权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Street Lighting Glare: A Study using the measurement of light scatter and fMRI

街道照明眩光：利用光散射测量和功能磁共振成像的研究

基本信息

批准号：
EP/G044538/1
负责人：
Peter Raynham
金额：
$ 71.58万
依托单位：
University College London
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%2FG044538%2F1
关键词：
Street Lighting Glare Study using

项目摘要

Glare has long been recognised as a problem in street lighting. Glare from street lamps and vehicle headlamps can cause discomfort and a reduction in the conspicuity of objects for both motorists and pedestrians. There is some evidence that the current theory may not explain fully the changes in visual performance that relate to the size and the colour of the glare source. Theoretically the effects of scattering of light and aberrations in the eye have a major impact on retinal image quality. Scattering can cause a loss of visual performance due to discomfort, distraction and reduction in contrast sensitivity. In lighting design terms these effects are known as glare. The problem is usually subdivided into discomfort and disability glare.Recently it has become possible to assess scatter in the eye. The new technique involves direct estimates of light scatter in the eye using imaging techniques. It is both rapid and promises to be significantly more accurate than conventional techniques. This technique is critical to the further investigation of disability glare as it gives the researcher the ability to collect together a group of subjects for whom the veiling luminance in any give scene can be calculated precisely.fMRI is another new tool that has recently been developed to the point where it could be useful in the study of glare. Since its introduction, functional magnetic resonance imaging (fMRI) has become a routine method for mapping neural activity in the human brain. Of key importance to this proposal is that previous fMRI studies have shown an increase in the activation levels within the visual cortex (area V1) with increasing stimulus luminance contrast . Areas V1 and V2/V3 have also been shown to respond reliably and strongly to changes in the luminance of uniform surfaces. These cortical areas are regarded as possible candidates for representing the dimension of perceived brightness.The project will address the following points in order to improve our understanding of the issues associated with glare:Light scatter within the eye is a good predictor of the change in visual performance when glare is present. This will be tested by assessing the light scattering properties of the eyes of a number of subjects in the laboratory and then taking the subjects to the open air test centre and giving them a series of tasks representative of those carried out by pedestrians and drivers at night under different levels of glare.Discomfort glare is a function of source size. This will be tested with a series of laboratory experiments to set the comfort/discomfort threshold for various light source colours, sizes and geometries, and by subjective assessment of different lighting schemes in the outdoor environment.Discomfort glare can reduce visual performance. It has been suggested that there is a relationship between discomfort glare and distraction; if this is the case then discomfort glare may disrupt the processing of complex visual tasks. To test this we will run a series of experiments in the laboratory where the subject has to perform a series of visual tasks that are each relatively easy to see but it is hard to do them all simultaneously. By using a series of different glare sources we will assess the impact of discomfort glare. This will be checked by doing facial recognition tasks in the PAMELA laboratory with different levels of discomfort glare carefully set up so that they provide similar levels of disability glare.Discomfort glare is a real phenomenon and can be detected in the brain. To test this idea we will select from our cohort of subjects a group with differing tolerance to glare. We will study the brain activity the group whilst they are given various visual tasks to do with different levels of discomfort glare. From the fMRI scans we hope to find certain patterns of brain activity that are associated with the sensation of glare.

长期以来，眩光一直被认为是街道照明的一个问题。路灯和汽车前灯的眩光会使驾驶者和行人感到不适，并降低物体的可见度。有一些证据表明，目前的理论可能不能完全解释与眩光源的大小和颜色有关的视觉表现的变化。从理论上讲，光散射和眼睛像差的影响对视网膜图像质量有重大影响。由于不舒服、注意力分散和对比敏感度降低，散射会导致视觉性能下降。在照明设计术语中，这些效果被称为眩光。这个问题通常被细分为不适和残疾眩光。最近，评估眼睛中的散射已经成为可能。这项新技术包括使用成像技术直接估计眼睛中的光散射。它既快速，又有望比传统技术准确得多。该技术对于进一步研究残障眩光至关重要，因为它使研究人员能够收集一组受试者，从而可以精确计算任何给定场景下的遮挡亮度。功能磁共振成像是最近发展起来的另一种新工具，它可以用于研究眩光。自问世以来，功能磁共振成像（fMRI）已成为绘制人脑神经活动的常规方法。这一建议的关键是，之前的fMRI研究表明，视觉皮层（V1区）的激活水平随着刺激亮度对比的增加而增加。区域V1和V2/V3也被证明对均匀表面的亮度变化有可靠和强烈的响应。这些皮质区域被认为是代表感知亮度维度的可能候选区域。该项目将解决以下几点，以提高我们对眩光相关问题的理解：当眩光存在时，眼睛内的光散射是视觉性能变化的一个很好的预测指标。这将通过在实验室中评估许多受试者眼睛的光散射特性来进行测试，然后将受试者带到露天测试中心，并给他们一系列具有代表性的任务，这些任务是在夜间不同程度的眩光下由行人和司机进行的。不适眩光是光源大小的函数。这将通过一系列实验室实验来测试，以设置各种光源颜色，尺寸和几何形状的舒适/不适阈值，并通过主观评估室外环境中不同的照明方案。不适的眩光会降低视觉表现。有人认为不适眩光和注意力分散之间存在联系；如果是这样的话，那么不适的眩光可能会干扰复杂视觉任务的处理。为了验证这一点，我们将在实验室里进行一系列实验，实验对象必须完成一系列视觉任务，每个任务都相对容易看到，但很难同时完成。通过使用一系列不同的眩光源，我们将评估不适眩光的影响。这将通过在PAMELA实验室中进行面部识别来验证，在不同程度的不适眩光中仔细设置，以提供相似水平的残疾眩光。不适眩光是一种真实的现象，可以在大脑中检测到。为了验证这一观点，我们将从一组实验对象中选择一组对强光的容忍度不同的人。我们将研究这组人的大脑活动，同时给他们不同程度的不适眩光来完成不同的视觉任务。从功能磁共振成像扫描中，我们希望找到与眩光感觉相关的某些大脑活动模式。