One of the major issues in visual science concerns the kind of visual stimuli one should use to study visual processing, and the underlying model of such slimuli. Various kinds of stimuli are used, depending on the purpose of study, i.e, bars, sinusoidal waves, random dots, textures, colored stimuli, motion signals, letters etc. Although independent dimensions of visual features should be addressed, the underlying principles remain unknown. Here, I propose the Gabor transformation as one of the answers. I review the consequence how Gabor transformation was discovered, and how it is applied in compoing Gabor visual stimuli, including the mathematical transformation of information based on the optimization method. How Gabor visual stimuli are used in visual science is also discussed.
Purpose: To compare postoperative uncorrected visual acuity (UCVA) between against-the-rule (ATR) and with-the-rule (WTR) astigmatism.
Methods: UCVA in far vision was measured in two groups of postoperative astigmatics at −1diopter (D) who had undergone keratorefractive surgery in 2008. One group had WTR axis at 0±15 degrees (171 eyes), the other had ATR axis at 90±15 degrees (124 eyes). The best UCVA (logMAR) was compared between the two groups.
Results: The spherical equivalent yielding the best UCVA of the groups was (−0.25±0.5D) for WTR and (+0.25±0.5D) for ATR. The mean and 95% confidence interval of the best logMAR of the groups were, respectively (−0.152 and −0.170 to −0.133) in WTR and (−0.168 and −0.190 to −0.146) in ATR. The difference was not statistically significant (p=0.294) and was clinically negligible.
Conclusions: The best UCVAs in postoperative astigmatism of WTR and ATR are the same, whereas the spherical equivalents yielding the best UCVA differ between the groups.
To evaluate Web Content Accessibility Guidelines (WCAG) 2.0 success criteria on luminance contrast ratio, we measured the spectral radiance for web-safe colors and calculated age-related relative luminance and contrast based on age-related spectral luminous efficacy as defined by the Japanese Industrial Standards. As a result, luminance ratio reduction by aging was observed in the bluish and greenish hue, saturation, value (HSV) hue region, especially among people in their 50s and older in the bluish region (HSV hue 240 degrees). Also, by calculating the age-related luminance contrast ratio against black, the incremental ratio of luminance contrast dispersed by aging, with 47 out of 140 colors showing 10% or more decremental ratio in their 70s. Considering the effect of aging, the WCAG 2.0 success criteria are mostly suitable for web-safe colors, as there were only a few colors that changed eligibility for WCAG 2.0, while we must be careful using colors in the blue region, due to the decrease in luminance contrast ratio. It is also recommended that we use colors with HSV value of 204 or more against a black background when presenting visual information to aged persons.