Anstis S, Ho A
Department of Psychology, UC San Diego La Jolla 92093-0109, USA.
Vision Res. 1998 Feb;38(4):523-39. doi: 10.1016/s0042-6989(97)00167-3.
The changes in apparent brightness or color, induced into a test spot by a surround, can be greatly enhanced either by flickering the test spot between two luminances, or by binocularly fusing a pair of test spots of different luminances. Simultaneous contrast, in which a white surround makes a grey spot look darker, is greatly enhanced if the spot (not the surround) flickers between black and white. Colour contrast is likewise enhanced by chromatic flicker: on a blue surround, a grey spot looks slightly yellowish, but a yellow/blue flickering spot looks strongly yellow. Temporal successive contrasts, or negative afterimages, are also enhanced by flickering the test field. The negative afterimage of a half-white, half-black rectangle looked dark grey and light grey when projected on a grey test field, but it looked almost black and almost white when projected on a test field that flickered between black and white. Coloured negative afterimages were also enhanced by projecting them on a chromatic flickering test field. We examined the combination rules for pairs of luminances which were presented either successively as flicker or else dichoptically (and fused binocularly). The brightness averaging functions for spatial increments (light spots) on dark surrounds were quasi-linear for binocular fusion but quadratic for flicker. For spatial decrements (dark spots) on white surrounds, the brightness averaging functions were strongly nonlinear winner-take-all for both binocular fusion and flicker. We also found temporal analogues of Fechner's [(1860). Elements of psychophysics. New York: Holt, Rinehart, Winston, 1966] paradox and Levelt's [(1965). British Journal of Psychology, 56, 1-13] dichoptic contour effect. We conclude that the visual rules for combining luminance excursions, whether in flicker or binocular fusion, favour disproportionately the spot with the higher contrast.
由周围环境引起的测试点表观亮度或颜色的变化，通过在两种亮度之间闪烁测试点，或双眼融合一对不同亮度的测试点，可得到极大增强。同时对比（白色周围环境使灰色斑点看起来更暗），如果斑点（而非周围环境）在黑色和白色之间闪烁，这种对比会大大增强。颜色对比同样可通过色度闪烁得到增强：在蓝色周围环境中，灰色斑点看起来略带黄色，但黄色/蓝色闪烁斑点看起来则强烈呈现黄色。时间上的相继对比或负后像，也可通过闪烁测试区域得到增强。一个半白半黑矩形的负后像，投射在灰色测试区域上时看起来是深灰色和浅灰色，但投射在黑白之间闪烁的测试区域上时，它看起来几乎是黑色和几乎是白色。彩色负后像投射在色度闪烁测试区域上时也会得到增强。我们研究了以闪烁或双眼分视（并双眼融合）方式相继呈现的亮度对的组合规则。对于暗背景上的空间增量（亮点），双眼融合时亮度平均函数近似线性，而闪烁时为二次函数。对于白色背景上的空间减量（暗点），双眼融合和闪烁时亮度平均函数均为强烈非线性的胜者全得。我们还发现了费希纳（1860年。《心理物理学纲要》。纽约：霍尔特、莱因哈特和温斯顿，1966年）悖论和莱尔特（1965年。《英国心理学杂志》，56卷，1 - 13页）双眼分视轮廓效应的时间类似物。我们得出结论，无论是在闪烁还是双眼融合中，组合亮度变化的视觉规则都不成比例地偏向对比度更高的斑点。
