The role of mutual illumination in gradient formation
The role of mutual illumination in gradient formation
复制标题
相互照明在梯度形成中的作用
DOI：
10.1167/6.6.246
复制
发表时间：
2010
影响因子：
1.8
通讯作者：
Bloj M
中科院分区：
文献类型：
--
作者：
Bloj M
心理物理学（Bloj et al., Nature, 402; Gilchrist & Jacobsen, Perception, 13）和计算(Funt & Drew, IEEE PAMI, 15; Nayar et al., Int。[J] Comp Vis, 6)研究假设相互照明（由场景中表面反射的光引起的间接照明）为颜色和形状感知提供线索。我们之前已经证明，RADIANCE可以用来准确地模拟场景的色度和亮度（Ruppertsberg & Bloj, JOSA-A, in press）。在这里，我们使用这个渲染包来研究和分析相互照明是如何随着光线和表面位置的变化而变化的，以努力理解视觉系统可以获得哪些潜在的线索来恢复场景布局和颜色。研究场景包括由两张不同铰链角度和不同照明角度的卡片制成的角，以及圆柱体和其他物体。对于角，给定照明角度的色度轮廓的散点图在CIE色度平面上形成一条直线，随着照明角度的增加，色度平面有系统地向“更白”的区域移动。亮度曲线的斜率变得更陡，整体亮度水平增加。对于圆柱体场景，得到的色度轮廓在色度平面上接近一条直线，亮度轮廓是非线性的。总之，我们发现所涉及的物体和光线的颜色决定了颜色梯度的色度曲线，而亮度曲线传达了几何信息，包括照明角度和/或物体形状。
Psychophysical (Bloj et al., Nature, 402; Gilchrist & Jacobsen, Perception, 13) and computational (Funt & Drew, IEEE PAMI, 15; Nayar et al., Int. J Comp Vis, 6) studies have postulated that mutual illumination (indirect illumination due to light reflected by surfaces in a scene) provides cues for colour and shape perception. We have previously shown that RADIANCE can be used to accurately simulate the chromaticity and luminance of scenes (Ruppertsberg & Bloj, JOSA-A, in press). Here, we use this rendering package to study and analyse how mutual illumination varies as a function of light and surface position, in an effort to understand what potential cues are available to the visual system for the recovery of scene layout and colour. Study scenes included corners made from two cards with various hinge angles and different illumination angles as well as a cylinders and other objects. For the corners the scatter plot of the chromaticity profile for a given illumination angle forms a straight line in the CIE chromaticity plane, which shifts systematically toward the “whiter” region of the plane as the illumination angle increases. The slopes of the luminance profiles become steeper and the overall luminance level increases. For the cylinder scene the resulting chromaticity profile is close to a straight line in the chromaticity plane and the luminance profile is non-linear. In summary we find that the colours of the involved objects and lights determine chromaticity profiles of colour gradients, and the luminance profiles convey information about geometry, including illumination angle and/or object shape.