CSF model - Log-parabola contrast sensitivity function from Lesmes et al. (2010), "Bayesian adaptive estimation of the contrast sensitivity function: The quick CSF method." The four parameters (gain, peak frequency, bandwidth, truncation) define the curve shape. The multifocal IOL profile adds a Gaussian dip to model diffractive energy loss at mid-frequencies.
Sample profiles - The four profiles are illustrative examples based on published normative and clinical data; they do not represent fits to individual patient data. Young adult: Owsley, Sekuler & Siemsen (1983), "Contrast sensitivity throughout adulthood," Vision Research; Lesmes et al. (2010). Early cataract: Hess & Woo (1978), "Vision through cataracts," IOVS; Elliott & Situ (1998), "Visual acuity versus letter contrast sensitivity in early cataract," Vision Research. Uncorrected myopia: optical defocus effects per Atchison & Smith (2000), Optics of the Human Eye. Multifocal IOL: Montés-Micó & Alió (2003), "Distance and near contrast sensitivity function after multifocal intraocular lens implantation," J Cataract Refract Surg; Leyland & Zinicola (2003), "Multifocal versus monofocal intraocular lenses in cataract surgery," Ophthalmology.
Object sizes - Golf ball: USGA Rules of Golf (diameter 42.67 mm, dimple ~3.5 mm). Hi-vis vest: ANSI/ISEA 107-2020 (5 cm retroreflective tape). Highway signs: FHWA MUTCD Series E(Modified) (16-inch uppercase, 20% stroke width). Pedestrian: anthropometric averages (shoulder width ~45 cm, head ~25 cm). Deer: whitetail shoulder height ~1 m; D'Angelo et al. (2023).
Contrast values - Michelson contrast computed from published surface reflectance data. Daytime values derived from material albedo against typical backgrounds. Night retroreflective values based on ASTM E810 standard practice and FHWA-HRT-07-040 retroreflectivity report.
Fourier demand model - Broadband features modeled as step-edge stimuli: Sreq(f) = sqrt(1 + (π f θ)²) / C. Texture features use a Gaussian bandpass model. Framework follows Campbell & Robson (1968) and Watson & Ahumada (2005).