthesize color from a strobed signal of red, blue and green in a processor. Color is dependent on brightness, and at close focus, excessive brightness in the center of the field results in erratic color reproduction. Images acquired at electronic endoscopy may be digitized for storage and processing in a computer--which, however, is not a straightforward task at the present time. Image processing in electronic endoscopy is still in its early stages, but we anticipate that new developments in early diagnosis, classification and measurement of lesions will take place. Digitized images can also be transmitted via telephone lines, and it will soon be possible to instantaneously send images across the world.