Category: Research

Researchers Acquire 3D Images with LED Room Lighting and a Smartphone

Researchers at the University of Strathclyde in the UK have developed a process to use dynamically controlled LEDs for 3D imaging.

In The Optical Society (OSA) journal Optics Express, Researchers at the University of Strathclyde in the UK demonstrated that 3D optical imaging can be performed with a cell phone and LEDs without requiring any complex manual processes to synchronize the camera with the lighting.

“Current video surveillance systems such as the ones used for public transport rely on cameras that provide only 2D information,” said Emma Le Francois, a doctoral student in the research group led by Martin Dawson, Johannes Herrnsdorf and Michael Strain at the University of Strathclyde in the UK. “Our new approach could be used to illuminate different indoor areas to allow better surveillance with 3D images, create a smart work area in a factory, or to give robots a more complete sense of their environment.”

Human vision relies on the brain to reconstruct depth information when we view a scene from two slightly different directions with our two eyes. Depth information can also be acquired using a method called photometric stereo imaging in which one detector, or camera, is combined with illumination that comes from multiple directions. This lighting setup allows images to be recorded with different shadowing, which can then be used to reconstruct a 3D image.

Researchers developed a way to use overhead LED lighting and a smartphone to create 3D images of a small figurine.

Photometric stereo imaging traditionally requires four light sources, such as LEDs, which are deployed symmetrically around the viewing axis of a camera. In the new work, the researchers show that 3D images can also be reconstructed when objects are illuminated from the top down but imaged from the side. This setup allows overhead room lighting to be used for illumination.

“Deploying a smart-illumination system in an indoor area allows any camera in the room to use the light and retrieve the 3D information from the surrounding environment,” said Le Francois. “LEDs are being explored for a variety of different applications, such as optical communication, visible light positioning and imaging. One day the LED smart-lighting system used for lighting an indoor area might be used for all of these applications at the same time.”

In work supported under the UK’s EPSRC Quantic research program, the researchers developed algorithms that modulate each LED in a unique way. This acts like a fingerprint that allows the camera to determine which LED generated which image to facilitate the 3D reconstruction. The new modulation approach also carries its own clock signal so that the image acquisition can be self-synchronized with the LEDs by simply using the camera to passively detect the LED clock signal.

“We wanted to make photometric stereo imaging more easily deployable by removing the link between the light sources and the camera,” said Le Francois. “To our knowledge, we are the first to demonstrate a top-down illumination system with a side image acquisition where the modulation of the light is self-synchronized with the camera.”

In a public area, LEDs could be used for general lighting, visible light communication, and 3D video surveillance. The illustration shows multiple access LiFi — wireless communication technology that uses light to transmit data and position between devices — and visible light positioning in a train station.

To demonstrate this new approach, the researchers used their modulation scheme with a photometric stereo setup based on commercially available LEDs. A simple Arduino board provided the electronic control for the LEDs. Images were captured using the high-speed video mode of a smartphone. They imaged a 48-millimeter-tall figurine that they 3D printed with a matte material to avoid any shiny surfaces that might complicate imaging.

After identifying the best position for the LEDs and the smartphone, the researchers achieved a reconstruction error of just 2.6 millimeters for the figurine when imaged from 42 centimeters away. This error rate shows that the quality of the reconstruction was comparable to that of other photometric stereo imaging approaches. They were also able to reconstruct images of a moving object and showed that the method is not affected by ambient light.

In the current system, the image reconstruction takes a few minutes on a laptop. To make the system practical, the researchers are working to decrease the computational time to just a few seconds by incorporating a deep-learning neural network that would learn to reconstruct the shape of the object from the raw image data.

Comments Off on Researchers Acquire 3D Images with LED Room Lighting and a Smartphone

ELECTRICAL CONTRACTOR: Exit Sign Brightness Study

As lumen depreciation is a significant failure mode with LED lighting, it raises the question whether some older exit signs are still producing sufficient brightness to be visible in smoky conditions. This is the subject of a new study being undertaken by NALMCO in partnership with the Icahn School of Medicine at Mount Sinai in New York, and the topic of an article I wrote about the study for the January issue of ELECTRICAL CONTRACTOR.

