Regan D, Hong X H
Department of Psychology, York University, Ontario, Canada.
Optom Vis Sci. 1990 Jan;67(1):49-55. doi: 10.1097/00006324-199001000-00010.
There are several visual mechanisms for analyzing spatial information additional to the much researched mechanism sensitive to luminance contrast. We describe a Snellen-type acuity test for motion-defined (MD) letters. Acuity for these MD letters collapsed at dot speeds slower than 0.05 deg/s, but acuity for contrast-defined (CD) letters was unaffected by speed over the entire 0 to 0.3 deg/s range used. Acuity was a power function of presentation duration for both kinds of letter, but the exponent was higher for MD than for CD letters. Acuity for MD letters was comparatively unaffected by dot density from 50 to 0.05%, below which it suddenly collapsed to zero. On the other hand, acuity for CD letters progressively fell as dot density was reduced from 50%, and below about 0.5% approximated acuity for MD letters.
除了对亮度对比度敏感且已得到大量研究的机制外，还有几种用于分析空间信息的视觉机制。我们描述了一种用于运动定义（MD）字母的斯内伦（Snellen）型视力测试。对于这些MD字母，当点速度低于0.05度/秒时，视力会下降，但在整个0至0.3度/秒的使用范围内，对比度定义（CD）字母的视力不受速度影响。两种字母的视力都是呈现持续时间的幂函数，但MD字母的指数高于CD字母。MD字母的视力在点密度从50%降至0.05%的范围内相对不受影响，低于该范围时视力会突然降至零。另一方面，CD字母的视力随着点密度从50%降低而逐渐下降，在约0.5%以下时接近MD字母的视力。
