Light-emitting Diode Illumination Research Articles

Spectral Image Processing for Museum Lighting Using CIE LED Illuminants.

This work presents a spectral color-imaging procedure for the detailed colorimetric study of real artworks under arbitrary illuminants. The results demonstrate this approach to be a powerful tool for art and heritage professionals when deciding which illumination to use in museums, or which conservation or restoration techniques best maintain the color appearance of the original piece under any illuminant. Spectral imaging technology overcomes the limitations of common area-based point-measurement devices such as spectrophotometers, allowing a local study either pixelwise or by selected areas. To our knowledge, this is the first study available that uses the proposed CIE (Commission Internationale de l’Éclairage) light-emitting diode (LED) illuminants in the context of art and heritage science, comparing them with the three main CIE illuminants A, D50, and D65. For this, the corresponding colors under D65 have been calculated using a chromatic adaptation transform analogous to the one in CIECAM02. For the sample studied, the CIE LED illuminants with the lowest average CIEDE2000 color differences from the standard CIE illuminants are LED-V1 for A and LED-V2 for D50 and D65, with 1.23, 1.07, and 1.57 units, respectively. The work studied is a Moorish epigraphic frieze of plasterwork with a tiled skirting from the Nasrid period (12th–15th centuries) exhibited in the Museum of the Alhambra (Granada, Spain).

Combined artificial high-silicate medium and LED illumination promote carotenoid accumulation in the marine diatom Phaeodactylum tricornutum

BackgroundDiatoms, which can accumulate large amounts of carotenoids, are a major group of microalgae and the dominant primary producer in marine environments. Phaeodactylum tricornutum, a model diatom species, acquires little silicon for its growth although silicon is known to contribute to gene regulation and play an important role in diatom intracellular metabolism. In this study, we explored the effects of artificial high-silicate medium (i.e. 3.0 mM sodium metasilicate) and LED illumination conditions on the growth rate and pigment accumulation in P. tricornutum, which is the only known species so far that can grow without silicate. It’s well known that light-emitting diodes (LEDs) as novel illuminants are emerging to be superior monochromatic light sources for algal cultivation with defined and efficient red and blue lights.ResultsFirstly, we cultivated P. tricornutum in a synthetic medium supplemented with either 0.3 mM or 3.0 mM silicate. The morphology and size of diatom cells were examined: the proportion of the oval and triradiate cells decreased while the fusiform cells increased with more silicate addition in high-silicate medium; the average length of fusiform cells also slightly changed from 14.33 µm in 0.3 mM silicate medium to 12.20 µm in 3.0 mM silicate medium. Then we cultivated P. tricornutum under various intensities of red light in combination with the two different levels of silicate in the medium. Higher biomass productivity also achieved in 3.0 mM silicate medium than in 0.3 mM silicate medium under red LED light irradiation at 128 μmol/m2/s or higher light intensity. Increasing silicate reversed the down-regulation of fucoxanthin and chlorophyll a under high red-light illumination (i.e. 255 μmol/m2/s). When doubling the light intensity, fucoxanthin content decreased under red light but increased under combined red and blue (50:50) lights while chlorophyll a content reduced under both conditions. Fucoxanthin accumulation and biomass productivity increased with enhanced red and blue (50:50) lights.ConclusionHigh-silicate medium and blue light increased biomass and fucoxanthin production in P. tricornutum under high light conditions and this strategy may be beneficial for large-scale production of fucoxanthin in diatoms.

1 cm2 Organic Photovoltaic Cells for Indoor Application with over 20% Efficiency.

Organic photovoltaic (OPV) technologies have the advantages of fabricating larger-area and light-weight solar panels on flexible substrates by low-cost roll-to-toll production. Recently, OPV cells have achieved many significant advances with power conversion efficiency (PCE) increasing rapidly. However, large-scale solar farms using OPV modules still face great challenges, such as device stability. Herein, the applications of OPV cells in indoor light environments are studied. Via optimizing the active layers to have a good match with the indoor light source, 1 cm2 OPV cells are fabricated and a top PCE of 22% under 1000 lux light-emitting diode (2700 K) illumination is demonstrated. In this work, the light intensities are measured carefully. Incorporated with the external quantum efficiency and photon flux spectrum, the integral current densities of the cells are calculated to confirm the reliability of the photovoltaic measurement. In addition, the devices show much better stability under continuous indoor light illumination. The results suggest that designing wide-bandgap active materials to meet the requirements for the indoor OPV cells has a great potential in achieving higher photovoltaic performance.