As lumen depreciation is a significant failure mode with LED lighting, it raises the question whether some older exit signs are still producing sufficient brightness to be visible in smoky conditions. This is the subject of a new study being undertaken by NALMCO in partnership with the Icahn School of Medicine at Mount Sinai in New York, and the topic of an article I wrote about the study for the January issue of ELECTRICAL CONTRACTOR.

Click here to check it out.

Comments Off on ELECTRICAL CONTRACTOR: Exit Sign Brightness Study

ELECTRICAL CONTRACTOR Publishes 2020 CII Lighting Trends Survey

The electrical contracting community experienced significant economic impacts from the COVID-19 pandemic but is somewhat optimistic about 2021. That is one key finding from the 2020 Commercial/Industrial/Institutional (CII) Lighting Trends Survey, conducted by ELECTRICAL CONTRACTOR in October among the magazine’s Subscriber Research Panel. The survey and article were my contribution to the magazine’s December 2020 issue.

The electrical contracting community experienced significant economic impacts from the COVID-19 pandemic but is somewhat optimistic about 2021. That is one key finding from the 2020 Commercial/Industrial/Institutional (CII) Lighting Trends Survey, conducted by ELECTRICAL CONTRACTOR in October among the magazine’s Subscriber Research Panel. The survey and article were my contribution to the magazine’s December 2020 issue.

Among the key findings:

* A majority of respondents said the COVID-19 pandemic impacted their 2020 business revenues, with the majority of these respondents saying their overall revenues decreased, not just for lighting.

* Overall, respondents are optimistic about 2021, with more saying they expect their revenues related to lighting in all three markets will increase in 2021 than those saying it will decrease. About 30%–40%, however, believe their revenues will remain unchanged.

* A majority of respondents are familiar with major lighting trends, with the greatest familiarity or actual work experience being with wireless lighting controls (73%), color-tunable lighting (63%) and networked lighting controls (61%). Three-fourths of respondents are least familiar with germicidal lighting and the IoT, which is not surprising, because these are relatively new trends. However, upward of three-quarters of respondents who are aware of the technologies are comfortable specifying and installing each of them, with the least comfort for germicidal lighting, IoT and networked lighting controls.

* More than 60% of respondents have discussed lighting quality and color-tunable LED lighting as lighting product features/trends with customers. Nearly half have discussed networked lighting controls. Customers were most interested in lighting quality, followed by color tuning and networked control. However, more than three-quarters were somewhat or very interested in all five technologies.

* The average respondent considers ECs as having a somewhat high degree of influence in selecting lighting equipment for new construction and major renovation CII projects and the highest degree of influence in lighting retrofits.

Check out the article here.

Comments Off on ELECTRICAL CONTRACTOR Publishes 2020 CII Lighting Trends Survey

PNNL Studies Energy Impacts of Circadian Lighting

The Pacific Northwest National Laboratory (PNNL) recently published a new report analyzing the energy impact of lighting designs that satisfy three prominent circadian lighting guidelines. The researchers discovered a potentially significant increase in light levels and associated energy consumption.

The Pacific Northwest National Laboratory (PNNL) recently published a new report analyzing the energy impact of lighting designs that satisfy three prominent circadian lighting guidelines. The researchers discovered a potentially significant increase in light levels and associated energy consumption.

An open office and a classroom were modeled, with the luminaire lumen output, spectral power distribution, surface reflectance distribution, and desk orientation varying between the simulations in order to explore the magnitude of the different parameters. The simulations aimed to comply with the design guidelines WELL v2 Q2 2019, UL Design Guideline 24480, and Collaborative for High Performance Schools Core Criteria 3.0. A total of 45 unique simulation conditions were evaluated in the two models.

The researchers determined that meeting current IES light level recommendations did not satisfy existing equivalent melanopic lux and circadian stimulus values for any of the office and classroom circadian lighting recommendations. They found significant increases in indoor light levels and corresponding lighting energy use; in some cases, meeting the circadian metric recommendations required an average illuminance that was more than double the IES recommendations, which may negatively affect lighting quality and increase energy use. Based on the results, the study estimates that lighting energy use may increase by 10% to 100% because of the higher luminaire light levels used to meet the circadian lighting design recommendations listed in current building standards.

