Bright Illumination Research Articles

Controlling single-photon detector ID210 with bright light.

We experimentally demonstrate that a single-photon detector ID210 commercially available from ID Quantique is vulnerable to blinding and can be fully controlled by bright illumination. In quantum key distribution, this vulnerability can be exploited by an eavesdropper to perform a faked-state attack giving her full knowledge of the key without being noticed. We consider the attack on standard BB84 protocol and a subcarrier-wave scheme and outline a possible countermeasure.

A mobile vision inspection system for tiny defect detection on smooth car-body surfaces based on deep ensemble learning

Defect inspection of car-body surfaces is a crucial step for assessing the appearance quality of car coatings. However, some problems such as uncertain imaging conditions, complicated local areas of car-body surfaces and tiny defects with ambiguous edges and low contrast in large images make defect detection more challenging. In order to overcome these challenges, a novel mobile inspection system based on computer vision technology is developed to inspect tiny defects on smooth car-body surfaces automatically. In our system, a dedicated image acquisition module (IAM) with a high-resolution camera, plane light-emitting diode light source and laser rangefinder is designed to capture surface images over bright field illumination. A specific deep ensemble learning algorithm, named TinyDefectNet, is proposed to identify tiny defects in large images acquired from the IAM online. The experiment results indicate our inspection system is on par with the average performance of experienced inspectors but it is much faster than artificial visual inspection. The developed inspection system has been successfully deployed in practice at a car coating plant and it has made inspection more efficient.

Research on energy‐saving power system of office building lighting based on Internet of Things

In order to solve the problem of lighting waste in developing countries and backward areas, an application of Internet of Things technology, combined with edge computing, is proposed to achieve intelligent lighting system for office buildings. The system takes the Internet of Things technology as the core, and combine ZigBee short-distance, low complexity, low-rate, low-power, low-cost and two-way wireless communication advantage, and based on mesh topology designs an energy-saving system for office building lighting. Intelligently control the switch of the luminaire or switch the preset illumination mode according to the sensed number of people in the current office, location and illumination brightness, effectively overcomes the defects of traditional lighting mode management backwardness, waste of energy, poor comfort and complicated wiring. The objective is to achieve the goal of energy saving and consumption reduction for office building lighting. Through practice and experimental test analysis, the improved energy consumption of the energy saving is about 30% per year, and the effect is remarkable.

Efficient Office Assistant Robot System: Autonomous Navigation and Controlling Based on ROS

This paper proposes a movable robot that can be used to deliver documents or small parcels (>2.0kg) between employees of an unstructured indoor office environment. The study reviews literature on robot navigation, apply promising techniques and test their accuracy in an unstructured indoor laboratory environment. There are many technologies available in robot navigation. We have selected free and open source software and inexpensive sensors and materials to build a low cost but accurate robot. Our system comprised of three units: first one that process sensor data, second one which is the navigating robot having sensors and actuators, and third one controlling part of office assistant robot system. We have used Robotic Operating System (ROS) indigo as the ground operating system in the background of Ubuntu Operating System. The experiment was conducted to examine the capabilities of the setup and studied its behavior, mapping and localization specifically according to the user commands. An unstructured indoor environment was selected with five users located on the sides. We considered both dark (55 lux – 60 lux) and bright (15 lux – 20 lux) illumination conditions in the room. Then, we allowed the robot to navigate autonomously according to the user commands between five users and monitored its accuracy by looking at the completion of the route to a target user. Results show that the robot has about 98.4% of accuracy of achieving the goal location on average in both lighting conditions and 98% and 98.8% of accuracies for bright and dark conditions respectively. Finally, this office assistant robot system could be practically used in an office environment in both bright and dark lighting conditions.

