A computer system is provided, the computer system executing an operation which includes: fusing first frame data generated at a first interval, with second frame data which includes a plurality of sub-frame data generated at an interval shorter than the above first interval, the second frame data being generated at a second interval longer than the above first interval as a whole; selecting, based on a reference time of the above first frame data, at least two of the above sub-frame data included in the above second frame data which are respectively different; and generating the above second frame data from the above selected sub-frame data, wherein the above fusing includes fusing the above second frame data generated from the above selected sub frame data with the above first frame data.