Ambient Light Conditions Research Articles

Enhancing aggregation of microalgae on polystyrene microplastics by high light: Processes, drivers, and environmental risk assessment

Microplastics (MPs) are emerging pollutants, causing potential threats to aquatic ecosystems and serious concern in aggregating with microalgae (critical primary producers). When entering water bodies, MPs are expected to sink below the water surface and disperse into varying water compartments with different light intensities. However, how light influences the aggregation processes of algal cells onto MPs and the associated molecular coupling mechanisms and derivative risks remain poorly understood. Herein, we investigated the aggregation behavior between polystyrene microplastics (mPS, 10 µm) and Chlorella pyrenoidosa under low (LL, 15 μmol·m−2·s−1), normal (NL, 55 μmol·m−2·s−1), and high light (HL, 150 μmol·m−2·s−1) conditions from integrated in vivo and in silico assays. The results indicated that under LL, the mPS particles primarily existed independently, whereas under NL and HL, C. pyrenoidosa tightly bounded to mPS by secreting more protein-rich extracellular polymeric substances. Infrared spectroscopy analysis and density functional theory calculation revealed that the aggregation formation was driven by non-covalent interaction involving van der Waals force and hydrogen bond. These processes subsequently enhanced the deposition and adherence capacity of mPS and relieved its phytotoxicity. Overall, our findings advance the practical and theoretical understanding of the ecological impacts of MPs in complex aquatic environments.

Enhancing a Display’s Sunlight Readability with Tone Mapping

The sunlight readability of display devices, such as notebook computers, transparent displays, vehicle displays, and augmented reality, is a significant technical challenge due to degraded image quality. To mitigate this problem, by fitting the human eye function, we propose a tone mapping method on a mobile phone display panel to enhance low grayscale image readability under bright ambient light. Additionally, we adapt a mini-LED backlight model to simulate real images under different ambient lighting conditions. Both experimental and simulated results indicate that high luminance displays with an optimized gamma value significantly enhance sunlight readability and image quality. Moreover, global color rendering can alleviate color shift. Such a method is also valid for the optimization of optical see-through devices under diverse environmental conditions.

Comparative Study on Efficiency Analysis of Fixed and Dual-Axis Solar Tracking System

Solar energy is a crucial renewable energy source, offering sustainable solutions to address energy demands and combat climate change. Maximizing the efficiency of solar energy harvesting is essential for widespread adoption and integration into the energy landscape. Solar tracking systems play an important role in increasing the efficiency of solar panels by optimizing their orientation towards the sun throughout the day. This research presents a comparative analysis of the efficiency of dual-axis solar tracking systems using Light-Dependent Resistors (LDRs) as input devices. A closed-loop tracking technique is implemented to adjust the position of the solar panels based on real-time sensor feedback. A comparative study between LDRs demonstrates their effectiveness in detecting the sun's position, despite limitations such as susceptibility to ambient light conditions and saturation to light intensity. Through experimental evaluation and data analysis, this study provides valuable insights into the power output and assessment of efficiency variation of dual-axis solar tracking systems offering applications for optimizing solar energy harvesting in practical scenarios.

P‐115: The Optimized Method for Sparkle Contrast Measurement of Anti‐Glare Covered Vehicle Display

We have presented an optimized method for evaluating the visual sparkle contrast of anti‐glare covered vehicle display and compared the results to standard measurement conditions. By assessing the sparkle contrast changes under different ambient light conditions and different viewing angle conditions, and analyzing the results, we provide measurement recommendations for the sparkle rating evaluation of vehicle display.

P‐61: Dynamic Edge Enhancement Method

The Visteon True Color Image Enhancement system currently allows either edge detection to be activated or disabled. This study proposes a third option of implementing a dynamic edge detection method which dynamically enhances symbology edges as a function of the ambient lighting condition. Under nighttime lighting conditions, edge enhancement is not desirable since image artifacts are introduced that are not required for image visibility. As the reflected ambient lighting conditions increase, it is desirable to increase the visibility of black borders around symbology.

The Effect of Ambient Illumination and Text Color on Visual Fatigue under Negative Polarity.

