A New Representation of the Contrast Sensitivity Function for Human Vision

Abstract

This paper presents a new mathematical representation of the contrast sensitivity function for the human visual system. It is based on optimal smoothing spline fits to vertical and oblique contrast sensitivity measurements. Unlike most of the approximations in current use, which assume isotropy, this new representation incorporates the dependence on orientation revealed by the measurements. One of the uses of the representation is demonstrated by applying it to an example luminance field. Keywords: human vision, contrast sensitivity, luminance fields 1 Introduction The psychophysical response of the human visual system to spatial variations in a perceived luminance field is generally believed to be characterized by a contrast sensitivity function (CSF) which measures the threshold ability to detect such variations as a function of the spatial frequencies in the horizontal and vertical directions. The CSF is measured by observing sinusoidal gratings with varying contrasts and recordin..