| abstract |
A region of interest in a living body is exposed to excitation light, which causes it to produce fluorescence. The fluorescence is separated with respect to desired wavelength ranges and detected. A first detector detects an entire fluorescence component or a fluorescence sum component, which is the sum of a fluorescence component of a comparatively short wavelength region and a fluorescence component of a comparatively long wavelength region. A second detector detects a fluorescence component of a comparatively long wavelength region or a fluorescence difference component, which is the difference between a fluorescence component of a comparatively short wavelength region and a fluorescence component of a comparatively long wavelength region. The output from the first detector and the output from the second detector are divided by each other. The fluorescence intensity depending upon the distance with respect to the region of interest is thus corrected such that no error may occur in making an operation. |