An image processing system comprising: a first pixel extracting unit that extracts a non-flat and non-edgy pixel from an image; and a haze depth estimating unit that derives a haze depth estimate value of the image based on at least two among a luminance evaluation value, a colorfulness saturation evaluation value and a contrast evaluation value of the non-flat and non-edgy pixels extracted by the first pixel extracting unit, the first pixel extracting unit extracts a flat or edgy pixel from the image, and excludes the extracted pixel from the image to extract a non-flat and non-edgy pixel, characterised by the flat or edgy pixel being judged by: acquiring a maximum value and a minimum value of pixel values of a predetermined number of pixels including a pixel of interest and other pixels that are arranged vertically and sandwich the pixel of interest as their center; and a maximum value and a minimum value of the predetermined number of pixels including the pixel of interest and other pixels that are arranged horizontally and sandwich the pixel of interest as their center; and judging the pixel of interest as a flat or edgy pixel, when the value obtained by subtracting the minimum value from the maximum value is equal to or lower than a first threshold, and when the value is equal to or higher than a second threshold that is higher than the first threshold, in at least one of the vertical direction and the horizontal direction. a first pixel extracting unit that extracts a non-flat and non-edgy pixel from an image; and a haze depth estimating unit that derives a haze depth estimate value of the image based on at least two among a luminance evaluation value, a colorfulness saturation evaluation value and a contrast evaluation value of the non-flat and non-edgy pixels extracted by the first pixel extracting unit, the first pixel extracting unit extracts a flat or edgy pixel from the image, and excludes the extracted pixel from the image to extract a non-flat and non-edgy pixel, characterised by the flat or edgy pixel being judged by: acquiring a maximum value and a minimum value of pixel values of a predetermined number of pixels including a pixel of interest and other pixels that are arranged vertically and sandwich the pixel of interest as their center; and a maximum value and a minimum value of the predetermined number of pixels including the pixel of interest and other pixels that are arranged horizontally and sandwich the pixel of interest as their center; and judging the pixel of interest as a flat or edgy pixel, when the value obtained by subtracting the minimum value from the maximum value is equal to or lower than a first threshold, and when the value is equal to or higher than a second threshold that is higher than the first threshold, in at least one of the vertical direction and the horizontal direction. acquiring a maximum value and a minimum value of pixel values of a predetermined number of pixels including a pixel of interest and other pixels that are arranged vertically and sandwich the pixel of interest as their center; and a maximum value and a minimum value of the predetermined number of pixels including the pixel of interest and other pixels that are arranged horizontally and sandwich the pixel of interest as their center; and judging the pixel of interest as a flat or edgy pixel, when the value obtained by subtracting the minimum value from the maximum value is equal to or lower than a first threshold, and when the value is equal to or higher than a second threshold that is higher than the first threshold, in at least one of the vertical direction and the horizontal direction.