Emissive chart for imager calibration

Abstract

Each and every color imaging device should be custom calibrated both to enhance image processing algorithms and to produce pleasing and faithful images of the captured scenes or medias. Custom calibrations, however, are usually not performed because calibration instruments are either too slow to be used on the manufacturing line or the instruments lack the necessary accuracy. We have developed a calibration instrument that enables both fast and accurate imager calibrations. The instrument is based on emissive narrow-band light sources—light emitting diodes—arranged in a grid pattern or chart configuration. We refer to the instrument as the emissive calibration chart or the EC chart. We compare the emissive calibration chart to other calibration instruments, which include reflective charts, like the Macbeth ColorChecker or DC charts, and monochromators. The results demonstrate that custom calibrations of each and every imager could be accurately determined on the manufacturing line using the emissive calibration chart.