Systems, devices, and methods for accurately imaging chemiluminescence and other luminescence are disclosed. A compact, flat-bed scanner having a light-tight enclosure, one or more detector bars of linear charge-coupled device (CCD) or complementary metal oxide semiconductor (CMOS) imaging chips, and high working numerical aperture (NA) optics scans closely over a sample in one direction and then the opposite direction. Averages or other combinations of intensity readings for each pixel location (x, y) between the two or more passes are averaged together in order to compensate for luminescence that varies over time. On-chip pixel binning and multiple clock frequencies can be used to maximize the signal to noise ratio in a CCD-based scanner.