Acuityalong

Acuityalong is a conceptual framework in visual science and computer vision for quantifying how human or machine visual acuity changes along a predefined trajectory within a stimulus or scene. The term combines acuity and along to emphasize the along-path nature of measurements.

Definition: It treats acuityalong as a function A(s) of a path parameter s that runs from 0 to 1 along a chosen trajectory. A(s) can be defined in terms of spatial frequency thresholds, contrast thresholds, or logMAR equivalents, depending on the task. Measurements are obtained by presenting stimuli that progress along the path or by tracking gaze or motion while stimuli are varied, using psychophysical or computational methods.

Measurement and methodology: Experimental protocols typically involve presenting moving or sequential targets aligned along the path, with adaptive methods (staircase, Bayesian) to estimate thresholds at selected s values. Data are fitted with smoothing or parametric models that capture spatial variation, such as eccentricity-dependent or gradient-based relationships.

Applications: Potential uses include evaluating display and interface legibility along navigation paths, optimizing VR/AR content to maintain acuity along gaze trajectories, visual rehabilitation assessment, and research into cortical magnification and peripheral processing.

History and status: The concept emerged in recent vision science literature as a way to tie local acuity to spatial position within a scene. It remains an area of active methodology, with ongoing developments in measurement techniques and computational modeling.

See also: Visual acuity, eccentricity, psychophysics, cortical magnification, gaze tracking.