Effects of Food Environments and Eating Environments on Consumers’ Food Consumption Volume

Even though the influences of eating environments and the food environments on consumption have been discussed, little has been done to examine whether the food environments would be influenced by the eating environments. For example, the size of plate has been proved to have impact on consumers’ consumption volume; it is still unknown whether the eating environment would interact with the food environment and in turn influences consumers’ consumption volume. This research explores the underlying mechanisms how consumers are influenced by the size of bowl when they consume food. In addition, eating environments are also incorporated to discuss their effects on the relationship between bowl size and consumers’ consumption volume. The results indicate people who receive a large bowl with large chopsticks exhibit greater food consumption than those who receive a small bowl with small chopsticks. However, when people use tableware inconsistently, they exhibit similar food consumption. Under bright illumination, people given large bowls with large chopsticks exhibit greater food consumption than those given small bowls with small chopsticks; however, when people use inconsistently sized tableware, they exhibit similar food consumption. Under dim illumination, no significant differences in food consumption amount are evident in association with bowl and chopstick sizes.

Combined staining of elastic and collagen fibers for histopathological and differential diagnosis in aorta pathologies

ABSTRACTHistochemical techniques are important for diagnosis of connective tissue fibers involved in different aorta pathologies. The aim of this study was to develop a histochemical staining method that identifies both elastic and collagen fibers simultaneously in the same section of aortic wall. Fragments of aorta from deceased dogs were processed according to standard histological technique for paraffin embedding. Sections were stained with orcein with counterstained with either light green or single step Gomori trichrome, and also orcein stain and picro-sirius red. Orcein stain combined with picro-sirius red allowed visualization of both elastic fibers (brown) and collagen fibers (red) with light microscopy using bright field illumination. Moreover, under polarized light microscopy only collagen fibers were detected, appearing as reddish birefringent fibers, confirming that picro-sirius red-stained fibers were collagen fibers. The combination staining by orcein and picro-sirius solutions provided visualization of both collagen and elastic fibers in the same section, facilitating identification of these connective tissue fibers in the aortic wall.

Details preserved brightness equalization algorithm for non-uniform illumination images

In order to overcome the limitation of current image enhancement algorithms for non-uniform illumination images, a brightness equalization algorithm is proposed to preserve the detail information in low illumination region and normal illumination region at the same time. The algorithm uses the adjacent frequency and position of pixels to generate illumination filter, so it can effectively separate illumination information and reflection information with details. The illumination threshold is used to divide different illumination areas to compensate for low illumination brightness, so as to balance the image brightness. The experimental results show that compared with the classical naturalness preserved enhancement algorithm (NPEA), the average peak signal to noise ratio of the image increases by 15.4%, the average enhancement degree increases by 245.0%, and the average brightness step difference decreases by 25.4%. The results of the proposed algorithm can maintain the details of different illumination areas while balancing the brightness and obtain a better visual effect.

Humans Trust Central Vision More Than Peripheral Vision Even in the Dark

SummaryTwo types of photoreceptors in the human retina support vision across a wide range of luminances: cones are active under bright daylight illumination (photopic viewing) and rods under dim illumination at night (scotopic viewing). These photoreceptors are distributed inhomogeneously across the retina [1]: cone-receptor density peaks at the center of the visual field (i.e., the fovea) and declines toward the periphery, allowing for high-acuity vision at the fovea in daylight. Rod receptors are absent from the fovea, leading to a functional foveal scotoma in night vision. In order to make optimal perceptual decisions, the visual system requires knowledge about its own properties and the relative reliability of signals arriving from different parts of the visual field [2]. Since cone and rod signals converge on the same pathways [3], and their cortical processing is similar except for the foveal scotoma [4], it is unclear if humans can take into account the differences between scotopic and photopic vision when making perceptual decisions. Here, we show that the scotopic foveal scotoma is filled in with information from the immediate surround and that humans trust this inferred information more than veridical information from the periphery of the visual field. We observed a similar preference under daylight illumination, indicating that humans have a default preference for information from the fovea even if this information is not veridical, like in night vision. This suggests that filling-in precedes the estimation of confidence, thereby shielding awareness from the foveal scotoma with respect to its contents and its properties.

