1. A method for discriminating a tissue of interest, comprising: detecting an intensity of each pixel of a tissue-of-interest image obtained for each wavelength; matching an index corresponding to an image, which has a greatest intensity corresponding to each pixel, to each pixel; generating a signal weight corresponding to each pixel in consideration of a wavelength absorbed by the tissue of interest; and applying the generated signal weight of each pixel to each pixel of an image obtained with a wavelength, which is the most absorbed by the tissue of interest, to generate an image in which the tissue of interest is discriminated.