Line-spread functions for the human visual system may be psychophysically measured using spatial patterns consisting of a central line flanked on either side by a line of lower contrast. It is shown that two different line-spread functions may be measured at a given eccentricity by using two different forms of temporal modulation in presenting the three line patterns. One of these linespread functions is relatively sustained, while the other has a more transient nature. The properties of both types of line-spread function have been measured as a function of eccentricity near the fovea. Using a mathematical description of these line-spread functions and spatial probability summation, it is possible to predict thresholds for cosine gratings of appropriate spatial frequencies as a function of the number of cycles viewed. The results also indicate that there must be both broader and narrower line-spread functions at each eccentricity with properties that cannot be directly measured using the three-line stimulus configuration. © 1978.
Wilson, H. R. (1978). Quantitative characterization of two types of line-spread function near the fovea. Vision Research, 18(8), 971–981. https://doi.org/10.1016/0042-6989(78)90025-1