Deformation of cellular components of bone forming cells when exposed to a magnetic field

It has been suggested that alignment control of biological macromolecules and structures is possible when the diamagnetic energy is sufficient to overcome the thermal energy. Strong magnetic fields of several Tesla (T) have previously been shown to enable the observation of the magnetic orientations of protein fibers and suspended or adherent cells. In the present study, the fine structure of a bone-forming osteoblast cell line was observed in real-time under strong static magnetic fields of up to 5 T. The magnetic field was applied normal to the adhering surface, and induced slight deformation of cellular shape under bright field illumination. A newly developed dark field observation method presented more precise analysis of the inner structures of the cells in strong magnetic fields. Specifically, structures with a round appearance were clearly visualized around the cell nucleus using the electromagnetic illumination. In addition to the magnetically induced swelling of the round structures—which showed differences in diameter of several micrometers—color changes for these intracellular components were also detected using this technique. A high-resolution analysis of fine cellular structure based on the magnetic orientation of intracellular components including microtubules is proposed.

Light-Dependent Electrical Activity in Sea Urchin Tube Feet Cells.

Sea urchins can detect and respond to light, and many species of sea urchins are negatively phototaxic. Light detection is hypothesized to occur via photoreceptors located on sea urchin tube feet, and opsins have been detected in tube feet, spines, and the test. However, the molecular mechanisms underlying light detection are, for the most part, unknown. Individual tube feet disc cells were isolated from purple sea urchins (Strongylocentrotus purpuratus), and the electrical responses of these cells to varying levels of illumination were quantified using the patch clamp technique. No currents were observed under bright illumination, whereas under dark conditions, large, slowly activating currents were consistently observed. Two types of cells were functionally identified based on their responses to darkness. Type I cells sustained currents indefinitely in the dark, whereas Type II cell currents spontaneously decayed after several seconds. The large currents observed were composed of the summation of many smaller events that were characterized by a rapid onset and an exponentially decaying component, which may be indicative of direct vesicular release from the tube feet disc cells in response to the dark conditions.

A multi-mode digital holographic microscope.

We present a transmission-mode digital holographic microscope that can switch easily between three different imaging modes: inline, dark field off-axis, and bright field off-axis. Our instrument can be used: to track through time in three dimensions microscopic dielectric objects, such as motile micro-organisms; localize brightly scattering nanoparticles, which cannot be seen under conventional bright field illumination; and recover topographic information and measure the refractive index and dry mass of samples via quantitative phase recovery. Holograms are captured on a digital camera capable of high-speed video recording of up to 2000 frames per second. The inline mode of operation can be easily configurable to a large range of magnifications. We demonstrate the efficacy of the inline mode in tracking motile bacteria in three dimensions in a 160 μm × 160 μm × 100 μm volume at 45× magnification. Through the use of a novel physical mask in a conjugate Fourier plane in the imaging path, we use our microscope for high magnification, dark field off-axis holography, demonstrated by localizing 100 nm gold nanoparticles at 225× magnification up to at least 16 μm from the imaging plane. Finally, the bright field off-axis mode facilitates quantitative phase microscopy, which we employ to measure the refractive index of a standard resolution test target and to measure the dry mass of human erythrocytes.

Prevalence of self-reported computer vision syndrome symptoms and its associated factors among university students.

To determine the prevalence of symptoms of computer vision syndrome and to identify its associated factors. The secondary objective was to assess knowledge and practices related to preventing computer vision syndrome symptoms. The data for this cross-sectional study were collected through a self-administered questionnaire distributed to 713 female undergraduates studying business and medicine in Saudi Arabia. The questionnaire included computer vision syndrome validated symptoms and factors associated with computer vision syndrome development. The most common symptom due to prolonged computer use was neck or shoulder pain, reported by 82.2% of the subjects. Overall, 66.5% of the subjects suffered from headache and 51.5% from dry eyes, in mild, moderate, or severe form. Business students were 1.6 times as likely as medical students to suffer from computer vision syndrome (odds ratio = 1.65; 95% confidence interval: 1.22, 2.24). The use of electronic devices for more than 5 h (odds ratio = 1.52; 95% confidence interval: 1.07, 2.16) was also associated with experiencing computer vision syndrome symptoms. Regarding computer vision syndrome prevention, factors such as hours of use, screen distance, screen brightness, and room illumination showed statistically significant difference between the two groups (p < 0.0001). The prevalence of computer vision syndrome symptoms was significantly higher among business students, who reported lower awareness and poor practice measures of computer use recommendations. Relevant awareness campaigns focusing on the appropriate use of computers are highly recommended.