This study investigates the effects of ambient illumination and negatively polarized text color on visual fatigue, exploring the issue of visual fatigue when using visual display terminals in low-illumination environments. The research methodology utilizes an experimental design to collect data on changes in pupil accommodation and blink rate through an eye tracker. Participants completed a reading task while exposed to various text colors and ambient light conditions to evaluate visual fatigue and cognitive performance. The study's findings suggest that text color significantly affects visual fatigue, with red text causing the highest level of visual fatigue and yellow text causing the lowest level of visual fatigue. Improvements in ambient lighting reduce visual fatigue, but the degree of improvement varies depending on the text color. Additionally, cognitive performance is better when using yellow and white text but worse when using red text. Yellow text is the most effective choice for reducing visual fatigue under negative polarity. Increasing ambient lighting can also improve visual fatigue in low-illumination conditions. These findings will offer valuable guidance for designing visual terminal device interfaces, especially for low-illumination or night environments, to minimize visual fatigue and improve user experience.

Engineering Graphene Phototransistors for High Dynamic Range Applications.

Phototransistors are light-sensitive devices featuring a high dynamic range, low-light detection, and mechanisms to adapt to different ambient light conditions. These features are of interest for bioinspired applications such as artificial and restored vision. In this work, we report on a graphene-based phototransistor exploiting the photogating effect that features picowatt- to microwatt-level photodetection, a dynamic range covering six orders of magnitude from 7 to 107 lux, and a responsivity of up to 4.7 × 103 A/W. The proposed device offers the highest dynamic range and lowest optical power detected compared to the state of the art in interfacial photogating and further operates air stably. These results have been achieved by a combination of multiple developments. For example, by optimizing the geometry of our devices with respect to the graphene channel aspect ratio and by introducing a semitransparent top-gate electrode, we report a factor 20-30 improvement in responsivity over unoptimized reference devices. Furthermore, we use a built-in dynamic range compression based on a partial logarithmic optical power dependence in combination with control of responsivity. These features enable adaptation to changing lighting conditions and support high dynamic range operation, similar to what is known in human visual perception. The enhanced performance of our devices therefore holds potential for bioinspired applications, such as retinal implants.

In-situ particle analysis with heterogeneous background: a machine learning approach

We propose a novel framework that combines state-of-the-art deep learning approaches with pre- and post-processing algorithms for particle detection in complex/heterogeneous backgrounds common in the manufacturing domain. Traditional methods, like size analyzers and those based on dilution, image processing, or deep learning, typically excel with homogeneous backgrounds. Yet, they often fall short in accurately detecting particles against the intricate and varied backgrounds characteristic of heterogeneous particle–substrate (HPS) interfaces in manufacturing. To address this, we've developed a flexible framework designed to detect particles in diverse environments and input types. Our modular framework hinges on model selection and AI-guided particle detection as its core, with preprocessing and postprocessing as integral components, creating a four-step process. This system is versatile, allowing for various preprocessing, AI model selections, and post-processing strategies. We demonstrate this with an entrainment-based particle delivery method, transferring various particles onto substrates that mimic the HPS interface. By altering particle and substrate properties (e.g., material type, size, roughness, shape) and process parameters (e.g., capillary number) during particle entrainment, we capture images under different ambient lighting conditions, introducing a range of HPS background complexities. In the preprocessing phase, we apply image enhancement and sharpening techniques to improve detection accuracy. Specifically, image enhancement adjusts the dynamic range and histogram, while sharpening increases contrast by combining the high pass filter output with the base image. We introduce an image classifier model (based on the type of heterogeneity), employing Transfer Learning with MobileNet as a Model Selector, to identify the most appropriate AI model (i.e., YOLO model) for analyzing each specific image, thereby enhancing detection accuracy across particle–substrate variations. Following image classification based on heterogeneity, the relevant YOLO model is employed for particle identification, with a distinct YOLO model generated for each heterogeneity type, improving overall classification performance. In the post-processing phase, domain knowledge is used to minimize false positives. Our analysis indicates that the AI-guided framework maintains consistent precision and recall across various HPS conditions, with the harmonic mean of these metrics comparable to those of individual AI model outcomes. This tool shows potential for advancing in-situ process monitoring across multiple manufacturing operations, including high-density powder-based 3D printing, powder metallurgy, extreme environment coatings, particle categorization, and semiconductor manufacturing.

