A new computational model illuminates the extraordinary eyes of Phronima
Fig 6
Visual detection distance across depths showing the effect of spatially summating different numbers of ommatidia in eyes with different sampling arrangements.
Rows show the maximum detection distances of eyes that employ spatial summation and either (A–C) optimally sample visual space (Δρ:Δϕ = 1) or (D–F) oversample visual space (Δρ:Δϕ = 2.4). Each column shows the model results for (A, D) a point source, (B, E) an extended luminous object, and (C, F) an extended dark object. Extended objects were 1 cm in diameter. All targets were viewed against downwelling radiance at different depths. In all figures, the model results are shown for a single ommatidium (black), seven spatially summated ommatidia (dark grey), and 19 spatially summated ommatidia (light grey). Grey shading shows the distances and depths at which detection can occur. Model inputs were those of the medial eyes of Phronima (Table 2) and model parameters (Table 1).