Search

Blue light comprises the electromagnetic spectrum between approximately 380-500 nm. The sun is the main source of blue light, although we also receive emissions of this type of light by electronic devices and artificial lighting. Changes in lighting systems and lifestyle habits have led to the questioning of exposure to blue light emitted by artificial sources as a possible health problem. Faced with this potential problem, ophthalmic lens laboratories brought to market lenses with specific treatment against hazard blue light emitted by electronic devices. In this work we measure the spectral transmittance of 6 blue filter ophthalmic lenses from 4 different laboratories, Essilor, Hoya, Shamir and Kodak. We face the transmission spectra measured with the emission spectra of 3 different electronic devices, to be able to discuss the suitability of these blue filter lenses for use with electronic devices. We conclude that the transmittance of blue filters in the maximum blue light emission range is high above 90%, and that changing the correlated color temperature of electronic devices results in a greater reduction in exposure to hazard blue light. We also found that Shamir's Blue Zero and Essilor's Eye Protect System lenses block UVA light and have low transmittance in the range of 380- 420 nm, so they would be more effective for protection against blue light outdoors than for use with electronic devices.

This study evaluated a new light-emitting diode (LED-S) photic stimulator and compared skin electroretinogram (ERG) responses obtained to those evoked by the Grass Instrument stimulator (GP-S). Two sub-studies were combined to evaluate the difference in responses resulting from the LED-S and GP-S stimuli. The first was a photometry study that matched the LED-S stimuli to the GP-S. In the second study, electroretinograms (ERGs) were recorded under scotopic and photopic conditions using stimuli each stimulator. The stimuli were matched photometrically to measurements obtained from the photometer located 30 cm in front of the stimulators. In addition, the ERG responses were recorded from the LED stimulator when photometrically matched to the GP-S blue stimulus presented through a ganzfeld. The amplitudes and time peaks of the resulting ERG a- and b-waves were then measured and compared using paired T-tests. Study 1: The LED-S was matched to the GP-S at various intensity settings measured 30 cm away from the stimulator. Measurement through a ganzfeld full-field stimulator (GFFS) demonstrated that the GP-S had a significant hot spot centrally. Study 2: Photometrically matched ERGs evoked by both stimulators while employing the direct head-on measurements demonstrated multiple similarities. Similarities included component morphology, amplitude and implicit time across the two stimulators, excluding the rod-driven stimulus (GP-S setting employing a blue filter). Differences between the rod-driven ERGs evoked by the GP-S and LED-S while employing head-on photometric measurements were due to the significant difference in intensities between the two stimulators. The GP-S and LED-S evoked similar rod-driven ERG responses when they were matched using the GFFS photometrically matched intensities protocol. A hand-held stimulator is essential when recording ERG’s in the practice of paediatric visual electrophysiology. The LED-S can match the GP-S stimulus intensities, making it a potential replacement for the GP-S. In addition, the LED-S has uniform intensity across the surface of the device compared to the GP-S, is silent for standard stimuli and can generate prolonged duration stimuli for the recording of on–off ERGs.

In this study we observed and determined the period of the eclipsing binary star EPIC 201458798, finding that its period has not changed since it was last measured and published in the Kepler catalog in 2014. We did this by developing Python code to determine the period using two independent algorithms and partially automating the search for suitable comparison stars. Our system was imaged by the 0.4m Las Cumbres Observatory telescopes in four filters. We analyzed six photometry types returned for each image from the Our Solar Siblings pipeline. Of these photometries, we found source extractor kron (sek) to be the most appropriate type for our 2x2 binned images of EPIC 201458798. Both of the period-finding algorithms we developed gave results that were not statistically different from the Kepler catalog period for the infrared, red, and visual filter images. The blue filter images were statistically different fromthe Kepler catalog period for one of our algorithms but not the other.

To investigate the effect of contact lenses with blue light filters on contrast sensitivity and any alteration in tear quantity and quality.This prospective longitudinal pilot study required three visits by each participant. Monocular visual acuity, contrast sensitivity, phenol red thread test, and tear breakup time were measured at each visit.There were significant differences in logarithmic contrast sensitivity between the groups. The breakup time (BUT) was significantly lower after using video display terminals than before (P0.05). No differences in BUT were found between groups video display terminals and contact lenses having the blue filter (P0.05). However, higher mean values were observed in the group after video display terminal use with contact lenses having the blue filter than that with standard contact lenses (P0.05 in both groups). Furthermore, the mean value of phenol red thread test on the group after video display terminal use with contact lenses having the blue filter was lower than the group before its use (P0.05).The results establish a possible relationship between tear stability, improved contrast sensitivity, and the use of a blue filter in contact lenses.

