1. An image processing apparatus configured to convert an input image to generate an output image having image shitsukan different from the image shitsukan of the input image by using an adjusting unit capable of individually adjusting various different physical image characteristics extracted from the input image and interactively adjusting the various different physical image characteristics, the apparatus comprising: a first numerical converting unit configured to be represented by a hierarchical model having a first level defining a relationship between the image characteristics and latent sensation received by humans from an image and a second level defining a relationship between the latent sensation and the shitsukan, in correspondence with human shitsukan recognition structure, the first level and the second level being different from each other, and configured to convert various different image-characteristic parameters quantifying the image characteristics to various different low-order sensitivity parameters quantifying latent sensations experienced by humans when viewing an image, wherein the various different low-order sensitivity parameter calculated from the output image are converted by the first numerical converting unit to approach numerical values satisfying a predetermined relationship; and a second numerical converting unit configured to be represented by the hierarchical model and to convert the various different low-order-sensitivity parameters to high-order-sensitivity parameters quantifying shitsukan for different materials depicted in an image, wherein the high-order-sensitivity parameters calculated from the output image are converted by the first numerical converting unit and the second numerical converting unit to approach predetermined numerical values.