|By Business Wire||
|July 18, 2014 10:49 AM EDT||
Long hours of nighttime driving can cause eyestrain because while our vision adapts to the surrounding darkness, the sudden stabs of brightness from streetlamps can be irritating, distracting and even painful. Even as LED technology has transformed the lighting industry, bringing the promise of more energy-efficient road illumination, some fear that the new lights could cause even more troublesome, unsafe glare.
To investigate the effect of LED streetlights on the discomfort glare perceived by drivers, researchers from China and the Netherlands devised a laboratory set-up to mimic visual conditions on the road. The volunteers were asked to rate their level of discomfort with the glare on a standard deBoer 9-point rating scale, ranging from unnoticeable to unbearable. This photo shows a road with LED streetlamp glare where the researchers validated their laboratory findings. Credit: Yandan Lin.
A team of researchers from China and the Netherlands has developed a way to evaluate the human impact of uncomfortable glare caused by LED road lights. They created a model that can predict the level of discomfort experienced by drivers under various lighting conditions. The team today reported their findings, which could guide streetlight placement and design, in The Optical Society’s (OSA) open-access journal Optics Express.
“With the development of the LED industry, there is no doubt that more and more LED lights will be used for road lighting,” said Yandan Lin, an associate professor and director of the Vision and Color Research Laboratory at Fudan University in Shanghai, China. “We believe that the lighting industry has an urgent need to update the ways to characterize discomfort glare caused by LED road lights.”
Traditional ways of predicting how much a person will want to look away from a bright light, characterized by a term called discomfort glare, are based on the nature of conventional light sources and may not be appropriate for LED streetlights, Lin noted. For example, LEDs are designed to emit the same amount of light as conventional bulbs from a smaller area, which could possibly increase the discomfort glare. In addition, white LEDs typically have more energy in the blue part of spectrum, which can also cause more glare because blue light is perceived brighter by the human eye under the same light levels, based on past studies.
To investigate the effect of LED streetlights on the discomfort glare perceived by drivers, the team devised a laboratory set-up to mimic visual conditions on the road. The researchers painted the floors and walls of a room completely black, and then positioned a collection of light sources around the room to simulate the illumination from an LED streetlamp as it would appear to a driver on a dark road. The researchers adjusted the light sources to create 72 different lighting conditions, and volunteer observers were asked to rate their level of discomfort glare under each condition on a standard deBoer 9-point rating scale, ranging from “unnoticeable” to “unbearable.”
The team was guided in the selection of test lighting conditions by previous work done on discomfort glare. “Although the characterization of discomfort glare for conventional light sources may not be applied to LEDs, the possible factors affecting discomfort glare may remain the same,” Lin explained.
Lin and her colleagues systematically modified four lighting parameters in their experiments: the luminance (i.e., the luminous intensity of light per given area) of the LED lights, the background luminance, the apparent size of the LED lights from the perspective of the observers (measured by a parameter called solid angle), and the angle between the LEDs and the line of sight of the observers.
Based on the results, the team developed a model that related the four parameters mentioned above to the level of discomfort glare experienced by an observer. They validated the model with two additional experiments – one carried out in the lab and one on the real roads.
The researchers found that the interaction between the LED luminance and the solid angle, which can be characterized by the amount of light hitting an observer’s eyes (known as vertical illuminance) was the most significant factor affecting discomfort glare. To minimize discomfort, they recommend minimizing both the amount of light hitting at the eyes and the luminance contrast between the streetlights and the background, which can be accomplished through good optical design of the LED light unit and careful placement of each streetlight.
While more follow-up work would be needed before the team’s results could guide industry standards, the researchers hope their model could still be put to immediate use by design and construction firms working on LED streetlight replacements and installations.
Going forward, the team plans an interdisciplinary investigation of the physiological changes caused by glare, which could allow the researchers to ditch the 9-point rating scale in favor of more concrete measurements of discomfort such as eye movement and pupil size.
“Glare has a strong effect on the normal visual function, causing a serious threat to safety. And the accumulative effect of glare also threatens the physiological health of the human body,” Lin said. “So it’s very important to reduce the glare on roadways.”
Paper: “A model predicting discomfort glare caused by LED road lights,” Y. Lin et al., Optics Express, Vol. 22, Issue 15, pp. 18056-18071 (2014).
EDITOR’S NOTE: An image of LED streetlight glare is available to members of the media upon request. Contact Angela Stark, [email protected].
About Optics Express
Optics Express reports on new developments in all fields of optical science and technology every two weeks. The journal provides rapid publication of original, peer-reviewed papers. It is published by The Optical Society and edited by Andrew M. Weiner of Purdue University. Optics Express is an open-access journal and is available at no cost to readers online at www.OpticsInfoBase.org/OE.
Founded in 1916, The Optical Society (OSA) is the leading professional society for scientists, engineers, students and business leaders who fuel discoveries, shape real-world applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership programs, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of professionals in optics and photonics. For more information, visit www.osa.org.
The enterprise is being consumerized, and the consumer is being enterprised. Moore's Law does not matter anymore, the future belongs to business virtualization powered by invisible service architecture, powered by hyperscale and hyperconvergence, and facilitated by vertical streaming and horizontal scaling and consolidation. Both buyers and sellers want instant results, and from paperwork to paperless to mindless is the ultimate goal for any seamless transaction. The sweetest sweet spot in innov...
Oct. 10, 2015 08:00 AM EDT Reads: 236
SYS-CON Events announced today that Key Information Systems, Inc. (KeyInfo), a leading cloud and infrastructure provider offering integrated solutions to enterprises, will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Key Information Systems is a leading regional systems integrator with world-class compute, storage and networking solutions and professional services for the most advanced softwa...
