A cue-free method to probe human lighting biases.
A cue-free method to probe human lighting biases.
复制标题
一种探测人类照明偏差的无提示方法。
作者：
Mazzilli G
人们很容易将阴影图案视为三维形状。由于从阴影中提取形状时的一般浅浮雕模糊性，人们必须同时估计表面的形状和光源的性质。在许多情况下，图像中的线索不足以解决存在的所有模糊性，在这种情况下，人类视觉系统可能会采用基于生态和经验的许多先验假设之一。其中一个假设是从上方照明先验。这里，在没有照明方向的外在线索的情况下，模糊的阴影图案被解释为好像被观察者头部上方的光源照亮。对这种先验的研究通常使用模糊的刺激并观察感知偏差。一定程度的暗示是这种方法所固有的。参与者反复看到阴影刺激，并被要求对它们进行形状判断，而不管他们是否真的感知到任何3D形状。我们希望通过建立模板来更直接地访问人们的照明先验，他们将在没有任何视觉提示的情况下检测阴影对象。为此，我们采用了图像分类的方法。
People readily perceive patterns of shading as 3-D shapes. Owing to the generalised bas-relief ambiguity when extracting shape from shading, people must simultaneously estimate the shape of the surface and the nature of the light source. In many cases cues in the image will be insufficient to resolve all of the ambiguities present, and in such cases the human visual system may employ one of a number of prior assumptions based on ecology and experience. One such assumption is the lighting-from-above prior. Here, in the absence of extrinsic cues to lighting direction, ambiguous shading patterns are interpreted as if lit by a light source that is above the observer’s head. Studies of this prior typically use ambiguous stimuli and observe perceptual biases. A degree of cueing is inherent to such methods. Participants see the shaded stimuli repeatedly and are asked to make shape judgments about them regardless of whether or not they actually perceive any 3-D shape. We wanted to access people’s lighting prior more directly by establishing the template they would employ to detect a shaded object in the absence of any visual cue to object shape. To this end, we adopted a classification image approach.