Illumination Design Research Articles

Design and Application Research of a UAV-Based Road Illuminance Measurement System

This paper presents a UAV-based road illumination measurement system and evaluates its performance through experiments. The system employs a HUBSAN Zino 2+ UAV, STM32F103RCT6 microcontroller, BH1750 illuminance sensor, and GPS and integrates flight, processing, measurement, cloud platform, obstacle avoidance, communication, and power supply units via the OneNET cloud platform. Both hardware and software designs were implemented, using the Z-score algorithm to handle outliers in illumination data. The system showed a single-point measurement error rate of 1.14% and a MAPE of 5.08% for multi-point measurements. In experiments, the system’s horizontal and vertical illuminance RMSE were 1.92 lx and 1.75 lx, respectively. The real-time visualization interface improved operational efficiency, cutting labor costs by half and time costs by nearly four-fifths. UAV control and monitoring from the roadside ensured safety during measurements. The system’s efficiency and wide measurement range enabled extended experiments, collecting illuminance data across multiple horizontal and vertical planes. This resulted in the creation of both horizontal and innovative vertical-plane illuminance distribution maps. These findings provide valuable data for evaluating road lighting quality, enhancing road traffic safety, and improving road illumination design.

Challenges in illumination analysis and design for Martian surface-level habitation

It is needless to say that travel to and settlement on Mars are associated with extreme levels of scientific and engineering issues. This will only be amplified with the long-term duration of the mission, not only due to scarcity of resources, but also as the psychological aspects of the dynamics among the crew increase drastically. It should be emphasized that this is a scientific crew, who have undergone high levels of confinement during space travel to Mars, O (102 Earth days), are living in semi-solitude and partial confinement conditions for durations of O (103 Earth days), and even at the nominal termination of the mission, foresee a high-risk and arduous travel time of O (102 Earth days) back to the Earth. The mental weight of the described mission with its slow pace and tardy episodes, puts the crew under severe psychological issues. Minimal and conservative design of spaces, lack of constant access to the exterior, and social solitude are among major factors contributing to the psychological well-being of the crew. Furthermore, the overall lower levels of natural light, accompanied by the minimum possible area of transparent facades, protecting the crew from harmful radiations and cold exterior, burden the mental conditions of the crew even more. Given the limited availability of data from the surface of Mars, study of the effects linked to the lighting and illumination design of the habitats is challenging. The current manuscript hopes to shed light on the illumination and lighting design and simulation procedure, required data, assumptions, and final results for the surface-level habitats on Mars.•Mars / Sub orbital configuration allows for limited natural lighting, however, upon site-specific analysis, it might be considerable as a base passive source.•Current simulation tools are design based on Earth-bound design requirements. These need to be re-oriented to match available planetary data.

Optical design of low-location illumination based on asymmetric double freeform surfaces.

The development of optical optics for low-location road lighting is a challenging problem in providing high luminance and uniformity of illumination and meeting many other specific requirements. This study proposes an optical design method of low-location illumination based on an asymmetric double freeform surface lens. The ray emitted from the light source is refracted and reflected through the different surface types to the corresponding area of the receiving surface. In the design example, the road has dual-side mounted luminaires and a width of 6m, and a height of 0.8m. Simulation results indicate that, compared with conventional high-pole streetlights, the luminance uniformity had increased from 0.60 to 0.66, the illuminance uniformity had improved from 0.75 to 0.86, and the glare had been reduced.

Holographic Imaging With XL-MIMO and RIS: Illumination and Reflection Design

Holographic Imaging With XL-MIMO and RIS: Illumination and Reflection Design

InGaN blue resonant cavity micro-LED with RGY quantum dot layer for broad gamut, efficient displays

The technology of RGBY micro resonant cavity light emitting diodes (micro-RCLEDs) based on quantum dots (QDs) is considered one of the most promising approaches for full-color displays. In this work, we propose a novel structure combining a high color conversion efficiency (CCE) QD photoresist (QDPR) color conversion layer (CCL) with blue light micro RCLEDs, incorporating an ultra-thin yellow color filter. The additional TiO2 particles inside the QDPR CCL can scatter light and disperse QDs, thus reducing the self-aggregation phenomenon and enhancing the eventual illumination uniformity. Considering the blue light leakage, the influences of adding different color filters are investigated by illumination design software. Finally, the introduction of low-temperature atomic layer deposition (ALD) passivation protection technology at the top of the CCL can enhance the device's reliability. The introduction of RGBY four-color subpixels provides a viable path for developing low-energy consumption, high uniformity, and efficient color conversion displays.