The non-linear filter is subject to divergence for close-range target tracking; an adaptive best linear unbiased estimation (BLUE) filter with fused range estimation is presented. After proposing the notion of predicted range, the weighted estimation of the predicted and measured ranges is used in the converted measurement model to track the target. The adaptive BLUE filtering parameters with Rayleigh range measurement are derived. Simulation results show the adaptive BLUE filter exhibits better robustness and accuracy with modest computational burden.

Background and Objectives: This retrospective consecutive case control study compares best-corrected visual acuity (BCVA), mesopic contrast sensitivity (CS), color vision, and glare between a group of eyes with blue-light-filtering intraocular lenses and another with UV-light-filtering intraocular lenses. Materials and Methods: We used Early Treatment Diabetic Retinopathy Study charts to compare BCVA, Rabin charts for mesopic CS testing, Oculus HMC Anomaloscope MR to test for chromatic discrimination, and Oculus Mesotest II to measure scotopic CS with glare. For analysis, we used descriptive statistics and compared means with parametric and non-parametric tests. The level of significance was set as α = 0.05. Results: For the group with the blue-light-filtering intraocular lens, the average results were BCVA = 0.96 (SD ± 0.09), CS = 1.78 log (SD ± 0.12), chromatic discrimination results M = 63.91 (SD ± 11.88), R = 60.07 (SD ± 7.89). For mesopic CS with glare, the group achieved on average 2.54 (SD ± 1.50) points out of 4. For the group with the UV-light-filtering intraocular lens, the average results were BCVA = 0.93 (SD ± 0.14), CS = 1.79 log (SD ± 0.13), chromatic discrimination results M = 65.38 (SD ± 17.14), R = 60.79 (SD ± 10.39). For mesopic CS with glare, this group achieved an average of 2.79 (SD ± 1.53) points out of 4. Conclusion: No significant differences (p &gt, 0.05) were found in any of the tested parameters between the analyzed groups. Slight shift in color vision was observed, although not statistically significant.

Fluorescence-guided surgery with five-aminolevulinic acid (5-ALA) is the state-of-the-art treatment of high-grade gliomas. However, intraoperative visualization of 5-ALA under blue light remains challenging, especially when blood covers the surgical field and thereby fluorescence. To overcome this problem and combine the brightness of visible light with the information delivered with fluorescence, we implemented multispectral fluorescence (MFL) in a surgical microscope, a technique that is able to project both information in real-time. We prospectively examined 25 patients with brain tumors. One patient was operated on two different lesions in the same setting. The tumors comprised: six glioblastomas, four anaplastic astrocytomas, one anaplastic oligodendroglioma, two meningiomas, 11 metastatic tumors, one acoustic neuroma, and one ependymoma. The MFL technique with a real-time overlay of fluorescence and white light was compared intraoperatively to the classic blue filter. All lesions were clearly visible and highlighted from the surrounding tissue. The pseudocolor we chose was green, representing fluorescence, with the surrounding brain tissue remaining in its original color. When blood was covering the surgical field, orientation was easy to maintain. The MFL technique opens the way for precise and clear visualization of fluorescence in real-time under white light. It can be easily used for the resection of all tumors accumulating 5-ALA. Drawbacks of classic PpIX fluorescence such as hidden fluorescence, intraoperative changes could be overcome with the presence of additional white light in MFL technique.

Aim. The objective of the study was to substantiate the rationality of using monochromatic polarized incoherent optical radiation (photochromotherapy) on the abdomen as a supplement to the standard program for the treatment of acute intestinal infections in children. Material and methods. Twenty-six children with acute intestinal infections from 6 months to 12 years old were observed during inpatient treatment. In the comparison group (n = 11), children received standard therapy, including diet therapy, rehydration, sorbents, probiotics or prebiotics, as well as indications for etiotropic drugs. In the main group, patients (n = 15) in addition to standard therapy received photochromotherapy as an effect on the abdomen with monochromatic polarized incoherent optical radiation from the Bioptron apparatus with a blue filter at a distance of 5 cm labile along the bowel. The duration of photochromotherapy was 5 minutes, the course of treatment included 4-5 sessions 1 time per day. The effectiveness of the therapy regimens used in the groups was assessed by the duration of the disease, the length of inpatient treatment, the dynamics of changes in the clinical blood test at the time of discharge. Results. The advantage of the technique with the addition of standard treatment of acute intestinal infections by photochromotherapy was established. In the main group of patients, the duration of the disease was significantly shorter (9,1±0,8 days) compared to the comparison group (10,2±1,5 days, p=0,02) against the background of a significant decrease in the severity of inflammatory manifestations in the hemogram in form of a decrease in thrombocytosis. Conclusion . The obtained data make it possible to recommend the method of photochromotherapy in the complex therapy of intestinal infections of various etiologies in children older than 6 months.

