• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of the Air & Waste Management Association >Which visibility indicators best represent a population's preference for a level of visual air quality?
【24h】

Which visibility indicators best represent a population's preference for a level of visual air quality?

机译：哪些能见度指标最能代表人们对视觉空气质量水平的偏好？

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Several studies have been carried out over the past 20 or so years to assess the level of visual air quality that is judged to be acceptable in urban settings. Groups of individuals were shown slides or computer-projected scenes under a variety of haze conditions and asked to judge whether each image represented acceptable visual air quality. The goal was to assess the level of haziness found to be acceptable for purposes of setting an urban visibility regulatory standard. More recently, similar studies were carried out in Beijing, China, and the more pristine Grand Canyon National Park and Great Gulf Wilderness. The studies clearly showed that when preference ratings were compared to measures of atmospheric haze such as atmospheric extinction, visual range, or deciview (dv), there was not a single indicator that represented acceptable levels of visual air quality for the varied urban or more remote settings. For instance, using a Washington, D.C., setting, 50% of the observers rated the landscape feature as not having acceptable visual air quality at an extinction of 0.19km(-1) (21 km visual range, 29 dv), while the 50% acceptability point for a Denver, Colorado, setting was 0.075km(-1) (52 km visual range, 20 dv) and for the Grand Canyon it was 0.023km(-1) (170 km visual range, 7 dv). Over the past three or four decades, many scene-specific visibility indices have been put forth as potential indicators of visibility levels as perceived by human observers. They include, but are not limited to, color and achromatic contrast of single landscape features, average and equivalent contrast of the entire image, edge detection algorithms such as the Sobel index, and just-noticeable difference or change indexes. This paper explores various scene-specific visual air quality indices and examines their applicability for use in quantifying visibility preference levels and judgments of visual air quality.Implications: Visibility acceptability studies clearly show that visibility become more unacceptable as haze increases. However, there are large variations in the preference levels for different scenes when universal haze indicators, such as atmospheric extinction, are used. This variability is significantly reduced when the sky-landscape contrast of the more distant landscape features in the observed scene is used. Analysis suggest that about 50% of individuals would find the visibility unacceptable if at any time the more distant landscape features nearly disappear, that is, they are at the visual range. This common metric could form the basis for setting an urban visibility standard.
机译：在过去的20年左右的时间里，已经进行了几项研究，以评估被认为在城市环境中可接受的视觉空气质量水平。在不同的雾度条件下，向个人显示幻灯片或计算机投影的场景，并要求他们判断每个图像是否代表可接受的视觉空气质量。目的是评估为建立城市可见性监管标准而可接受的雾度水平。最近，在中国北京以及更为原始的大峡谷国家公园和大海湾荒野进行了类似的研究。这些研究清楚地表明，将偏好等级与大气雾度的度量（例如大气绝灭，视距或视差（dv））进行比较时，没有一个指标可以代表不同城市或更偏远地区的视觉空气质量的可接受水平设置。例如，在华盛顿特区的环境下，50％的观察者将景观特征评为在0.19 km（-1）（21 km视距，29 dv）消光下不具有可接受的视觉空气质量，而50科罗拉多州丹佛市设置的％可接受点为0.075km（-1）（52 km可视范围，20 dv），大峡谷为0.023km（-1）（170 km可视范围，7 dv）。在过去的三到四十年中，已经提出了许多特定于场景的可见性指数，作为人类观察者感知的可见性水平的潜在指标。它们包括但不限于单个景观特征的颜色和消色差对比度，整个图像的平均对比度和等效对比度，边缘检测算法（例如Sobel索引）以及明显的差异或变化索引。本文探讨了各种特定于场景的视觉空气质量指数，并检验了它们在量化可见度偏好水平和视觉空气质量判断中的适用性。含义：可见度可接受性研究清楚地表明，随着雾度的增加，可见度变得越来越不可接受。但是，使用通用的雾度指示器（例如大气消光）时，不同场景的偏好级别会有很大差异。当使用观察场景中较远的景观特征的天空-景观对比度时，这种可变性会大大降低。分析表明，如果在任何时候更远的景观特征几乎消失了，也就是说，它们处于视觉范围内，那么大约50％的人会发现可见度是不可接受的。该通用指标可以构成制定城市知名度标准的基础。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号