Luminance Enhancement and Detail Preservation of Images and Videos Adapted to Ambient Illumination

When images and videos are displayed on a mobile device in bright ambient illumination, fewer details can be perceived than in the dark. The detail loss in dark areas of the images/videos is usually more severe. The reflected ambient light and the reduced sensitivity of viewer's eyes are the major factors. We propose two tone mapping operators to enhance the contrast and details in images/videos. One is content independent and thus can be applied to any image/video for the given device and the given ambient illumination. The other tone mapping operator uses simple statistics of the content. Display contrast and human visual adaptation are considered to construct the tone mapping operators. Both operators can be solved efficiently. Subjective tests and objective measurement show the improved quality achieved by the proposed methods.

Adaptive reactions of rats after light desynchronosis and physical overwork

It is known that desynchronosis and physical stress to the point of fatigue are powerful stressors for the body. Studies indicate a depleting effect of the combined stress factors on the adaptive reserves of the organism, especially when the joint exposure is prolonged. However, the adaptive value of the training process in various activities is also well known. In this regard, it seems important to study these two aspects of adaptation when combined effects of light desynchronosis and physical overwork on the body.Рurposeof this study was to study the features of adaptive reactions of rats under conditions of light desynchronosis and physical overwork.Materials and methods. An experimental study was performed on 60 mature male rats of the Wistar breed. For the induction of experimental desynchronosis, the animals of the experimental groups were kept for 10 days in artificial bright illumination (150 LX) or full darkening (2-3 LX). The model of physical overfatigue used the method of forced swimming of rats to complete fatigue in their own modification. At the end of the swim test, all the animals were withdrawn from the experiment and underwent one-step-long decapitation under CO2 with anesthesia. In decapitated animals, to collect serum, the blood was collected in a clean, dry vial. In the blood serum of rats, the biochemical standard method was used to determine the level of lactate. Using the ELISA method and the reagent kit “IBL” (Germany), the concentrations of corticosterone and serotonin were determined. The histological analysis of the stress-realizing organs was carried out according to a standard procedure using light microscopy using the Axioskop 40 microscope from CarlZeiss (Germany).Results.It was found that physical fatigue in rats after daily swimming activities (5 days) was accompanied by a decrease in the level of corticosterone in the blood serum and destructive changes in the adrenal and femoral muscles in comparison with intact animals. In comparison with the intact group, dark deprivation and physical activity did not alter the content of corticosterone, serotonin, and lactate in the blood and caused minor destructive processes in the adrenal glands. Light deprivation and fatigue lowered the level of corticosterone in the blood, caused destructive changes in the adrenal glands and muscles, and increased serotonin levels in serum, but did not change the level of lactate.Conclusions.The features of adaptive reactions of rats under conditions of light desynchronosis and physical overfatigue are determined by the nature of deprivation or the direction of the phase shift (deprivation of light or darkness). Dark deprivation followed by physical overfatigue causes the development of the resistance phase of the general adaptation syndrome, and light deprivation followed by physical overwork is the phase of exhaustion.

Usherin defects lead to early-onset retinal dysfunction in zebrafish

Mutations in USH2A are the most frequent cause of Usher syndrome and autosomal recessive nonsyndromic retinitis pigmentosa. To unravel the pathogenic mechanisms underlying USH2A-associated retinal degeneration and to evaluate future therapeutic strategies that could potentially halt the progression of this devastating disorder, an animal model is needed. The available Ush2a knock-out mouse model does not mimic the human phenotype, because it presents with only a mild and late-onset retinal degeneration. Using CRISPR/Cas9-technology, we introduced protein-truncating germline lesions into the zebrafish ush2a gene (ush2armc1: c.2337_2342delinsAC; p.Cys780GlnfsTer32 and ush2ab1245: c.15520_15523delinsTG; p.Ala5174fsTer). Homozygous mutants were viable and displayed no obvious morphological or developmental defects. Immunohistochemical analyses with antibodies recognizing the N- or C-terminal region of the ush2a-encoded protein, usherin, demonstrated complete absence of usherin in photoreceptors of ush2armc1, but presence of the ectodomain of usherin at the periciliary membrane of ush2ab1245-derived photoreceptors. Furthermore, defects of usherin led to a reduction in localization of USH2 complex members, whirlin and Adgrv1, at the photoreceptor periciliary membrane of both mutants. Significantly elevated levels of apoptotic photoreceptors could be observed in both mutants when kept under constant bright illumination for three days. Electroretinogram (ERG) recordings revealed a significant and similar decrease in both a- and b-wave amplitudes in ush2armc1 as well as ush2ab1245 larvae as compared to strain- and age-matched wild-type larvae. In conclusion, this study shows that mutant ush2a zebrafish models present with early-onset retinal dysfunction that is exacerbated by light exposure. These models provide a better understanding of the pathophysiology underlying USH2A-associated RP and a unique opportunity to evaluate future therapeutic strategies.

