Figure 2.

(a) Probability density of z-projections. (b) L₁ and (c) L₂ values between nondiabetic control (NC; group 1) and diabetic without retinopathy (NDR; group 2) subjects. Correctly classified images in group 1 had positive L₁ values, while correctly classified images in group 2 had negative L₂ values. The larger L₁ value for an image in group 1 and the smaller L₂ value for an image in group 2 are indicators of more likely true positive and more likely true negative discrimination, respectively.