IMPROVING THE AUTOMATED APPROACH TO CALCULATING AND ASSESSING THE STATE OF NATURAL ILLUMINATION

Problem statement. In the XXI century, there is a global trend towards the development of specialised software that would solve a number of specific problems within certain subject areas. The task of extending the functionality of the developed software for calculating side illumination with functionality that would allow the calculation of overhead natural illumination is becoming increasingly important. The purpose of the article is to improve the automated approach to calculating the regulated area of light openings in buildings and structures, as well as assessing the available natural illumination by filling the developed software for assessing side natural illumination with functionality for assessing overhead natural illumination. Conclusions. The developed software product for the calculation of one-sided side natural illumination was supplemented with functionality designed to calculate two-sided side lighting and overhead natural illumination. It provides protection against entering erroneous data, and partially implements automated document flow, which includes the ability to keep a log of calculations. The use of such specialized software is one of the methods of automating calculations in the preliminary design of natural illumination of premises, as well as in assessing the existing natural illumination and its compliance with the requirements regulated by DBN B.2.5:28-2018 Natural and artificial illumination. The proposed method for calculating natural illumination will minimize the possibility of errors, increase the accuracy of the calculations, speed up the process of calculating the area of illumination openings, and allow the calculation of the area of illumination openings without knowledge of the methodology. This method is of practical use in the construction industry when designing illumination systems, as well as in the field of occupational health and safety to assess the compliance of existing illumination with the regulated requirements.

Analysis of drivers’ mental workload in V-shaped undersea tunnels based on heart rate variability

To explore the effects of illumination and tunnel longitudinal slope on driving safety in V-shaped undersea tunnels, we conducted a study to analyze changes in drivers’ mental workload caused by Illumination and longitudinal slope variations within the tunnel through field data. The typical V-shaped undersea tunnel crossing Jiaozhou Bay in Qingdao, China, was selected. Thirty drivers were recruited to participate in the driving tests during off-peak hours and 120 sets of electrocardiographic (ECG) signals were collected from drivers under natural driving conditions. The standard deviation of the Normal-to-Normal intervals (SDNN) was used and an outlier test was performed using the box plot. The drivers’ SDNN was used to index drivers’ mental workload under different Illumination and longitudinal slope conditions in the V-shaped undersea tunnel. A model was established to quantify the relationships of illumination and longitudinal slope with the SDNN. The results showed a significant negative correlation between the illumination change rate and the SDNN, i.e., the greater the change rate of illumination was, the smaller the SDNN was (and the greater the mental workload was). While the mental workload of drivers varied on tunnel longitudinal slope compared with illumination. With increased steepness of longitudinal slopes, the driver’s SDNN value decreased, but the SDNN of drivers in the downhill section were smaller than SDNN in the uphill section, reflecting a greater mental workload. Finally, a proposed value interval for the combined design of illumination and slope in undersea tunnels is given in the context of drivers’ mental workload variations.

High-resolution display screen as programmable illumination for Fourier ptychography

We introduce a new programmable illumination strategy for Fourier ptychographic microscopy (FPM), utilizing a high-resolution organic light-emitting diode (OLED) display screen at the vicinity of the sample to achieve super-resolution and quantitative phase imaging of biological samples. High-density pixels in the OLED screen allow for the angle-scanning illumination required for FP by placing the sample slide directly on the screen, where multiple images of the sample are captured while scanning the pixels on the screen. We discuss the design of the OLED-FP illumination and the corresponding image reconstruction strategies and experimentally validate the super-resolution and phase imaging capabilities of FP using a smartphone screen as illumination. Further, we extend our method to patterned illumination strategies, which multiplexes multiple illumination pixels to achieve full-field FP imaging with a reduced number of measurements, where we identify an optimal illumination pattern and density to maximize the imaging speed without sacrificing the image quality. Our approach offers a simple and compact programmable illuminator that can effectively transform any microscope into a compact FPM with resolution improvement and phase imaging capabilities.

Freeform surface topology prediction for prescribed illumination via semi-supervised learning.