Possibilities for Increasing the Signal-To-Noise Ratio in Technical Vision Systems of Robotic Complexes Using Laser Structured Lighting

The development of high-resolution machine vision systems with a long observation distance is an urgent task. The possibilities to increase the observation distance by increasing the signal-to-noise ratio (SNR) based on the use of the active parallax method are discussed in the article. The achievable observation distance in such systems is determined by the brightness of the illumination source and the ratio of the brightness of the illumination source to the brightness of the background illumination (the SNR for the photodetector pixel). The goal of the investigation: The article considers the possibility of further increasing the SNR in machine vision systems with laser structured lighting due to the use of pulsed or repetitively pulsed mode of the backlight laser in combination with a time-gated photodetector. This allows to realize a machine vision system with gating, which will provide an increase in the observation distance due to the time cutoff of the background component of the recorded image. In the current scientific literature, the data on machine vision systems with temporal gating of the photodetector device are not known. Methods: To consider the possibilities of increasing the SNR in vision systems, a numerical analysis by analytical formulas was used for the parameters and the operating conditions typical for robotic technical systems. The data on the number of solar photons reflected by the object and backscattering photons arising from scattering of the both solar and laser radiation were used to calculate the SNR in machine vision systems with a conventional-type matrix photodetector and with a time-gated photodetector. Results: The calculation analysis has shown that, the using of laser illumination repetitively pulsed mode and a gated photodetector device allows to increase significantly both the SNR and the observation distance. Practical significance: The proposed technical vision system implementation can improve the characteristics of robotic systems.

An intraocular micro light-emitting diode device for endo-illumination during pars plana vitrectomy.

Development of a new, fiber-free, single-use endo-illuminator for pars plana vitrectomy as a replacement for fiber-based systems with external light sources. The hand-guided intraocularly placed white micro light-emitting diode is evaluated for its illumination properties and potential photochemical and thermal hazards. A micro light-emitting diode was used to develop a single-use intraocular illumination system. The light-source-on-tip device was implemented in a prototype with 23G trocar compatible outer diameter of 0.6 mm. The experimental testing was performed on porcine eyes. All calculations of possible photochemical and thermal hazards during the application of the intraocular micro light-emitting diode were calculated according to DIN EN ISO 15007-2: 2014. The endo-illuminator generated a homogeneous and bright illumination of the intraocular space. The color impression was physiologic and natural. Contrary to initial apprehension, the possible risk caused by inserting a light-emitting diode into the intraocular vitreous was much smaller when compared to conventional fiber-based illumination systems. The photochemical and thermal hazards allowed a continuous exposure time to the retina of at least 4.7 h. This first intraocular light source showed that a light-emitting diode can be introduced into the eye. The system can be built as single-use illumination system. This light-source-on-tip light-emitting diode-endo-illumination combines a chandelier wide-angle illumination with an adjustable endo-illuminator.

Convolutional Neural Network-Based Shadow Detection in Images Using Visible Light Camera Sensor.