Design, development and validation of a handheld colourimeter for the quantification of colourimetric assays on paper analytical devices

Colourimetric quantification of analytes on paper analytical devices (PADs) using smartphones has been gaining popularity. However, the accuracy of these devices is prone to be affected by different environmental conditions, including the intensity and colour of the ambient light. This work explains in depth the design and fabrication of a handheld colourimeter whose accuracy is unaffected by ambient light conditions using the commercially available spectral sensor AS7262. The device works on the principle of light reflection from the sample and can quantify as well as display the concentration of the analyte on an organic light-emitting-diode (OLED) display. The data acquisition, processing, and transmission of the data to a smartphone using Bluetooth in less than 7 seconds is also a salient feature. The accuracy of the device was validated by testing different concentrations of alkaline phosphatase (ALP) and total protein on PADs explicitly developed for this study. The colourimeter exhibited linearity with R² values of 0.98 for ALP and 0.97 for total protein. The LOD and LOQ obtained for ALP and total protein are 1.1, 3.89 U/L and 0.037, 0.12 g/dL, respectively. The relative standard deviation (RSD) calculated was 0.006 for ALP and 0.004 for total protein. The validation of the colourimeter was carried out with the clinical samples to obtain a relative error of less than 10 % for both the analytes.

Adaptive display white point under various ambient conditions

AbstractDisplay technologies have been developed to adjust the display brightness and color under different viewing conditions, providing better viewing experiences to users. Solutions have been proposed to adjust the display white point according to the ambient light condition, which roots into the underlying chromatic adaptation mechanism in the human visual system. This study was carefully designed to reveal the necessity to consider the ambient light level and display luminance together, which affects the viewing mode, when adjusting the adaptive display white point. The results clearly suggested that when the display luminance was greater than the ambient light diffuse white luminance, the display was viewed in the self‐luminous mode and the display white point was not significantly affected by the ambient light chromaticities. In contrast, when the display luminance was lower than the ambient light diffuse white luminance, the display was viewed in the surface mode and the ambient light chromaticities had a significant effect on the display white point, especially when the surround ratio was high.

Optimization of crystal violet technique for enhanced fingerprint detection on various surfaces.

The crystal violet (CV) staining technique represents a prevalent approach for the development of latent fingerprints, especially on adhesive tape surfaces. Nevertheless, the technique necessitates intricate formulations to augment its performance. In this investigation, an optimized CV staining protocol was developed, characterized by the absence of residual dye on the target substrates and the capability of facilitating fingerprint visualization under ambient light conditions. Four donors, comprising two males and two females, deposited natural fingerprints on various substrates, including glass microscope slides, aluminum foil, and 115 g glossy coated paper, without any specific guidelines. Fingerprints developed using cyanoacrylate fuming served as benchmarks and were contrasted with those generated through alternative methods: CV, ardrox, rhodamine 6G, powdering, and the optimized CV staining protocol. The fingerprint development experiment was replicated at seven distinct time intervals, encompassing 1 day, 1 week, 1, 3, 6, 9, and 12 months, resulting in a dataset of 420 fingerprints. The evaluation of fingerprint identifiability employed a scoring system established by the Home Office Centre for Applied Science and Technology. The results indicated that the optimized CV staining technique demonstrated superior performance, boasting a 92.9% rate of identifiable fingerprint development in contrast to other employed methodologies. Consequently, this optimized CV staining approach is recommended as an efficient, rapid, and straightforward critical dyeing method, applicable to a wide array of substrates in forensic investigations.

First Report of Globisporangium (Pythium) mastophorum causing Damping-off / Root Rot on Parsley in Slovenia.

