An image processing device, comprising: a signal intensity extraction unit configured to separate a reflected light component and an illumination light component from an input image and to calculate signal intensity on the basis of the reflected light component and the illumination light component; a peripheral region reference value calculator configured to calculate a peripheral region reference value based on the signal intensity of a peripheral region located around a small region of interest; an emphasis degree determination unit configured to determine an emphasis degree of the signal intensity so as to increase the signal intensity of the small region; and a conversion output unit configured to correct the signal intensity using the emphasis degree and to output an output image using the corrected signal intensity, wherein the signal intensity is defined as a reflection rate calculated on the basis of a reflected light component and an illumination light component separated from the input image input to the image processing device, the small region is defined as a region which is a part of the input image and comprises at least one pixel, and the emphasis degree is determined based on a predetermined value so as to be monotonically non-decreasing with respect to a difference between the peripheral region reference value and the predetermined value; and the predetermined value T satisfies conditions of: S ≤ T ≤ OL, when R ≥ 0, and UL ≤ T ≤ S, when R < 0, wherein R represents the signal intensity of the small region of interest, S represents the peripheral region reference value, T represents the predetermined value, and OL and UL respectively represent an upper limit and a lower limit of the signal intensity of the output image that is output by the conversion output unit. a signal intensity extraction unit configured to separate a reflected light component and an illumination light component from an input image and to calculate signal intensity on the basis of the reflected light component and the illumination light component; a peripheral region reference value calculator configured to calculate a peripheral region reference value based on the signal intensity of a peripheral region located around a small region of interest; an emphasis degree determination unit configured to determine an emphasis degree of the signal intensity so as to increase the signal intensity of the small region; and a conversion output unit configured to correct the signal intensity using the emphasis degree and to output an output image using the corrected signal intensity, wherein the signal intensity is defined as a reflection rate calculated on the basis of a reflected light component and an illumination light component separated from the input image input to the image processing device, the small region is defined as a region which is a part of the input image and comprises at least one pixel, and the emphasis degree is determined based on a predetermined value so as to be monotonically non-decreasing with respect to a difference between the peripheral region reference value and the predetermined value; and the predetermined value T satisfies conditions of: S ≤ T ≤ OL, when R ≥ 0, and UL ≤ T ≤ S, when R < 0, wherein R represents the signal intensity of the small region of interest, S represents the peripheral region reference value, T represents the predetermined value, and OL and UL respectively represent an upper limit and a lower limit of the signal intensity of the output image that is output by the conversion output unit.