Molecular analysis of genes related to phenylpropanoid and ascorbate biosynthesis in salt and UV-B treated pak choi grown under LEDs

In this study, we measured the expression of genes related to the phenylpropanoid pathway and ascorbate oxidation by qRT-PCR to explore the mechanism of nutraceutical compounds enhancement in pak choi during stress treatments. The expression of most phenylpropanoid biosynthesis related genes (PAL, C4H, CHS, CHI, F3H1, DFR, and ANS1) was up-regulated in plants treated with NaCl, solar salt, and UV-B radiation, compared with the untreated controls under both white light and light emitting diode illumination. Moreover, CHS and ANS1 were expressed at levels 15 and 95 times higher than the untreated control. The expression of the ascorbate oxidation related gene tAPX was also up-regulated in the NaCl and UV-B treated samples compared with the control under both light conditions. By comparison, the expression of APX1 was down-regulated during the stress treatment under both light conditions. Total chlorophyll and total carotenoid contents were unaffected by the stress treatments, and there was no significant difference in the maximum quantum yield (Fv/Fm) between the stress treatments and the untreated controls. These results suggest that the expression of genes involved in phenylpropanoid biosynthesis and ascorbate oxidation correlates with the previously reported enhanced production of phenolic compounds in pak choi plants subjected to stress treatments.

Antibacterial effect and mechanisms of action of 460–470 nm light-emitting diode against Listeria monocytogenes and Pseudomonas fluorescens on the surface of packaged sliced cheese

The aim of this study was to investigate the antibacterial effect of 460–470 nm light-emitting diode (LED460–470nm) illumination against pathogens and spoilage bacteria on the surface of agar media and packaged sliced cheese. LED460–470nm illumination highly inhibited the growth of Listeria monocytogenes and Pseudomonas fluorescens on agar media covered with oriented polypropylene (OPP) film (thickness, 0.03 mm). When sliced cheeses inoculated with L. monocytogenes or P. fluorescens and packaged with OPP film were illuminated by an LED460–470 nm at 4 or 25 °C, reduction levels of L. monocytogenes and P. fluorescens on packaged slice cheese were higher at 4 °C than at 25 °C. There were no significant differences in color between non-illuminated and illuminated sliced cheese after storage for 7 d at 4 °C. LED460–470 nm illumination at 4 °C for 4 d caused cellular injury of L. monocytogenes and P. fluorescens related to RNA, protein, and peptidoglycan metabolism, and a disruption of the cell membrane and loss of cytoplasmic components were observed from TEM results. These results suggest that LED460–470 nm illumination, in combination with refrigeration temperatures, may be applied to extend the shelf-life of packaged slice cheese and minimize the risk of foodborne disease, without causing color deterioration.

Effects of 405-nm LED Treatment on the Resistance of Listeria monocytogenes to Subsequent Environmental Stresses.

Listeria monocytogenes can persist under a wide range of stress conditions, contributing to its ubiquitous distribution and unique pathogenic traits. Light from light-emitting diodes (LEDs) has recently been shown to inactivate various pathogens. Thus, the aim of the present study was to evaluate the effects of light treatment using a 405-nm LED on the subsequent resistance of L. monocytogenes to environmental stresses, including oxidative stress, ultraviolet (UV) irradiation, low temperature, osmotic pressure, simulated gastric fluid (SGF), and bile salts. Following 405-nm LED illumination at 4°C for 150 min, the survival of L. monocytogenes was examined after exposure to oxidative stress (0.04% H2O2), UV irradiation (253.7 nm), low temperature (4°C), osmotic pressure (10, 15, or 20% NaCl), SGF (pH 2.5), or bile salts (2%). The mechanisms responsible for changes in stress tolerance were identified by assessing the transcriptional responses and membrane integrity of L. monocytogenes. The 405-nm LED treatment reduced the resistance of L. monocytogenes to all the stresses tested. Reverse transcription quantitative real-time polymerase chain reaction analysis indicated that the transcription of multiple genes associated with stress resistance, including betL, gbuA, oppA, fri, bsh, and arcA, was reduced by 405-nm LED. Confocal laser scanning microscopy revealed that 405-nm LED treatment disrupted the integrity of the L. monocytogenes cell membrane compared with untreated bacteria. Therefore, 405-nm LED illumination appears to reduce the resistance of L. monocytogenes to various stress conditions. These findings suggest that 405-nm LED treatment could be used to effectively prevent and/or control with L. monocytogenes contamination along the entire food-processing chain, from production to consumption.

