A method and apparatus for calibrating an apparatus that acquires a sequence of radiographic images and correcting images of an object under observation. The microlens is disposed on a light-emitting surface of the organic EL element. The first cross-section surface is at a position closer to the photoelectric conversion element rather than the second cross-section surface, and is larger than an area of the second cross-section surface, so as to guide an incident light into the photoelectric conversion element without reflection. Further, by feeding the amount of fluctuation in transfer function over time by the function back to the estimation of a previous-stage linear filter, and thus reducing the weight for a time band in which the transfer function of a linear filter estimated value fluctuates, the influence causing a decrease in estimation accuracy of the transfer function can be reduced. The present invention also provides a process for producing eukaryotic microbial lipids.