Said PNNL:

Further research may show more-efficient ways to meet design recommendations through varied light distribution or optimized spectral characteristics, as well as advanced control systems. Until circadian lighting design metrics and effective delivery of light stimulus are better understood in realistic settings with recognizable health and well-being benefits, the tradeoffs between design recommendations and energy efficiency goals cannot be fully expressed.

Click here to check out the report.

Comments Off on PNNL Studies Energy Impacts of Circadian Lighting

Market Report: Global LED Market to Reach $82 Billion by 2026

Frost & Sullivan’s recent analysis, 2020 Annual Update of Global LED Lighting Market, finds that the increasing demand for energy-efficient lighting, the rising number of smart city projects and overall infrastructure development are driving the LED lighting market across the globe.

Frost & Sullivan’s recent analysis, 2020 Annual Update of Global LED Lighting Market, finds that the increasing demand for energy-efficient lighting, the rising number of smart city projects and overall infrastructure development are driving the LED lighting market across the globe.

The market is estimated to reach $82 billion by 2026 from $67.7 billion in 2019, at a compound annual growth rate (CAGR) of 2.8%.

However, with the COVID-19 pandemic, the industry is likely to experience varied impacts across regions due to discrepancies in containment measures and lockdown implementation. Even with the partial ease in lockdowns and a resumption of manufacturing, the market will need a couple of years to recover and reach the same level as before the crisis.

“Smart buildings will accelerate the adoption of smart lighting more than any other segment. The revitalization of cities will also provide the much-needed impetus for the installation of smart lighting,” said Dennis Marcell Victor, Energy & Environment Research Analyst at Frost & Sullivan. “Government rebates, savings on disposal costs, improved performance of workers, and limitless Internet of Things (IoT) applications for LED lighting present a good business case for LEDs to be adopted across applications.”

Victor added: “Lighting-as-a-Service (LaaS) will see higher adoption and usher in a new business model while driving other applications such as connected lighting and facility management. It is expected to reduce the capital expenditure of the consumer, with service providers bearing upfront costs.

Additionally, from a regional perspective, Asia-Pacific (APAC) continues to be the key growth area, drawing $35.4 billion in revenues by 2026, with India and China contributing the maximum revenue. Similarly, after APAC, Europe and North America will contribute significantly to the market due to developments in advanced lighting applications related to the healthcare, industrial, office, and hospitality verticals in both regions. Each respectively witnessing growth of 4.0% and 4.1% throughout the forecast period. Latin America will experience the highest growth over the forecast period at 5.1% because of its focus on office and street lighting as part of smart city solutions.

The increasing adoption of LED lighting across healthcare, automotive, industrial, and office segments presents immense growth prospects for market participants, including:

  • LaaS business model: Companies need to take a pragmatic approach toward monetizing LaaS to improve revenue.
  • Digital LED lights for automobiles: Autonomous vehicles need to implement digital LED lights technology to enhance safety features.
  • Circular economy for LED lighting: Circular economy measures should start from the design phase. Designing modular, upgradeable, and reusable products will help reduce waste from used LED light sources.
  • UVC-LEDs for disinfection: UV-C lights can be used to disinfect workplaces, healthcare centers, and public transport. Proper guidelines should be outlined for handling UV-C lights for widespread usage.

Click here to learn more about the report.

Comments Off on Market Report: Global LED Market to Reach $82 Billion by 2026

DOE Study Examines Age-Related Changes in LED Device Efficiency and Optical Performance

The U.S. Department of Energy (DOE) recently released a study investigating age-related changes in LED device efficiency and optical performance.

The U.S. Department of Energy (DOE) recently released a study investigating age-related changes in LED device efficiency and optical performance.

