1. An image processing system 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; and 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.