Artifact-free countershading

The images below were generated using the artifact-free unsharp masking method (section 6.1), and adjusted to the just-objectionable countershading thresholds found in our experiments.

The optimum optical resolution for this page is 30 pixels per visual degree, which corresponds to viewing a 24" 1920x1024 display from the distance of 18.5" (47 cm).

The σ-values below each image corresponds to the width of the countershading profile and λ-values to its magnitude. Move the mouse over any of the images to see the original image without countershading enhancement.

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76

σ = 0.133 [vis deg] (= 4 px); λ = 0.333

σ = 0.329 [vis deg] (= 9.86 px); λ = 0.466

σ = 0.811 [vis deg] (= 24.3 px); λ = 0.638

σ = 2 [vis deg] (= 60 px); λ = 0.76