Lighting application efficiency (LAE)—the efficient delivery of light from the light source to the lighted task—is a useful way to identify and improve the energy productivity of LED technologies. Because of their high reliability, light source efficiency, and spectral tuning capabilities, LED lighting products are expected to exceed their conventional counterparts in LAE. The new study aimed to increase understanding of the tradeoffs involved in optimizing the different elements of LAE: light source efficiency, optical delivery efficiency, spectral efficiency, and intensity effectiveness.

Conducted by RTI International, the study focused on products with modified spectral output, as the method of spectral modification has a significant impact on the efficiencies in question. The report summarizes the findings from up to 8,000 hours of accelerated stress testing (AST) on lamp, LED light-engine, and downlight devices. The AST included high-temperature and wet high-temperature operation.

The findings show that the optimization of spectral efficiency can come at the cost of initial light source efficiency. Furthermore, the introduction of violet LEDs can promote long-term optical delivery efficiency degradation, and the introduction of optical filters or new phosphors can lead to unwanted spectral efficiency changes, because the ratio of phosphor emitters changes with aging.

Other key findings:

• Chromaticity maintenance of the products was generally good, with parametric failure only occurring for one product at one AST condition.
• Longer test times are needed to fully understand the luminous flux maintenance, luminous efficacy changes, and chromaticity shifts for some of the products.
• The study identified a common failure location in six-inch downlights.

The study results provide valuable information about changes to the light source, spectral, and optical delivery efficiencies as the devices age. This information can be used to improve future SSL designs.

Click here to see the report.

Comments Off on DOE Study Examines Age-Related Changes in LED Device Efficiency and Optical Performance

New Lighting System Helps Deer Avoid Vehicles at Night

Researchers with the U.S. Department of Agriculture’s (USDA) Wildlife Services (WS) program recently applied for a patent (U.S. Patent Application No. 16/668,253) for a new vehicle-based lighting system to prevent deer-vehicle collisions during low-light conditions.

Researchers with the U.S. Department of Agriculture’s (USDA) Wildlife Services (WS) program recently applied for a patent (U.S. Patent Application No. 16/668,253) for a new vehicle-based lighting system to prevent deer-vehicle collisions during low-light conditions.

Through a series of experiments with free-roaming white-tailed deer, researchers at the WS program’s National Wildlife Research Center (NWRC) found the use of a rear-facing LED light bar‒which illuminates a larger portion of the vehicle’s front surface than standard headlights alone‒resulted in fewer dangerous deer-vehicle interactions.

The likelihood of dangerous interactions decreased from 35% to only 10% of vehicle approaches when using a rear-facing light bar plus headlights versus just headlights alone. The reduction in dangerous interactions appeared to be driven by fewer instances of immobility or “freezing” behavior by deer when the light bar was used. The study “Frontal vehicle illumination via rear-facing lighting reduces potential for collisions with white-tailed deer” is highlighted in the latest issue of the journal Ecosphere.

“This new lighting system takes advantage of a deer’s predator avoidance behavior (also known as flight behavior),” states lead author and former NWRC researcher Dr. Travis DeVault who currently serves as the associate director of the University of Georgia’s Savannah River Ecology Laboratory. “We predicted that light reflected from the front surface of the vehicle would provide a more reliable looming image to deer, thus encouraging the deer to move out of the path of the approaching vehicle.”

When an object “looms,” it becomes increasingly larger to the perceiving animal, helping the animal realize that the object is an approaching object versus one that is stationary.

In the United States and Canada, deer cause the majority of animal-related injurious and deadly road collisions. A vehicle-based system, such as the rear-facing LED light bar, advances efforts to reduce wildlife deaths and increase driver safety on roads.

The patent-pending technology can be incorporated as an after-market device, like a brush guard or bumper, or can be embedded in the vehicle as part of the manufacturing process.

USDA is currently seeking a licensing partner to build and market the technology. For more information, please contact NWRC’s Technology Transfer Program Manager john.d.eisemann@usda.gov.

1 Comment on New Lighting System Helps Deer Avoid Vehicles at Night

Researchers Convert Light to Sound to Detect Concealed Nanostructures

Researchers at the Advanced Research Center for Nanolithography (ARCNL) have produced a method of using light to induce high-frequency sound waves, which in turn are used to reveal the internal structure of opaque materials in very small structures such as semiconductors.

