Vernier and letter acuities are both susceptible to degradation by image motion. In a previous study, we showed that the worsening of Vernier acuity for stimuli moving up to 4 degrees/s is accounted for primarily by a shift of visual sensitivity to mechanisms of lower spatial frequency. The purposes of this study were to extend the previous results for Vernier acuity to higher stimulus contrast...

PURPOSE To determine the nature and limits of visual improvement through repetitive practice in human adults with naturally occurring amblyopia. METHODS A key measure the authors used was a psychophysical estimate of Vernier acuity; persons with amblyopia have marked deficits in Vernier acuity that are highly correlated with their loss of Snellen acuity. The experiment consisted of three phas...

Many computational models of normal vernier acuity make predictions based on the just-noticeable contrast difference. Recently, Hu, Klein and Carney [(1993) Vision Research, 33, 1241-1258] compared vernier acuity and contrast discrimination (jnd) in normal foveal viewing using cosine gratings. In the jnd stimulus the test grating was added in-phase to the (sinusoidal) pedestal, whereas in the v...

The goal of this study was to evaluate the mechanisms underlying Vernier acuity, over a range of spatial scales using narrow-band Vernier stimuli and oblique masking. Specifically, the test stimuli consisted of a pair of vertical ribbons of horizontal cosine grating with a vertical Vernier offset between the ribbons. These stimuli have two important advantages for studying Vernier acuity: (1) t...

This study deals with the core design of a PM vernier machine considering modulation flux effects, and the comparative investigation on volume and performance characteristics of the vernier over conventional PM machines are addressed. To these ends, for a PM vernier machine in operation at the base-speed, the flux density equations for teeth and yokes considering the flux modulation effects are...

PURPOSE An objective measure of positional acuity is desirable in the nonverbal clinical population. This study was conducted to investigate the specificity of the vernier VEP as a measure of positional acuity, evaluating the potential confound of asymmetric motion responses that may be present in some groups of patients. These motion responses could masquerade as position-specific responses, s...

Dragging is one of the most useful and popular techniques in direct manipulation graphical user interfaces. However, dragging has inherent restrictions caused by pixel resolution of a display. Although in some situations the restriction could be negligible, certain kinds of applications, e.g., real world applications where the range of adjustable parameters vastly exceed the screen resolution, ...

Vernier acuity in human infants is more than two orders of magnitude poorer than in adults and does not appear to reach adult levels until well beyond the first postnatal year. One source of these developmental differences in vernier acuity may be the presence of levels of intrinsic blur that are higher in infants than in adults. We investigated this hypothesis by measuring vernier acuity in 3-...

We characterize a class of spatio-temporal illusions with two complementary properties. Firstly, if a vernier stimulus is flashed for a short time on a monitor and is followed immediately by a grating, the latter can express features of the vernier, such as its offset, its orientation, or its motion (feature inheritance). Yet the vernier stimulus itself remains perceptually invisible. Secondly,...

Comments on: variation in vernier acuity with age Li, Edwards, and Brown (2000) recently reported variation in vernier acuity with age in Vision Research. We have addressed this issue using somewhat different test displays, test conditions, and paradigms. The paper by Li et al., kindly cites a number of papers presented by our research group; here we add only related non-There seems to be a sub...