1. An image processing system to remove haze from an image, comprising: a luminance evaluation value deriving unit that derives a luminance evaluation value of an at least partial region of an image; a saturation evaluation value deriving unit that derives a saturation evaluation value of the region; a contrast evaluation value deriving unit that derives a contrast evaluation value of the region; a haze depth estimating unit that derives a haze depth estimate value of the image based on the luminance evaluation value, the saturation evaluation value, and the contrast evaluation value; and a haze removing unit that removes haze from the image based on the haze depth estimate value; wherein the luminance evaluation value is an average luminance value of the region, the saturation evaluation value is an average saturation value of the region, the contrast evaluation value is a contrast value of the region, and the haze depth estimating unit derives a higher value for the haze depth estimate value as the average saturation value decreases, and derives a higher value for the haze depth estimate value as the contrast value decreases.