In this paper, data transmission using a white LED and blue filter is demonstrated. The conventional white LEDs are produced by combining blue LEDs with yellow phosphor coating. This combination generates white light. However, the yellow phosphor coating has bandwidth limiting effect. As a result, the data rate of the transmission is limited. One of the method that can be used to cope this effect is by employing blue filter at the receiver. This method filters out the yellow components. To test the method, an experimental SoC-based test-bed using a HW/SW co-design approach is developed.

2nd International Conference on Advanced Communication Technologies and Networking, CommNet 2019 -- 12 April 2019 through 14 April 2019 -- -- 148920 This paper proposes a means to maximize the data rate supported by a visible light communication (VLC) system. The investigated VLC system uses phosphor-coated white light emitting diodes (LEDs), which are common in existing illumination systems but are also known to limit the communication system's data rate. In this paper, we propose a remedy to such a limitation by adding a response-flattening filter at the receiver's end to mitigate the effect of the slow yellow phosphor spectral component. An experimental study is conducted to evaluate the validity of the proposed remedy. The resulting performance is compared with an existing remedy that involves adding a blue filter at the receiver. Off-the-shelf commercial filters are used in the experiment. Enhanced bit-error-rates (BERs) and signal-to-noise ratios (SNRs) at high data rates are observed. Specifically, our experimental work demonstrates that BER is enhanced by 40% and 15% for data rates up to 12 Mbps when responseflattenina filter and blue filter are adopted, respectively. © 2019 IEEE.

Consumers are demanding foods with high sensory and nutritional quality including a higher content of compounds that help maintain good health. Given this scenario, new technologies are emerging to produce fresh salads that have the characteristics currently in demand. Shade nettings or photoselective filters on fruit and vegetable crops are a technology that provides protection, modifies the light spectrum resulting in a higher accumulation of antioxidant compounds, making them more desirable to consumers. The objective of this study was to compare the effect of shade netting on the fresh quality parameters of baby leaf spinach grown in a hydroponic system at harvest and after a period of 10 days at 4 °C. By using different shade netting colors, the average photosynthetic photon flux density (PPFD) that reaches the plants was modified during the growing period of baby leaf spinach (red: 118.35 μmol m−2 s−1; blue:117.96 μmol m−2 s−1; gray: 63.18 μmol m−2 s−1 and control without shade nettings: 278.12 μmol m−2 s−1). At harvest, baby leaf spinach grown under the red shade netting reached the highest yield. However, with the blue filter, leaves showed a value of 9.3 % dry weight, significantly higher than the values from red and gray filters with values of 7.3 and 6.3 %, respectively. The phenolic compound contents reached significantly higher values of 485.5 mg gallic acid equivalent (GAE) per 100 g−1 FW for the baby leaf spinach grown under the red filter compared to the blue, gray and control filters with values of 472.5; 387.6 and 316.5 mg GAE per 100 g−1 FW, respectively. The antioxidant capacity was significantly higher under the red filter. The sensory quality parameters indicated that spinach grown under color filters did not show off-flavors and maintained its turgidity and appearance at harvest. In the postharvest period, baby leaf spinach grown under red filter maintained the highest total phenol content and antioxidant activity after 10 days at 4 °C with similar appearance and turgidity as the control.

In manoeuvring target tracking, a primary tradeoff is the robust tracking of manoeuvres against the accurate tracking of constant velocity (CV) motion. To achieve this goal, an interacting multiple model (IMM) algorithm fusing input estimation (IE) and best linear unbiased estimation (BLUE) filter is presented. First, the constant input assumption of IE is modified to track possible manoeuvre fluctuation. Then, an innovation sequence modification technique is proposed so manoeuvre can be detected and estimated sequentially. With improvements above, a modified input estimator (MIE) is designed to track varying manoeuvres. In view of the optimal tracking of BLUE filter for CV motion, MIE and BLUE filter are fused within IMM framework to generate an overall adaptive tracking algorithm. Simulation results reveal the proposed approach yields better accuracy for CV tracking and robustness for manoeuvre tracking.

