1. An image processing apparatus comprising: a generation unit adapted to generate adaptation point image data indicating an adaptation point corresponding to each pixel of original image data; a tone conversion unit adapted to convert a tone of the original image data based on the adaptation point image data, generating converted image data; an addition unit adapted to add the adaptation point image data to the converted image data; wherein said generation unit generates the adaptation point image data by performing a smoothing process on the original image data; and an acquisition unit which acquires an observation condition of an original image represented by the original image data, wherein said generation unit generates the adaptation point image data by performing a smoothing process based on the observation condition on the original image data.