Pythium-like species cause damping-off symptoms of various hosts, including umbelliferous crops. In April 2023, parsley plantlets (Petroselinum crispum), showing stunted growth, yellowing, decayed roots and damping-off, were obtained from a nursery in central Slovenia, where parsley was grown in polystyrene trays in a greenhouse. Nearly 30% of plants were symptomatic. Sampled roots of ten plants contained ornamented oogonia (avg. 33.3 ± 1.4 µm in diam) with conical projections (5.2 ± 0.5 µm long) (Figure S1 A, B) in microscopically analyzed squash mounts. The pathogen was isolated from root pieces treated for surface disinfection with 0.5% sodium hypochlorite for 30 s, and washed with sterile water. Four 1-2 mm root pieces were taken from each of 10 plants, plated on the selective medium P5ARP, and incubated at 21 °C. Mycelia emerging from root pieces were transferred to carrot piece agar (CPA). Twenty-two equally looking oomycetous colonies were obtained; all sampled plants were infested. Oogonia formed by all colonies were similar to those observed on decayed roots and suggested that Globisporangium (Pythium) mastophorum is the causal disease agent. Analyses of partial β-tubulin (Kroon et al. 2004) and mitochondrial cytochrome c oxidase I (COI) gene sequences (Robideau et al. 2011) confirmed the identification. Obtained COI (Genbank accession number OR725417) sequence was 100% identical to that from G. mastophorum strain CBS 375.72 (EU350523), whereas the β-tubulin sequence (OR725416) corresponded to 99.6 % pairwise identity (KJ595502). Further, pathogenicity of an obtained isolate was tested on 4 wk-old curly leaf (cv. Petra F1) parsley. Half of a 7 d-old CPA culture, consisting of mycelium and oogonia, was finely cut and mixed with ca 50 ml of nonsterile commercial substrate (Potgrond H, AGRO-FertiCrop) in each of six 400 ml pots. Pots were filled with ca 300 ml additional substrate, into which 5 parsley seedlings were planted. Control plants were treated equally but with sterile CPA. Plantlets were watered with sterile tap water and held at ambient light conditions and temperature (night 18 °C - day 23 °C). After 14 d, inoculated plants started wilting and yellowing and showed stunted growth. After 21 d, roots were severely decayed and the seedlings damped-off (Figure S1 C). Four pieces each from 10 decayed roots were plated. Thirty-one pieces revealed pythium-like colonies. Obtained isolates were morphologically identical to the strain used for inoculation and identified as G. mastophorum. Control plants developed no foliar or root symptoms and no pythium-like species was obtained. Agricultural advisors observed occurrence of parsley damping-off also in other nurseries in Slovenia what may lead to spreading the pathogen to parsley in production fields and private gardens. The case emphasizes the need for implementing phytosanitary measures in order to eliminate primary inoculum. Reports from field-infected plants showed that G. mastophorum is a pathogen of parsley in Australia (Petkowski et al. 2013) and the USA (Tsuchida et al. 2018), and celery in the Czech Republic (Šafránková and Holková 2017). Others isolated G. mastophorum from parsley in The Netherlands (online database of the Westerdijk Fungal Biodiversity Institute, strain CBS 243.86). However, the here described case is, to the best of our knowledge, one of the rare documentations of damping-off due to G. mastophorum in Europe (Šafránková and Holková 2017) and the first in Slovenia. Funding: The work was funded by the Ministry of Agriculture, Forestry and Food of Slovenia, and Slovenian Research and Innovation Agency (ARIS Programs P4-0431 and P4-0072).

Investigating the timing of spawning of two sea urchins (Tripneustes gratilla and Toxopneustes pileolus)

AbstractMany marine organisms broadcast gametes for external fertilization, thus conspecifics need to concentrate the time of gamete release through synchronization with environmental factors. We investigated the timing of spawning in two sea urchin species, Tripneustes gratilla and Toxopneustes pileolus, by assessing the spawning potential of individuals using both surveys and experiments in southern Taiwan from March to November 2010. We developed a new method to observe the spawning potential without sacrificing any individuals, defining those individuals‐initiated spawning within 30 min after 10 s of exposure to air as having the spawning potential. We discovered that the percentage of individuals with spawning potential, that is, the spawning ratios of the population, varied greatly from 0% to 80% in To. pileolus and from 0% to 50% in Tr. gratilla within the reproductive seasons. We evaluated the possibility of a lunar/semilunar rhythm of spawning ratios of the population and tested three environmental factors, that is, light intensity, tide, and temperature that could potentially affect the spawning potential of the sea urchins by experiments. Individuals with spawning potential were neither randomly nor evenly distributed among days but were aggregated on certain days; however, no lunar/semilunar rhythm of the spawning ratios was detected within the reproductive season. The possible role of the tidal factor within a day was not found in experiments in either species. However, when water temperature was >27°C in our surveys, significantly higher spawning ratios were observed in To. pileolus, but not in Tr. gratilla in the reproductive season. A further temperature experiment in To. pileolus supported the positive role of high temperature on the spawning ratios of individuals. In addition, To. pileolus was more likely to spawn during the day than at night, and the light/dark experiments suggested that the spawning potential was controlled by an endogenous biological clock rather than by the ambient light conditions directly. The lack of rhythmic pattern and yet concentrated spawning of these sea urchins may be adaptive to avoid predation.