Thin-film light-addressable potentiometric sensor with SnOx as a photosensitive semiconductor

In this study, a tin-based oxide (SnOx) semiconductor layer on a commercial indium tin oxide (ITO)/glass substrate was investigated for the first time for use as the active layer of a light-addressable potentiometric sensor (LAPS). The photoabsorption of SnOx layers sputtered using varying Ar/O2 gas flow ratios was characterized by means of the ultraviolet–visible spectroscopy (UV–Vis); the photo/electric response of a LAPS directly covered with an NbOx sensing membrane was evaluated under modulated ultraviolet illumination. In situ substrate heating at 250 °C during sputtering and post-deposition rapid thermal annealing (RTA) with temperatures of 400 and 450 °C in a N2 environment were applied to study sample behavior. Based on X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results, the fabricated SnO2 layer can be transformed into a polycrystalline SnO2 phase in the bulk with a surface SnO layer by thermal budget. A high photocurrent and an acceptable pH sensitivity of 1.29 μA and 57.6 mV/pH, respectively, are obtained under UV light-emitting diode (LED) illumination for a LAPS built using a SnOx layer sputtered with a flow ratio of Ar/O2 = 46/4 with substrate heating at 250 °C. The stability and lifetime performance of the SnOx LAPS needs to be improved by further process optimization, especially in terms of developing a crack-free SnOx process and increasing sensing membrane coverage. The experimental results show the potential of SnOx for use as the active layer in a LAPS.

Light-emitting diode therapy protects against ventricular arrhythmias by neuro-immune modulation in myocardial ischemia and reperfusion rat model

BackgroundSympathetic overactivation and inflammation are two major mediators to post-myocardial ischemia-reperfusion (I/R)-induced ventricular arrhythmia (VA). The vicious cycle between microglia and sympathetic activation plays an important role in sympathetic hyperactivity related to cardiovascular diseases. Recently, studies have shown that microglial activation might be attenuated by light-emitting diode (LED) therapy. Therefore, we hypothesized that LED therapy might protect against myocardial I/R-induced VAs by attenuating microglial and sympathetic activation.MethodsThirty-six male anesthetized rats were randomized into four groups: control group (n = 6), LED group (n = 6), I/R group (n = 12), and LED+I/R group (n = 12). I/R was generated by left anterior descending artery occlusion for 30 min followed by 3 h reperfusion. ECG and left stellate ganglion (LSG) neural activity were recorded continuously. After 3 h reperfusion, a programmed stimulation protocol was conducted to test the inducibility of VA. Furthermore, we extracted the brain tissue to examine the microglial activation, and the peri-ischemic myocardium to examine the expression of NGF and inflammatory cytokines (IL-1β, IL-18, IL-6, and TNF-α).ResultsAs compared to the I/R group, LED illumination significantly inhibited the LSG neural activity (P < 0.01) and reduced the inducibility of VAs (arrhythmia score 4.417 ± 0.358 vs. 3 ± 0.3257, P < 0.01) in the LED+I/R group. Furthermore, LED significantly attenuated microglial activation and downregulated the expression of inflammatory cytokines and NGF in the peri-infarct myocardium.ConclusionsLED therapy may protect against myocardial I/R-induced VAs by central and peripheral neuro-immune regulation.

