Fig. 8 shows the comparison between FID chromatogram and NIF profile. Abbott et al. [21] proposed to objectify a single odor, which panels perceived at the ODP, as averaged perceived odor frequencies. From this comparison, one inversed peak against FID chromatogram indicates one perceived odor. For example, when n = 3, if one odor of the same retention time was perceived three times, three peaks accumulate to the NIF profile (coincident response chromatogram) as shown below