Investigating the effect of ambient light conditions on road traffic crashes: The case of Cape Town, South Africa

Investigating the risk of road crashes associated with ambient light is often challenged by bias resulting from confounding effects of other risk factors. The study used the odds ratio and the risk ratio methods to isolate the effect of ambient light from other risk factors. This was possible in this research using the ‘whole-year’ approach adopted in previous research and utilising seasonal variations in ambient light in Cape Town. The analysis was based on crash and ambient light data collected between 2014 and 2018 in Cape Town. A total of 361 452 crashes were reported during this period. With only minor exceptions, the results confirm a higher crash risk in both twilight and dark conditions. The increase in the risk was different depending on the ambient light level, the crash type (total and pedestrian crashes) and the time of the day (morning and evening times). The results suggest that more efforts need to be made to assist road users to travel safely under twilight and dark conditions.

An Investigation of a Biomimetic Optical System and an Evaluation Model for the Qualitative Analysis of Laser Interference Visual Levels.

To objectively quantify the level of visual interference induced by lasers, we developed a biomimetic optical system designed to emulate human vision. This system is based on an optical model of the eye and synthetic imaging principles, allowing it to generate biomimetic optical images that closely mimic human visual perception. Upon exposure to a 532 nm laser, biomimetic optical images were captured under various ambient lighting conditions. By employing a contrast threshold model for human visual target detection and grayscale hierarchy analysis, we devised an evaluation model to quantify the levels of laser-induced visual interference. The bionic images obtained from our experiments, in conjunction with the constructed model, enabled us to assess the degree of laser-induced visual interference. Our results indicate that this system can effectively substitute the human eye when testing laser imaging effects, with the generated bionic images achieving up to 90% concordance with human vision. The proposed evaluation model facilitates the quantitative analysis of laser-induced visual impairment. This apparatus and evaluation model hold significant promise for the precise quantification of laser-induced visual interference levels.

Intelligent Lighting System Using Color-Based Image Processing for Object Detection in Robotic Handling Applications

In applications reliant on image processing, the management of lighting holds significance for both precise object detection and efficient energy utilization. Conventionally, lighting control involves manual switching, timed activation or automated adjustment based on illuminance sensor readings. This research introduces an embedded system employing image processing methodologies for intelligent ambient lighting, focusing specifically on reference-color-based illumination for object detection and positioning within robotic handling scenarios. Evaluating the system’s efficacy entails analyzing the illuminance levels and power consumption through a tailored experimental setup. To minimize illuminance, the LED-based lighting system, controlled via pulse-width modulation (PWM), is calibrated using predetermined red, green, blue and yellow (RGBY) reference objects, obviating the need for external sensors. Experimental findings underscore the significance of color choice in detection accuracy, highlighting yellow as the optimal color requiring minimal illumination. Successful object detection based on color is demonstrated at an illuminance level of approximately 50 lx, accompanied by energy savings contingent upon ambient lighting conditions.

IOT based smart street light fault detection management system

In the contemporary landscape of urbanization and technological progress, efficient resource management, particularly in energy consumption, is paramount. Street lighting stands out as a significant energy consumer in urban environments. This paper proposes a Smart Street Light Fault Detection System utilizing Internet of Things (IoT) technology, a NodeMCU microcontroller, Light Dependent Resistor (LDR), street lights, and the ThingSpeak. The system employs the NodeMCU microcontroller to monitor ambient light conditions through the LDR sensor, enabling automatic control of street lights to optimize energy usage. Furthermore, it integrates fault detection mechanisms to identify abnormalities in street light operations, such as constant light levels amidst changing environmental conditions, indicative of potential faults. Through the ThingSpeak, users can remotely monitor real-time LDR readings, receive notifications about detected faults, and take necessary actions, empowering city authorities or maintenance personnel with timely information for addressing issues and ensuring smooth infrastructure operation. This smart system offers advantages like energy efficiency, automated control, and proactive fault detection, facilitating significant energy savings, reduced maintenance costs, and enhanced sustainability in urban environments, thereby showcasing a practical implementation of IoT technology for smarter and more sustainable cities.