Retinal damage after exposure to white light emitting diode lights at different intensities in Sprague-Dawley rats

Background: The usage of the light emitting diode (LED) has been increasingly applied in the illumination setting and electronic equipment. However, the effect of LED lights on the retina remains unclear. In this study, we observed and analyzed the impact of white LED lights at different intensities on the function and morphology of rat retinas. Methods: Thirty-six Sprague-Dawley rats weighing 150–180 g were randomly divided into six groups (n=6 in each group) including a normal control (NC) group, 4 white LED groups at different light intensities (4,000, 6,000, 7,000, and 10,000 lux), and an ultraviolet B (UVB) lighting group (302 nm, 1,000 µw/cm 2 ). After 24 hours of continuous illumination, full-field flash electroretinogram (FERG) and pathological examination were performed in each group. Results: As revealed by FERG, the impairment of retinal function gradually worsened with the increase of LED light intensity. In contrast, the UVB group had the most severe retinal function impairment. Particularly, the functional damage of rod cells and inner nuclear layer cells was the main FERG finding in each group. In the NC group, the retina had typical morphologies featured by well-defined structures, clearly visible border between the inner and outer segments, and neatly arranged inner and outer nuclear layer cells. After 24 hours of illumination, the inner and outer parts of the retina in the 4,000 lux group were still neatly arranged, along with a clear border; however, the inner and outer nuclear layers were randomly arranged, and some irregular nuclei and cells were lost. The damage of the internal and external retinal segments and the internal and external nuclear layers became more evident in the 6,000 lux group, 7,000 lux group, and 10,000 lux group. The UVB group had a more obviously disordered arrangement of inner and outer nuclear layers and loss of cells. Conclusions: Continuous exposure to white LED light can cause structural and functional damage to rat retinas, and such damage is related to the intensity of illumination. Therefore, the risk of retinal damage should be considered during LED illumination, and proper LED illumination intensity may help to maintain eye health.

High photostability and luminescent efficiency of quantum dots: ultrathin epitaxial Al self-passivation layer with a homogeneous ligand

Semiconductor quantum dots (QDs) have aroused extensive interest in various applications because of their excellent optical and electronic properties. However, long-term photostability of the CdSe QDs has always posed application challenges. This study discusses the high-quality QDs synthesized using an uncomplicated coating method. The ultrathin epitaxial Al self-passivation layer is coated with a homogeneous ligand to maintain high luminescent efficiency and photostability of the QDs. The time-dependent intensity responses of the CdSe/CdS, CdSe/CdS/Al, and CdSe/CdS/CdS/Al QDs were verified under continuous irradiation using a single-particle one-watt blue light-emitting diode (LED). The CdSe/CdS photoluminescence (PL) intensity rapidly decreased under the blue LED illumination, whereas that of the CdSe/CdS/CdS/Al QDs remained almost unchanged for 300 min. The PL spectra of the three samples in 10–300 K were verified by comparing the temperature-dependent full-width at half-maximum of their emission energies and luminescent intensities. The mechanism of the temperature-dependent non-radiative relaxation of CdSe QDs coated with CdS layers of different thicknesses evolved from the thermal activation of carrier trapping by surface defects/traps in the CdSe QDs to the thermal escape of carriers in the core/shell QDs, assisted by multiple longitudinal–optical phonons. The luminescence mechanism was almost independent of the Al epitaxial growth layer.

Light-assisted recovery of reacted MoS2 for reversible NO2 sensing at room temperature

Two-dimensional (2D) nanomaterials have been extensively explored as promising candidates for gas sensing due to their high surface-to-volume ratio. Among many 2D nanomaterials, molybdenum disulfide (MoS2) is known to be functional in detecting harmful gases at room temperature; therefore, it has been actively studied as a gas sensing material. However, there has been a limitation in recovering the original signal from reacted MoS2 after exposure to the target gas. This work demonstrates the recovery of the initial resistance of reacted chemical vapor deposition-grown MoS2 by illuminating it with a UV light-emitting diode (LED). A novel mechanism involving photo-generated electron–hole pairs in MoS2 is proposed and experimentally verified. The fabricated sensor detects nitrogen dioxide (NO2) and distinguishes between concentrations from 1 to 10 ppm with the proposed recovery process. Reversible detection after repeated exposure to 5 ppm NO2 over eight cycles is achieved through UV–LED illumination for a short time during the recovery process, while the identical sensor without UV illumination shows a transitional response at each cycle. To apply a low cost gas sensing solution at room temperature, visible light LEDs are also used to recover the resistance of the reacted MoS2.

