1. An information processing apparatus comprising: an estimation unit that expresses a light intensity distribution, which is obtained by irradiating light to a measurement object of a measurement target having a plurality of substances with mutually different responsive characteristics to the light on a surface and/or an inside of the measurement object, as a linear combination of light intensity distributions, which are obtained by irradiating the light to reference measurement objects, each of which has a single substance, models the light intensity distribution obtained from each of the reference measurement objects so as to follow a predetermined probability distribution, and estimates a combination coefficient of the linear combination from the light intensity distribution obtained from the measurement object of the measurement target.