For a process and an apparatus for loading fibers contained in a pulp suspension with calcium carbonate, a calcium oxide andor a medium containing calcium hydroxide is fed to the pulp suspension, and the so treated pulp suspension is further charged in several reactors with pure carbon dioxide or a medium containing carbon dioxide. In particular embodiments, high-frequency modulation in the range of from about 1. The disclosed compounds may include radioactive atoms. The electronic device also applies thresholding to the score map to generate a detection mask. The control portion controls the display device at appropriate timing with an opening and closing cover closed, to display in text the first color information and the second color information detected by the color detection portion.