1. An image processing apparatus comprising: a processor connected to a memory and configured to execute: a color conversion unit that performs color conversion to convert an original image to a luminance image having a luminance component of the original image as a pixel value and to a chromaticity image having a chromaticity component of the original image as a pixel value; an illumination image generation unit that generates an illumination image having an illumination component of the luminance image as a pixel value from the luminance image; a reflectance image generation unit that generates a reflectance image having a reflectance component of the luminance image as a pixel value, the reflectance component of the luminance image being calculated by multiplying the luminance component of the original image and an inverse of the illumination component of the original image; a luminance reproduction image generation unit that enhances the reflectance component of the luminance image based on the luminance image and the reflectance image to generate a luminance reproduction image reproduced with being improved visibility of the luminance image; and an inverse color conversion unit that performs conversion inverse to the color conversion performed by the color conversion unit on the luminance reproduction image and the chromaticity image, wherein the reflectance image generation unit also includes a stabilized reflectance calculation section that calculates a stabilized reflectance component of the original image, by correcting the reflectance component of the luminance image.