To provide means which is capable of improving the detection efficiency of a culture medium by removing a mark image of a character or the like written on a culture vessel, from an observation image.
A computer is made achieve: a step S1 of illuminating the inside of a culture vessel which houses a culture medium for use for cultivation of a culture with transmitted light and has a prescribed mark drawn on a bottom surface thereof or a lid surface opposite to the bottom surface, which is to be an installation surface of the culture, by using light-transmissive ink, and acquiring an observation image obtained by imaging the inside of the culture vessel with an imaging apparatus by using transmitted light; a step S2 of utilizing color space information which a prescribed mark image reflected in the observation image has, to generate an image resulting from exclusion of reflection of the prescribed mark from the observation image; and a step S3 of outputting the image resulting from exclusion of reflection of the prescribed mark.
ITO HIROSHI
YANO KAZUHIRO