Broadband nonlinear modulation of incoherent light using a transparent optoelectronic neuron array

Nonlinear optical processing of ambient natural light is highly desired for computational imaging and sensing. Strong optical nonlinear response under weak broadband incoherent light is essential for this purpose. By merging 2D transparent phototransistors (TPTs) with liquid crystal (LC) modulators, we create an optoelectronic neuron array that allows self-amplitude modulation of spatially incoherent light, achieving a large nonlinear contrast over a broad spectrum at orders-of-magnitude lower intensity than achievable in most optical nonlinear materials. We fabricated a 10,000-pixel array of optoelectronic neurons, and experimentally demonstrated an intelligent imaging system that instantly attenuates intense glares while retaining the weaker-intensity objects captured by a cellphone camera. This intelligent glare-reduction is important for various imaging applications, including autonomous driving, machine vision, and security cameras. The rapid nonlinear processing of incoherent broadband light might also find applications in optical computing, where nonlinear activation functions for ambient light conditions are highly sought.

Biological control of selected weeds of direct-seeded rice through application of allelopathic Pseudomonas strains

ABSTRACT Weeds are a major obstacle in the widespread implementation of direct seeding of rice (DSR). Traditional weed control methods have raised serious environmental and health concerns. In this study rhizobacterial strains were assessed for the growth inhibition of Leptochloa chinensis, Dactyloctenium aegyptium, and promotion of rice. For initial screening, hydrogen cyanide (HCN) and Escherichia coli (E. coli) was employed. After screening, plant growth-promoting traits were assessed, and two in vitro growth reduction and growth promotion trials were conducted on weeds and rice. Based on 16S ribosomal RNA (16S rRNA) gene sequencing, all selected rhizobacteria belonged to Pseudomonas spp. The results of the laboratory experiment showed that strains R4-1 (Pseudomonas plecoglossicida) and R16-10 (Pseudomonas fluorescens) exhibited significant ability to inhibit the growth of selected weeds, while potential to enhance the growth of rice. Further evaluation in pot trial under ambient light and temperature conditions showed that the selected strains significantly reduced weed growth and yield parameters of both weeds compared to the control. Strains R16-10 and R4-1 decreased the biomass of Leptochloa chinensis and Dactyloctenium aegyptium by 20% and 15%, respectively. The trial confirmed that strain R16-10 significantly increased DSR growth traits infested with Leptochloa chinensis and Dactyloctenium aegyptium, including grain yield (10% and 12%) and photosynthetic rate (9% and 7%). Furthermore, strain R4-1 was also effective in promoting the growth, yield, and physiological attributes of DSR. These results suggest that the strain R16-10 and R4-1 can reduce Leptochloa chinensis and Dactyloctenium aegyptium growth while promoting DSR growth.

Enhancing legibility in educational settings: Optimizing projection illuminance for varied indoor ambient illuminance

Projectors are common display devices in the educational setting. However, dim projector lightbulbs or well-lit classrooms may cause blurriness in the projected image. To determine the optimal projection light under different ambient light conditions, the conjoint effects of projection illuminance and ambient illuminance on the legibility of projection images indoors were investigated. Participants (N = 96) were randomly assigned to one of six indoor ambient light conditions (0, 40, 80, 120, 160, and 200 lx) and performed a visual search task under several projection illuminance conditions (200, 250, 300, 350, and 400 lx). The accuracy and correct response time on the task were collected to evaluate the participants’ visual performance to represent legibility. The optimal projection illuminance (high visual accuracy and fast reaction) was 400 lx (944 ANSI lumen) under all ambient light conditions. To avoid low legibility (accuracy<0.6) and maintain acceptable legibility (accuracy>0.7), the projection illuminance should be increased as the indoor ambient light increases.