Fig. 4. The influence of photopigment OD on the normalized cell count. The upper two plots show the data for modeled deuteranomalous (left) and protanomalous (right)
observers viewing the Nascimento, Ferreira, and Foster (2002) scenes. The lower two plots are for the eight Foster, Nascimento, and Amano (2004) scenes. The three surfaces
in each plot correspond to peak separations of 0, 3, and 6 nm (see labels), and are produced by averaging the normalized cell count across the eight scenes in each set (see
text). The error bar shown in the lower right corner of each plot represents the maximum standard deviation of the average taken across the eight scenes.