Insight into the synthesis and luminescence properties of the single-ion-activated single-phased Na3ScSi2O7:Dy3+ phosphor for white light-emitting diodes

In recent years, single-ion activated single-phase white phosphors played a crucial role in the field of near-ultraviolet (n-UV) white light-emitting diode (w-LED) illumination. In this work, a series of Na3Sc1–xSi2O7:xDy3+ phosphors was successfully prepared by high-temperature solid-state reaction method. The morphology and phase composition of the phosphors were confirmed by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Due to the 6H15/2 → 6P7/2 transition of Dy3+, the photoluminescence (PL) excitation spectrum of Na3Sc1–xSi2O7:xDy3+ exhibits a series of absorption peaks in the range of 250–450 nm and the strongest excitation peak is located at 349 nm. The PL spectra shows that the optimal doping concentration of Dy3+ is 0.13, which is controlled by dipole–dipole interaction according to the corresponding concentration quenching mechanism. The thermal stability of Na3Sc0.87Si2O7:0.13Dy3+ phosphor was investigated in detail and the compound has good thermal stability with activation energy of 0.198 eV. The decay time value of Na3Sc0.87Si2O7:0.13Dy3+ phosphor was calculated to be 0.4015 ms. The CIE chromaticity coordinates indicated that the phosphor produced warm white-light emission and testified the potential application of Na3ScSi2O7:Dy3+ as a new-style w-LEDs phosphor.

The Protective Effects of Blue Light-Blocking Films With Different Shielding Rates: A Rat Model Study.

PurposeTo examine light emitting diode (LED)-induced retinal photochemical damage and assess the protective performance of blue light-shielding films with different shielding rates in Sprague-Dawley rats (SD rats).MethodsSD rats were randomly divided into five groups: blank control (group I), white LED illumination (group II), and white LED illumination combined with shielding of blue light of wavelength 440 nm at 40%, 60%, and 80% (groups III, IV, and V). The illumination was 200 lux. All animals underwent electroretinography (ERG), hematoxylin-eosin (H&E) staining, immunohistochemical (IHC) staining, and transmission electron microscopy (TEM) observation after 14 days of dark-adaptation before illumination, after 14 days of cyclic illumination, and after 14 days of darkness for recovery following illumination.ResultsERG showed retinal functional loss after LED light exposure. However, retinal cell function was partly recovered after a further 2 weeks of dark adaptation. H&E staining and TEM revealed increases in photoreceptor cell death after illumination. IHC staining demonstrated that oxidative stress was associated with retinal injury. Although retinal light injury was discovered in the LED light-exposure groups, shielding 60% of blue light of wavelength 440 nm (bandwidth 20 nm) protected retinas.ConclusionsCyclic illumination of low light intensity (200 lux) for 14 days produced retinal degeneration; shielding 60% of blue light may protect retinas from light damage.Translational RelevanceThis study found the effective shielding rate that could protect retinas from light damage when shielding specific narrow-band harmful blue light; thus providing a more normative method for protecting eyes from blue light hazard.

Clipping-Enhanced Optical OFDM for Visible Light Communication Systems

Visible light communications (VLC), a new optical wireless communication technology that uses illumination light-emitting diodes as transmitters, requires a modulation scheme that is well suited to these devices’ nonlinear response. Optical orthogonal frequency division multiplexing (OFDM) is a promising technique to provide high-speed data transmission for VLC. However, the peak transmitted power limitation and nonnegative transmitted signal constraint of the lighting sources can result in nonlinear signal distortion from clipping. In this paper, we propose a novel optical OFDM scheme for VLC systems called clipping-enhanced optical OFDM (CEO-OFDM) that transmits via extra time slots the information clipped by the peak power constraint. CEO-OFDM sacrifices bandwidth to allow a higher modulation index to improve the signal to noise ratio and reduce the clipping distortion caused by the peak power limitation. From analytical and numerical results, the proposed CEO-OFDM provides better bit error rate performance and higher data rate than DC-biased optical OFDM, unipolar OFDM, and asymmetrically clipped optical OFDM. Furthermore, CEO-OFDM can provide a better illumination performance that supports light dimming.

