Perception of colour gradients in real and computer-simulated scenes: effects on depth

真实和计算机模拟场景中颜色渐变的感知：对深度的影响

• 批准号: EP/G038708/1
• 负责人: Julie Harris
• 金额: $ 45.8万
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FG038708%2F1
• 关键词: Perception; colour; gradients; real; computer

Can you tell the difference between real filmed footage of an event, and a computer-rendered counterpart? Despite tremendous progress in animation and graphics, the answer is most likely yes. We still have a long way to go in generating high quality realistic rendered worlds, that have a wide variety of applications, from gaming, through medical and industrial simulators, to architect-designed walk-throughs that give us a feel for how a new building could look. Improving the naturalness and realism of such virtual environments is a key challenge for those involved in computer graphics and rendering, particularly when there is a demand for interactive, real-time applications: we want to walk around in that simulated new building, not just view static photograph-like scenes. One of the reasons that our progress is slow, is that the extraordinary visual capabilities of most humans, though apparently effortless, hide a complex web of visual processing that is not yet fully understood. If we do not yet understand what enhances realism for the human visual system, it is not surprising that progress is slow in developing technology to improve the realism of simulations. The aim of this work will be to elucidate some of the basic perceptual processes that underlie how subtle changes in colour and lightness enhance the realism of our perception of a three-dimensional scene. This human behavioural research underpins the development of graphics and rendering technologies that will deliver enhanced realism for virtual environments.One of the reasons why this problem is so hard is that the real world contains very complex patterns of light and colour that somehow translate into our perceptions of whether something is green, light, dark, near or far away. For example, my coffee cup on the table in front of me contains white, bright specular highlights that contribute to it looking glossy. There are also reflections of the stripy table mat on which it sits, yet I know these to be reflections, not part of the pattern on the mug. There is an attached shadow, cast by light from the window, and I know that is not part of my mug. And there are changes in lightness and colour across the surface, yet I see the mug as being a single colour, made from a single material. In this project we will study how humans distinguish between depth, light source, and material properties. For most real scenes, this is a very difficult computational problem because specific local patches that appear, for example, darker than those around them, can have the value they do for a variety of reasons. For example, the side of your grey filing cabinet may have a very different lightness than the front, because it slopes away from you in depth, and is at a different angle with the light source, compared with the front of the cabinet (and it could actually be a different colour). How does the human visual system achieve a coherent perception of a solid, non-deforming world, despite changes in view-point and lighting? This is a huge question in both human and computer vision research, with direct implications for computer graphics and virtual environment development, but one that is still poorly understood. We will start by exploring very simple visual scenes containing isolated objects, and study how colour and luminance information can influence depth perception. This data will be used to create models that predict when the luminance/colour information will be most useful. In other experiments we will use real objects and realistically computer-rendered scenes that preserve the relationship between objects and light source that would occur in the real world. Our work will give us immediate information about basic visual mechanisms of depth and scene perception that directly informs the fields of computer graphics and image processing, giving guidelines for when realistic luminance and colour gradients are required for a rendered scene to look realistic.

您能区分真实拍摄的事件片段和计算机渲染的片段之间的区别吗？尽管动画和图形方面取得了巨大进步，但答案很可能是肯定的。在生成高质量的逼真渲染世界方面，我们还有很长的路要走，这些世界具有广泛的应用范围，从游戏到医疗和工业模拟器，再到建筑师设计的演练，让我们感受新建筑的外观。提高此类虚拟环境的自然度和真实感对于计算机图形和渲染领域的人员来说是一个关键挑战，特别是当需要交互式实时应用程序时：我们希望在模拟的新建筑中走动，而不仅仅是查看静态照片般的场景。我们进步缓慢的原因之一是，大多数人类非凡的视觉能力，虽然表面上毫不费力，但隐藏着一个尚未完全理解的复杂的视觉处理网络。如果我们还不了解增强人类视觉系统真实感的因素，那么提高模拟真实感的技术开发进展缓慢也就不足为奇了。这项工作的目的是阐明一些基本的感知过程，这些过程是颜色和亮度的微妙变化如何增强我们对三维场景感知的真实感的基础。这项人类行为研究支撑了图形和渲染技术的发展，这些技术将为虚拟环境提供增强的真实感。这个问题如此困难的原因之一是现实世界包含非常复杂的光和颜色模式，这些模式以某种方式转化为我们对某物是绿、亮、暗、近还是远的感知。例如，我面前桌子上的咖啡杯包含白色、明亮的镜面高光，使其看起来有光泽。还有它所在的条纹桌垫的倒影，但我知道这些是倒影，而不是杯子上图案的一部分。有一个附加的阴影，是窗户的光投射出来的，我知道那不是我杯子的一部分。表面的亮度和颜色发生了变化，但我认为杯子是单一颜色、由单一材料制成的。在这个项目中，我们将研究人类如何区分深度、光源和材料属性。对于大多数真实场景来说，这是一个非常困难的计算问题，因为例如比周围的斑块更暗的特定局部斑块可能由于各种原因而具有它们所具有的价值。例如，灰色文件柜的侧面可能具有与正面截然不同的亮度，因为与文件柜的正面相比，它在深度上远离您倾斜，并且与光源的角度不同（实际上可能是不同的颜色）。尽管视点和光照发生变化，人类视觉系统如何实现对固体、不变形世界的连贯感知？这是人类和计算机视觉研究中的一个巨大问题，对计算机图形和虚拟环境开发有直接影响，但人们对此仍然知之甚少。我们将从探索包含孤立对象的非常简单的视觉场景开始，并研究颜色和亮度信息如何影响深度感知。该数据将用于创建模型来预测亮度/颜色信息何时最有用。在其他实验中，我们将使用真实的物体和逼真的计算机渲染场景，以保留现实世界中发生的物体和光源之间的关系。我们的工作将为我们提供有关深度和场景感知的基本视觉机制的即时信息，这些信息直接告知计算机图形和图像处理领域，并为何时需要真实的亮度和颜色梯度以使渲染的场景看起来逼真提供指导。

项目成果

Perceptual integration across natural monocular regions.

• DOI: 10.1167/14.3.5
• 发表时间: 2014-03
• 期刊: Journal of vision
• 影响因子: 1.8
• 作者: Katharina M. Zeiner;M. Spitschan;Julie M. Harris

Perception of relative depth interval: systematic biases in perceived depth.

相对深度区间的感知：感知深度的系统偏差。

• DOI: 10.1080/17470218.2011.589520
• 发表时间: 2012
• 期刊: Quarterly journal of experimental psychology (2006)
• 作者: Harris JM

Learning to use illumination gradients as an unambiguous cue to three dimensional shape.

• DOI: 10.1371/journal.pone.0035950
• 发表时间: 2012
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Harding G;Harris JM;Bloj M
• 通讯作者: Bloj M