IMPROVED COLOR REPRODUCTION OF ELECTRONIC ENDOSCOPES

Image quality from electronic endoscopes is poor compared with that fr om conventional optical endoscopes that use color film. Our goal is to improve the image quality, particularly the color reproduction of ele ctronic endoscopes. To achieve our goal, we have developed the endosco pic spectrophotometer to measure the spectral reflectance of gastric m ucous membranes. Three hundred and ten spectra have been analyzed by p rincipal component analysis. The results indicate that the reflectance spectra can be adequately described using only three principal compon ents. Based on the above experimental result, we show that the spectra l reflectance of gastric mucous membranes can be calculated from the R , G, B signals of conventional electronic endoscopes. Therefore, spect ral reflectance of all pixels in gastric mucous membranes taken by ele ctronic endoscopes can be estimated within less than the average color difference Delta E(uv)() = 2.66 in the L*u*v* color space. Computer simulations of the color reproduction of electronic endoscopes were pe rformed, and the resulting spectral characteristics under various illu minants are described and analyzed.