On the LED Illumination and Communication Design Space for Visible Light Communication

Visible light communication (VLC) is a promising application for short-range wireless digital communications, presenting itself as a breakthrough for future lighting systems. The use of light emitting diodes (LEDs) as transmitters by modulating their light intensity requires the correct design from both illumination and communication perspectives. However, in face of worldwide efforts for efficient energy consumption, the modulation of light imposes an energy cost that VLC cannot avoid. It has been shown that the modulation of light intensity brings unavoidable extra power expense. Thus, this paper brings a deeper analysis of the LED concerning its operating limits and efficacy with joint illumination and VLC intended modulations. The study uses a static photometrical, electrical, and thermal model of the LEDs, in order to perform an analytical analysis regarding illumination and communication. Base modulation strategies supported by the IEEE 802.15.7 standard (PHY I and PHY II) were compared side-by-side with other classical modulation schemes, such as pulse amplitude modulation, phase shift keying, frequency shift keying, quadrature amplitude modulation, and orthogonal frequency division multiplexing, from an energy conversion point of view. The results mark the design space connecting a set of possible modulation schemes with the desired average total light flux. This analysis guides the selection of the modulation technique according to the available power for a VLC system when efficacy is constrained. Moreover, the results show that the thermal effects not only reduce LED efficacy, but also constrict possible operating conditions regarding VLC in terms of communication signal power.

Short communication: Mycosporine-like amino acids protect natamycin against photodegradation in milk exposed to fluorescent or light-emitting diode light

Natamycin has been used as a natural antimicrobial in dairy products, but the poor light stability of natamycin can limit usefulness in food products. Mycosporine-like amino acids are strong UV absorbers and might be useful as an additive to decrease light-induced degradations. Therefore, the objective of this study was to evaluate the photoprotective effect of mycosporine-like amino acids (MAA) in cow milk stored under 2 lighting conditions in retail commercial display cabinets with fluorescent and high intensity light-emitting diode illumination. When milk was exposed to both fluorescent and light-emitting diode light, natamycin degradation was very fast, and only 17.1 ± 0.9% of its original concentration was observed after 8 d at 4.0°C. On the other hand, by adding MAA into milk, natamycin was retained at 82.2 ± 0.9% and 92.2 ± 0.9% when low and high MAA levels were used, respectively. However, high MAA levels resulted in color changes. Therefore, MAA at low levels had a photoprotective effect for natamycin stability in cow milk exposed to light in refrigerated glass containers.

LED Illumination and Color Appearance of White-Balanced Images

ABSTRACTRecent studies revealed the failure of typical blue-pumped white light emitting diodes (LEDs) in rendering the white appearance of surface colors, which was caused by the lack of ultraviolet (UV)/violet radiation to excite the fluorescent whitening agents (FWAs). The effect of such a failure on image color appearance has not been previously investigated, though white surfaces are important in image white balance. In this study, two 6500 K sources—one containing a normal level of UV/violet radiation to simulate CIE standard D65 and the other containing a low level of UV/violet radiation to simulate typical blue-pumped white LEDs—were created to illuminate a Macbeth ColorChecker and three whiteness standards containing different amounts of FWAs. The scene was captured and white balanced using nine different algorithms. Though the two sources caused small color differences to the ColorChecker, both physically (ΔE*ab = 1.44) and in the unbalanced images (ΔE*ab = 2.53), the source with a low level of UV/violet radiation caused noticeable color shifts to the ColorChecker in the white-balanced images regardless of the algorithms. Furthermore, the chromaticities of the three whiteness standards were all shifted toward the origin in the a*–b* plane under the source with a low level of UV/violet radiation in the white-balanced images regardless of the algorithms, making them appear more similar to each other. Overall, the findings suggested the great impact of typical blue-pumped white LEDs on image color appearance.