Researchers at the Advanced Research Center for Nanolithography (ARCNL) have produced a method of using light to induce high-frequency sound waves, which in turn are used to reveal the internal structure of opaque materials in very small structures such as semiconductors.

Many opaque materials transmit sound waves, enabling echoscope inspection whereby high-frequency sound waves are passed through a material to visualize what’s inside it. This method is limited, however, as the finer the visualization, the higher the frequency required.

The ARCNL researchers applied short pulses of light from a laser to induce sound waves at a high enough frequency that visualization of nanostructures was enabled.

These findings could find applications in the semiconductor manufacturing industry, such as wafer alignment, which uses grating lines to ensure properly aligned layering of nano-structures on wafers.

PHYS.org has the story here.

Comments Off on Researchers Convert Light to Sound to Detect Concealed Nanostructures

A New Spy Tool: Lamps

Researchers from Israeli’s Ben-Gurion University of the Negev and the Weizmann Institute of Science have discovered a new technique for long-distance eavesdropping on voice conversations by observing tiny vibrations these sounds make on the glass surface of a visible lamp.

Researchers from Israeli’s Ben-Gurion University of the Negev and the Weizmann Institute of Science have discovered a new technique for long-distance eavesdropping on voice conversations by observing tiny vibrations these sounds make on the glass surface of a visible lamp.

They say it allows anyone with a laptop and less than a thousand dollars of equipment—just a telescope and a $400 electro-optical sensor—to listen in on any sounds in a room that’s hundreds of feet away in real-time, simply by observing the minuscule vibrations those sounds create on the glass surface of a light bulb inside. By measuring the tiny changes in light output from the bulb that those vibrations cause, the researchers show that a spy can pick up sound clearly enough to discern the contents of conversations or even recognize a piece of music.

ARCS TECHNICA has the story here.

Comments Off on A New Spy Tool: Lamps

Signify Demonstrates UV-C Effective Against SARS-CoV-2

The COVID-19 pandemic has spurred fresh interest in UV-C as a way to disinfect objects and surfaces. Signify and the National Emerging Infectious Diseases Laboratories (NEIDL) at Boston University conducted research that demonstrates effectiveness of the company’s UV-C light sources on the inactivation of SARS-CoV-2, the virus that causes COVID-19.

The COVID-19 pandemic has spurred fresh interest in UV-C as a way to disinfect objects and surfaces. Signify and the National Emerging Infectious Diseases Laboratories (NEIDL) at Boston University conducted research that demonstrates effectiveness of the company’s UV-C light sources on the inactivation of SARS-CoV-2, the virus that causes COVID-19.

Since the start of the SARS CoV-2 pandemic, Dr. Anthony Griffiths, Associate Professor of Microbiology at Boston University School of Medicine and his team have been working on developing tools to support scientific advancement in this field. During their research, they treated inoculated material with different doses of UV-C radiation and assessed the inactivation capacity under various conditions. The team applied a dose of 5mJ/cm2, resulting in a reduction of the SARS-CoV-2 virus of 99% in 6 seconds.

Based on the data, it was determined that a dose of 22mJ/cm2 will result in a reduction of 99.9999% in 25 seconds.

“Our test results show that above a specific dose of UV-C radiation, viruses were completely inactivated; in a matter of seconds we could no longer detect any virus,” said Dr. Anthony Griffiths, Associate Professor of Microbiology at Boston University School of Medicine. “We’re very excited about these findings and hope that this will accelerate the development of products that can help limit the spread of COVID-19.”

“Given the potential of the technology to aid the fight against the coronavirus, Signify will not keep the technology for its exclusive use but make it available to other lighting companies,” said Eric Rondolat, CEO of Signify. “To service the growing need for disinfection we will increase our production capacity multifold in the coming months.”

Because direct UV-C exposure to humans can increase cancer risk, and even short exposures can produce burns on unprotected skin and retinal damage, UV-C energy is used to directly disinfect surfaces in unoccupied spaces.

4 Comments on Signify Demonstrates UV-C Effective Against SARS-CoV-2

Type on the field below and hit Enter/Return to search