To automatically prepare a fog picture in which a way that fog hung in a background is changing is expressed.
A fog picture preparing device 10 prepares a fog picture in which secularly changing fog is drawn in a background picture at the time of preparing a computer graphics(CG). This device is provided with a fog coefficient generating means for generating a fog coefficient for setting the initial value of the concentration of second-dimensional fog, and a picture synthesizing means for generating fog information in each time based on the fog coefficient and a fog changing ratio for normalizing the level of the secular change of the concentration of the fog and the color of the fog inputted from a fog parameter designating device 12, and overlapping the generated fog information on the background picture inputted from a picture inputting device 14.
IINUMA TERUAKI
YAMAJI MASATAKA
SATO AKIRA
