Cast Shadow Illusions
Cast Shadow Illusions
复制标题
投射阴影幻象
DOI：
10.1093/acprof:oso/9780199794607.003.0020
复制
发表时间：
2014
影响因子：
2
通讯作者：
P. Mamassian
中科院分区：
文献类型：
--
作者：
D. Kersten;P. Mamassian
阴影无处不在，但它们通常不被注意到。然而，我们确实一直在使用它们的后果。图1A显示了两幅图，每幅图的棋盘背景前面都有一个绿色正方形。这两幅画的不同之处只在于广场上投射的阴影。由于这些差异，右边的方块看起来比左边的方块离背景更远。通过在投射的阴影中添加运动，对深度感知的影响可以相当显著。移动阴影，使正方形在图像中保持固定，会导致正方形似乎在深度上移动(请参阅：http://youtu.be/ig2CV1TLn5A).只有仔细观察，人们才能确信正方形在相框内根本没有移动。特别是，广场没有改变大小，如果它确实在深度移动，它就应该改变大小。阴影似乎给视觉系统制造了一个悖论。一方面，它们作为深度线索非常有用，但它们的不显眼表明，视觉系统可能有很好的理由去除它们。1投射阴影可以与“附着”或“形式”阴影区分开来(见Mamassian等人，1998；Castiello，2001)。对象上附加的阴影是背离光源的变暗表面。曲面上的投射阴影是由对象阻挡光线照射到该曲面上而形成的暗区域。当对象的一部分阻挡光线照射到同一对象的另一部分时，也可以创建投射阴影。为简单起见，在本章中，“阴影”一词通常指的是“投射的阴影”。
Shadows are everywhere, but they usually go unnoticed. We do, however, use their consequences all the time. Figure 1A shows two pictures each with a green square in front of a checkerboard background. The two pictures differ only in the cast shadows of the square. Because of these differences, the right square appears to be further from the background than the left square. By adding motion to the cast shadow, the effect on the perception of depth can be made quite striking. Moving the shadow, leaving the square fixed in the image, results in the square appearing to move in depth (see: http://youtu.be/ig2CV1TLn5A). It is only with scrutiny that one is convinced that the square is not moving at all within the picture frame. In particular, the square is not changing size, as it should if it was indeed moving in depth. Shadows seem to create a paradox for the visual system. While on the one hand they can be quite useful as cues for depth, their unobtrusiveness suggests that there may be good reasons for a visual system to get rid of them.1 Cast shadows can be distinguished from “attached” or “form” shadows (see Mamassian et al., 1998; Castiello, 2001). An attached shadow on an object is the darkened surface that faces away from the light source. A cast shadow on a surface is the dark area created by an object blocking light onto that surface. A cast shadow can also be created when part of an object blocks light onto another part of the same object. For simplicity, in this chapter, the word “shadow” will usually refer to “cast shadow”.
空间布局的感知类别。
DOI：
10.1098/rstb.1997.0099
发表时间：
1997
期刊：
Philosophical transactions of the Royal Society of London. Series B, Biological sciences
影响因子：
--
作者：
Kersten,D
通讯作者：
Kersten,D