16th International Multi-Conference on Systems, Signals and Devices, SSD 2019 -- 21 March 2019 through 24 March 2019 -- -- 154292 This paper experimentally evaluates the performance of visible light communications (VLC) systems employing phosphor-coated white light emitting diodes (LEDs). Phosphor-coated white LEDs though widely used commercially, are known to limit the system's maximum data rate. Such a limitation is conventionally treated by two methods: either adding a blue filter at the receiver or using orthogonal frequency multiplexing (OFDM) digital modulation technique. Adding a blue filter at the receiver is controversial in current literature and claimed to decrease the signal-to-noise-ratio (SNR) or to be inefficient if OFDM is employed. Hence, in this work, we experimentally evaluate the above OFDM based VLC system with and without a blue filter. Results are compared to prove that adding a blue filter at the receiver boosts SNR and bit-error-rate (BER) values. This, in turn, helps maximize the data rates supported by such systems. The addition of a blue filter is tested with different modulation techniques. Results in this work remove the controversy around employing a blue filter in OFDM based VLC systems with phosphor-coated white LEDs. Improved BERs and SNRs at high data rates are observed. Specifically, this experimental work demonstrates a BER enhancement of ?40% and ?15% for data rates up to 12 Mbps when a blue filter is added. © 2019 IEEE. Texas A and M University, TAMU: 2019 -- insignificant effect if OFDM is employed. In this work, we experimentally assess the above OFDM based VLC system with and without adding a blue filter. Comparing results prove that adding a blue filter at the receiver’s end improves BER values by ?35% to ?47% according to the modulation type used. Results from this work show the following: • It removes the doubts that blue filters neg-atively affect the SNR. Despite reducing the signal power by suppressing the slow yellow spectrum, blue filters reject ambient noise in the visible spectra. Thus, the resulting SNR is elevated. • Blue filters continue to boost the system’s per-formance in terms of SNR and BER in VLC systems employing OFDM. Hence, the claim that blue filters maybe of no use while using OFDM is proven wrong. • Combining adding a blue filter along with adopting OFDM results in improved BERs and SNRs at high data rates. In specific, this experimental work depicts a BER reduction of 40% and 15% for data rates up to 12 Mbps when a blue filter is added with the presence of OFDM modulation. ACKNOWLEDGEMENTS This work was supported by the Texas A&M University at Qatar (TAMUQ) responsive research seed grants 2019. --

A novel interacting multiple model based on BLUE filter (IMM-BLUE) for tracking a maneuvering target using radar/ESM heterogeneous sensors is presented in this paper. Under the architecture of the proposed algorithm, the interacting multiple model (IMM) deals with the model switching, while the BLUE filter accounts for non-linearity in the dynamic system models. The simulation results show that the presented IMM-BLUE has higher tracking precision than the IMM-DCM, and IMM-EKF.

This paper presents an extended BLUE filter with Pitot tube and windspeed measurements. Though widely used in aviation, Pitot tube is ignored by scholars because it only measures the speed of an aircraft relative to the air. Investigation shows the linear combination of Pitot tube and windspeed measurements can yield aircraft velocity estimation to improve performance. After a thorough analysis of the relationship between measurements and target state, an extended BLUE filter model is built, filter parameters are derived. Extensive simulation comparisons with other state-of-the-art methods verify the proposed method is accurate and computationally efficient.

High paralarvae mortality is a major bottleneck currently hindering the control over the lifecycle of common octopus (Octopus vulgaris Cuvier, 1797). It is believed that this problem might be related to either zoo-technical and/or nutritional aspects. The present paper is focused on the study of different zoo-technical aspects related to light conditions on the rearing of paralarvae, including the effects of polarization in prey ingestion, the use of a blue filter to simulate natural conditions, and the use of focused light to avoid reflections of the rearing tank’s walls. In the first experiment, O. vulgaris paralarvae ingestion of Artemia sp. and copepods (Tisbe sp.) was assessed under either normal or polarized light. In the second experiment, the effect of a blue filter with natural light or focused artificial light on growth and mortality was assessed over 15 days of rearing. Ingestion rate was not influenced by light polarization. Nonetheless, a significantly higher ingestion of Artemia sp. with respect to copepods was observed. The blue filter promoted the use of natural light conditions in Octopus paralarval culture, while focused light reduced the collision of the paralarvae against the walls. However, no significant differences were found in paralarval growth nor survival, SI

For an indoor Visible Light Communication system with phosphorescent LEDs, we show a blue receive filter is particularly suitable for cool-white LEDs but less attractive for warm-white LEDs. Distance and sunlight also influence whether a blue filter should be used.