Oct. 10, 2015 07:30 AM EDT Reads: 440
"Matrix is an ambitious open standard and implementation that's set up to break down the fragmentation problems that exist in IP messaging and VoIP communication," explained John Woolf, Technical Evangelist at Matrix, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Oct. 10, 2015 07:00 AM EDT Reads: 5,935
The modern software development landscape consists of best practices and tools that allow teams to deliver software in a near-continuous manner. By adopting a culture of automation, measurement and sharing, the time to ship code has been greatly reduced, allowing for shorter release cycles and quicker feedback from customers and users. Still, with all of these tools and methods, how can teams stay on top of what is taking place across their infrastructure and codebase? Hopping between services a...
Oct. 10, 2015 06:00 AM EDT Reads: 527
Containers are changing the security landscape for software development and deployment. As with any security solutions, security approaches that work for developers, operations personnel and security professionals is a requirement. In his session at @DevOpsSummit, Kevin Gilpin, CTO and Co-Founder of Conjur, will discuss various security considerations for container-based infrastructure and related DevOps workflows.
Oct. 10, 2015 06:00 AM EDT Reads: 271
WebRTC has had a real tough three or four years, and so have those working with it. Only a few short years ago, the development world were excited about WebRTC and proclaiming how awesome it was. You might have played with the technology a couple of years ago, only to find the extra infrastructure requirements were painful to implement and poorly documented. This probably left a bitter taste in your mouth, especially when things went wrong.
Oct. 10, 2015 06:00 AM EDT Reads: 817
DevOps and Continuous Delivery software provider XebiaLabs has announced it has been selected to join the Amazon Web Services (AWS) DevOps Competency partner program. The program is designed to highlight software vendors like XebiaLabs who have demonstrated technical expertise and proven customer success in DevOps and specialized solution areas like Continuous Delivery. DevOps Competency Partners provide solutions to, or have deep experience working with AWS users and other businesses to help t...
Oct. 10, 2015 06:00 AM EDT Reads: 244
Enterprises can achieve rigorous IT security as well as improved DevOps practices and Cloud economics by taking a new, cloud-native approach to application delivery. Because the attack surface for cloud applications is dramatically different than for highly controlled data centers, a disciplined and multi-layered approach that spans all of your processes, staff, vendors and technologies is required. This may sound expensive and time consuming to achieve as you plan how to move selected applicati...
Oct. 10, 2015 05:00 AM EDT Reads: 733
The broad selection of hardware, the rapid evolution of operating systems and the time-to-market for mobile apps has been so rapid that new challenges for developers and engineers arise every day. Security, testing, hosting, and other metrics have to be considered through the process. In his session at Big Data Expo, Walter Maguire, Chief Field Technologist, HP Big Data Group, at Hewlett-Packard, will discuss the challenges faced by developers and a composite Big Data applications builder, foc...
Oct. 10, 2015 04:00 AM EDT Reads: 520
Nowadays, a large number of sensors and devices are connected to the network. Leading-edge IoT technologies integrate various types of sensor data to create a new value for several business decision scenarios. The transparent cloud is a model of a new IoT emergence service platform. Many service providers store and access various types of sensor data in order to create and find out new business values by integrating such data.
Oct. 10, 2015 04:00 AM EDT Reads: 603
Data loss happens, even in the cloud. In fact, if your company has adopted a cloud application in the past three years, data loss has probably happened, whether you know it or not. In his session at 17th Cloud Expo, Bryan Forrester, Senior Vice President of Sales at eFolder, will present how common and costly cloud application data loss is and what measures you can take to protect your organization from data loss.
Oct. 10, 2015 03:00 AM EDT Reads: 593
The cloud has reached mainstream IT. Those 18.7 million data centers out there (server closets to corporate data centers to colocation deployments) are moving to the cloud. In his session at 17th Cloud Expo, Achim Weiss, CEO & co-founder of ProfitBricks, will share how two companies – one in the U.S. and one in Germany – are achieving their goals with cloud infrastructure. More than a case study, he will share the details of how they prioritized their cloud computing infrastructure deployments ...
Oct. 10, 2015 03:00 AM EDT Reads: 755
There are so many tools and techniques for data analytics that even for a data scientist the choices, possible systems, and even the types of data can be daunting. In his session at @ThingsExpo, Chris Harrold, Global CTO for Big Data Solutions for EMC Corporation, will show how to perform a simple, but meaningful analysis of social sentiment data using freely available tools that take only minutes to download and install. Participants will get the download information, scripts, and complete en...
Oct. 10, 2015 03:00 AM EDT Reads: 336
WebRTC: together these advances have created a perfect storm of technologies that are disrupting and transforming classic communications models and ecosystems. In his session at WebRTC Summit, Cary Bran, VP of Innovation and New Ventures at Plantronics and PLT Labs, will provide an overview of this technological shift, including associated business and consumer communications impacts, and opportunities it may enable, complement or entirely transform.
Oct. 10, 2015 02:15 AM EDT Reads: 772
SYS-CON Events announced today that Dyn, the worldwide leader in Internet Performance, will exhibit at SYS-CON's 17th International Cloud Expo®, which will take place on November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Dyn is a cloud-based Internet Performance company. Dyn helps companies monitor, control, and optimize online infrastructure for an exceptional end-user experience. Through a world-class network and unrivaled, objective intelligence into Internet condit...
Oct. 10, 2015 02:00 AM EDT Reads: 661