Impact of urban street lighting on road users’ perception of public space and mobility behavior

Refitting public spaces with light-emitting diode (LED) technology in lieu of conventional luminaires bears the risk of compromising lighting quality that road users have already adapted to; this is because the LED technology has been well tested indoors, but it has not been necessarily evaluated outdoors. Further insight into the effects of street lighting on road users is necessary to resolve potential deficiencies of available technologies. This study compares the effects of three different lighting scenarios (conventional lighting, state-of-the-art LED, optimized LED) on road users via surveys (N = 598 persons) and observations (N = 1341 persons) in the city of Vienna. In terms of the uniformity of street illumination and the comfort it provides, the results show the positive effects of LED street lighting both on surveyed pedestrians and vehicle drivers. The observations of pedestrian walking behavior revealed an unexpected result—no significant differences were noted apart from a more centric walking path along the sidewalk under LED illumination, particularly with the optimized LED luminaire.

A Novel, Low-Cost, Wide-Field, Infant Retinal Camera, "Neo": Technical and Safety Report for the Use on Premature Infants.

PurposeTo report the technical aspects, systemic, and ocular safety of a novel, low-cost, wide-field, infant retinal camera for use on premature infants.MethodsThe device, the “3nethra Neo” (Neo) is a 120° portable, contact, wide-field, unibody camera, with a CMOS sensor (2040 × 2040 resolution) and a warm light-emitting diode (LED) illumination source. The Neo was used to image 140 awake, preterm infants between postmenstrual age (PMA) of 28 to 37 weeks, undergoing retinopathy of prematurity (ROP) screening. Baseline, ‘during procedure', at 5 minutes, and for 60 minutes postprocedure, readings of oxygen saturation and heart rate were recorded. The device design, optics, illumination, and software specifications were compared with the RetCam 3.ResultsStudy defined bradycardia (9 infants, 6.4%), tachycardia (3 infants, 2.1%), and hypoxia (2 infants, 1.4%) were observed but there were no clinically significant systemic changes that required intervention during or following any of the study time intervals. There was a transient increase in heart rate by 9.68 (7.53–11.83; P < 0.0001) and marginal decrease in oxygen saturation (−1.94 [−1.60 to −2.28], P < 0.0001), which started to return to baseline 5 minutes after the procedure. Transient redness was seen in two eyes (0.7%) of two infants. No other ocular adverse effects were observed.ConclusionsThe Neo is easy to use in preterm infants and being compact was readily portable. There were no significant ocular or systemic adverse effects, potentially allowing it to be a viable low-cost device for ROP screening in low resource settings.Translational RelevanceThe camera provides a safe and affordable alternative to image the retina of infants by using novel illumination and lens mechanics and has the potential of worldwide acceptance.

Development of a Low-Cost Multi-Waveband LED Illumination Imaging Technique for Rapid Evaluation of Fresh Meat Quality

Determining the quality of meat has always been essential for the food industry because consumers prefer superior quality meat. Therefore, the food industry requires the development of a rapid and non-destructive method for meat-quality determination. Over the past few years, a number of techniques have been presented for monitoring meat–chemical attributes. However, most previous techniques are quite expensive, destructive, and require complex hardware to operate. Thus, in this work, we demonstrate a low-cost sensing technique (eliminating the expensive equipment and complicated design) for meat–chemical quality detection. The newly developed system was integrated with a low-cost monochrome camera and ordinary light-emitting diode (LED) light sources, with fifteen different wavebands ranging from 458 to 950 nm. The monochrome camera captures images of the meat sample across a spectral range from 458 to 950 nm using a single snapshot method. The chemical values (e.g., moisture, fat, and protein) were also determined using conventional methods. The collected images were combined to produce a multispectral data cube and to extract spectral data. Partial least squares (PLS) and support vector regression (SVR) modeling were used on the extracted spectra and chemical values. The developed models for meat samples displayed accurate chemical-component prediction ( R 2 &gt; 0.80). Our model, based on a monochrome sensor using only fifteen wavebands, provided reasonable results compared with the previously developed expensive spectroscopic techniques. Therefore, this complementary metal-oxide semiconductor (CMOS) based multispectral sensing technique may have the potential to detect meat quality, thereby facilitating a simple, fast, and cost-effective method applicable to small-scale meat-processing industries.