This study is a comparison of the performance of the Leeds Spectral Vision system (infrared and 455 nm) with the Polilight-Flare® Plus UV (365 nm) and the Mini-CrimeScope 400 CSS (485 nm) filter for detecting biological stains (blood, semen, saliva and urine) on a variety of fabric substrates. The samples included neat and diluted stains (1/2, 1/10, 1/50 and 1/100), layered stains and stains prepared using different volumes of fluids (20, 10 and 3 μL) to observe the sensitivity of different filters. The detection of blood in the presence of stains created by household materials that appear visibly similar to blood under ambient lighting was also assessed. The detection of biological stains from blood, semen and urine (10 μL) and saliva (100 μL) were also assessed on three brands of diapers. The blue filter was the optimal choice for the detection of bodily fluids that fluoresce (semen, saliva and urine), performing equally or better than the ultraviolet and outperforming the infrared. The infrared...

We propose a multi-band OFDM modulation for wireless VLC system together with dynamic bandwidth allocation. In addition, the proposed modulation format also can enhance the maximum VLC traffic rate to 17.8% without using blue filter.

Introduction Virtual chromoendoscopy is used to enhance surface patterns and colour differences. One type of virtual chromoendoscopy is the Fuji Intelligent Colour Enhancement (FICE). Although widely applied in conventional endoscopy, data on FICE application in capsule endoscopy are limited. Furthermore, the validity of Blue filter (feature of RAPID® software) has not been examined. Aim/s We aimed to qualitatively evaluate the use of FICE and Blue filter enhancement, in images of lesions obtained during small bowel capsule endoscopy, comparing them with similar, conventional (white light) images. Methods A total of 167 images (6 different lesion categories) obtained from 200 capsule endoscopy examinations. Two gastroenterologists examined the images with white light, FICE and Blue filter in regards to the visibility of blood vessels, the contrast of the mucosal surface, and the demarcation of lesion borders. The agreed scores were: improved, similar, worse. Inter-observer agreement was calculated. Results For all lesion categories, Blue filter provided image improvement (compared to white light) in 83%, (inter-observer agreement: 0.786). With FICE 1, improvement was observed in 34%, worse image in 55.9%, (inter-observer agreement: 0.646). With FICE 2, improvement was observed in 8.6%, worse in 77.5%, (inter-observer agreement: 0.617). With FICE 3, improvement was seen in 7.7%, worse in 79.9% (inter-observer agreement: 0.669). Conclusion Comparing with FICE, Blue filter offers better image enhancement in capsule endoscopy.

The unprecedented and ever-growing number of Web videos nowadays leads to the massive existence of near-duplicate videos. Very often, some near-duplicate videos exhibit great content changes, while the user perceives little information change, for example, color features change significantly when transforming a color video with a blue filter. These feature changes contribute to low-level video similarity computations, making conventional similarity-based near-duplicate video retrieval techniques incapable of accurately capturing the implicit relationship between two near-duplicate videos with fairly large content modifications. In this paper, we introduce a new dimension for near-duplicate video retrieval. Different from existing near-duplicate video retrieval approaches which are based on video-content similarity, we explore the correlation between two videos. The intuition is that near-duplicate videos should preserve strong information correlation in spite of intensive content changes. More effective retrieval with stronger tolerance is achieved by replacing video-content similarity measures with information correlation analysis. Theoretical justification and experimental results prove the effectiveness of correlation-based near-duplicate retrieval.

We have obtained imaging polarimetry of the comet C/2013 R1 (Lovejoy) with 2-Channel-Focal-Reducer Rozhen instrument at 2m Ritchey-Chr\'etien-Coud\'e telescope of the Bulgarian National Astronomical Observatory Rozhen in two dust continuum filters covering wavelength intervals clear from molecular emissions and centred at $4430\AA$ in (blue filter) and at $6840\AA$ in (red filter). In imaging mode we measured the degree of linear polarisation $17.01\pm0.09$% in the blue and $18.81\pm0.02$% in the red, which is in a very good agreement with measurements of other comets at the similar phase angle. We have also obtained polarisation maps in both filters. We found a strong correlation between the spatial distribution of the polarisation and the dust colour. Spectropolarimetry of the nucleus region shows an increase of the polarisation with wavelength, and a depolarisation in the spectral regions with gas emission lines, most noticeable in C$_2$ emission band, which shows a polarisation of $6.0\pm1.1$%., Comment: 6 pages, 8 figures, ACM2014 conference proceedings