An integrated circuit includes a photosensor array with subrange cells that photosense within respective subranges of an energy range. An optical signal and the array move relative to each other, and, for segments of their relative movement, sets of subrange cells photosense within subranges that are different. For example, a scanning device can cause relative scanning movement. The optical signal can be produced by illuminating a two-dimensional object. The photosensed quantities for a part of the optical signal can be used to produce spectral information for the part.