Recent developments in intelligence surveillance camera systems have enabled more research on the detection, tracking, and recognition of humans. Such systems typically use visible light cameras and images, in which shadows make it difficult to detect and recognize the exact human area. Near-infrared (NIR) light cameras and thermal cameras are used to mitigate this problem. However, such instruments require a separate NIR illuminator, or are prohibitively expensive. Existing research on shadow detection in images captured by visible light cameras have utilized object and shadow color features for detection. Unfortunately, various environmental factors such as illumination change and brightness of background cause detection to be a difficult task. To overcome this problem, we propose a convolutional neural network-based shadow detection method. Experimental results with a database built from various outdoor surveillance camera environments, and from the context-aware vision using image-based active recognition (CAVIAR) open database, show that our method outperforms previous works.

Photometric stereo for three-dimensional leaf venation extraction

Leaf venation extraction studies have been strongly discouraged by considerable challenges posed by venation architectures that are complex, diverse and subtle. Additionally, unpredictable local leaf curvatures, undesirable ambient illuminations, and abnormal conditions of leaves may coexist with other complications. While leaf venation extraction has high potential for assisting with plant phenotyping, speciation and modelling, its investigations to date have been confined to colour image acquisition and processing which are commonly confounded by the aforementioned biotic and abiotic variations. To bridge the gaps in this area, we have designed a 3D imaging system for leaf venation extraction, which can overcome dark or bright ambient illumination and can allow for 3D data reconstruction in high resolution. We further propose a novel leaf venation extraction algorithm that can obtain illumination-independent surface normal features by performing Photometric Stereo reconstruction as well as local shape measures by fusing the decoupled shape index and curvedness features. In addition, this algorithm can determine venation polarity – whether veins are raised above or recessed into a leaf. Tests on both sides of different leaf species with varied venation architectures show that the proposed method is accurate in extracting the primary, secondary and even tertiary veins. It also proves to be robust against leaf diseases which can cause dramatic changes in colour. The effectiveness of this algorithm in determining venation polarity is verified by it correctly recognising raised or recessed veins in nine different experiments.

Role of recoverin in rod photoreceptor light adaptation.

Recoverin is a small molecular-weight, calcium-binding protein in rod outer segments that can modulate the rate of rhodopsin phosphorylation. We describe two additional and perhaps more important functions during photoreceptor light adaptation. Recoverin influences the rate of change of adaptation. In wild-type rods, sensitivity and response integration time adapt with similar time constants of 150-200ms. In Rv-/- rods lacking recoverin, sensitivity declines faster and integration time is already shorter and not significantly altered. During steady light exposure, rod circulating current slowly increases during a time course of tens of seconds, gradually extending the operating range of the rod. In Rv-/- rods, this mechanism is deleted, steady-state currents are already larger and rods saturate at brighter intensities. We propose that recoverin modulates spontaneous and light-activated phophodiesterase-6, the phototransduction effector enzyme, to increase sensitivity in dim light but improve responsiveness to change in brighter illumination. Recoverin is a small molecular-weight, calcium-binding protein in rod outer segments that binds to G-protein receptor kinase 1 and can alter the rate of rhodopsin phosphorylation. A change in phosphorylation should change the lifetime of light-activated rhodopsin and the gain of phototransduction, but deletion of recoverin has little effect on the sensitivity of rods either in the dark or in dim-to-moderate background light. We describe two additional functions perhaps of greater physiological significance. (i) When the ambient intensity increases, sensitivity and integration time decrease in wild-type (WT) rods with similar time constants of 150-200ms. Recoverin is part of the mechanism controlling this process because, in Rv-/- rods lacking recoverin, sensitivity declines more rapidly and integration time is already shorter and not further altered. (ii) During steady light exposure, WT rod circulating current slowly increases during a time course of tens of seconds, gradually extending the operating range of the rod. In Rv-/- rods, this mechanism is also deleted, steady-state currents are already larger and rods saturate at brighter intensities. We argue that neither (i) nor (ii) can be caused by modulation of rhodopsin phosphorylation but may instead be produced by direct modulation of phophodiesterase-6 (PDE6), the phototransduction effector enzyme. We propose that recoverin in dark-adapted rods keeps the integration time long and the spontaneous PDE6 rate relatively high to improve sensitivity. In background light, the integration time is decreased to facilitate detection of change and motion and the spontaneous PDE6 rate decreases to augment the rod working range.