Despite significant advances in the field of freeform optical design, there still remain various unsolved problems. One of these is the design of smooth, shallow freeform topologies, consisting of multiple convex, concave and saddle shaped regions, in order to generate a prescribed illumination pattern. Such freeform topologies are relevant in the context of glare-free illumination and thin, refractive beam shaping elements. Machine learning techniques already proved to be extremely valuable in solving complex inverse problems in optics and photonics, but their application to freeform optical design is mostly limited to imaging optics. This paper presents a rapid, standalone framework for the prediction of freeform surface topologies that generate a prescribed irradiance distribution, from a predefined light source. The framework employs a 2D convolutional neural network to model the relationship between the prescribed target irradiance and required freeform topology. This network is trained on the loss between the obtained irradiance and input irradiance, using a second network that replaces Monte-Carlo raytracing from source to target. This semi-supervised learning approach proves to be superior compared to a supervised learning approach using ground truth freeform topology/irradiance pairs; a fact that is connected to the observation that multiple freeform topologies can yield similar irradiance patterns. The resulting network is able to rapidly predict smooth freeform topologies that generate arbitrary irradiance patterns, and could serve as an inspiration for applying machine learning to other open problems in freeform illumination design.

LED Arrays Design for Large Area and High Uniform Illumination

LED Arrays Design for Large Area and High Uniform Illumination

Ptychographic lens-less birefringence microscopy using a mask-modulated polarization image sensor

Birefringence, an inherent characteristic of optically anisotropic materials, is widely utilized in various imaging applications ranging from material characterizations to clinical diagnosis. Polarized light microscopy enables high-resolution, high-contrast imaging of optically anisotropic specimens, but it is associated with mechanical rotations of polarizer/analyzer and relatively complex optical designs. Here, we present a form of lens-less polarization-sensitive microscopy capable of complex and birefringence imaging of transparent objects without an optical lens and any moving parts. Our method exploits an optical mask-modulated polarization image sensor and single-input-state LED illumination design to obtain complex and birefringence images of the object via ptychographic phase retrieval. Using a camera with a pixel size of 3.45 μm, the method achieves birefringence imaging with a half-pitch resolution of 2.46 μm over a 59.74 mm2 field-of-view, which corresponds to a space-bandwidth product of 9.9 megapixels. We demonstrate the high-resolution, large-area, phase and birefringence imaging capability of our method by presenting the phase and birefringence images of various anisotropic objects, including a monosodium urate crystal, and excised mouse eye and heart tissues.

Design of freeform phase diffractive optical elements based on the quadratic assignment problem.

The design of freeform phase diffractive optical elements is a challenging task, typically necessitating the use of complex differential equations or a large number of iterative calculations. This paper proposes what we believe to be a novel approach to address this problem. In this strategy, we introduce overall comparison optimization (OCO) to ensure the fast convergence of the cost function. The quadratic assignment problem (QAP) is used as the mathematical framework for designing freeform phase diffraction optics. Specifically, the ray mapping calculation problem in geometric optics is simplified as a QAP. To solve this problem, we apply the OCO method, which ensures that the cost function rapidly progresses in the "non-negative" direction, thereby facilitating fast convergence in each optimization iteration. In this manner, the proposed approach alleviates the computational burden associated with repeated evaluations of the cost function and accelerates convergence in the design process. We construct holographic masks using the OCO method and perform simulations to demonstrate the potential of the proposed method in swiftly realizing complex illumination patterns. The results show that the design model has good performance when dealing with complex illumination tasks. The conclusions obtained in this paper can be extended to the realization of phase-only holography and the solution of freeform surfaces illumination design.

Gradient descent-based freeform optics design for illumination using algorithmic differentiable non-sequential ray tracing

Algorithmic differentiable ray tracing is a new paradigm that allows one to solve the forward problem of how light propagates through an optical system while obtaining gradients of the simulation results with respect to parameters specifying the optical system. Specifically, the use of algorithmically differentiable non-sequential ray tracing provides an opportunity in the field of illumination engineering to design complex optical system. We demonstrate its potential by designing freeform lenses that project a prescribed irradiance distribution onto a plane. The challenge consists in finding a suitable surface geometry of the lens so that the light emitted by a light source is redistributed into a desired irradiance distribution. We discuss the crucial steps allowing the non-sequential ray tracer to be differentiable. The obtained gradients are used to optimize the geometry of the freeform, and we investigate the effectiveness of adding a multi-layer perceptron neural network to the optimization that outputs parameters defining the freeform lens. Lenses are designed for various sources such as collimated beams or point sources, and finally, a grid of point sources approximating an extended source. The obtained lens designs are finally validated using the commercial non-sequential ray tracer LightTools.

Impact of Street Lighting Level on Floodlights

The article presents selected results of research related to the use of outdoor lighting, mainly street lighting, in the design of facility illumination. The indicated subject matter primarily concerns architectural structures that are located in urbanized city spaces and in the strict centers of old cities. It is in these areas that there is usually a significant saturation of historic secular and sacred buildings with significant tourist values. At the same time, the immediate surroundings of the structures are usually wrapped by a dense network of street lighting infrastructure. This illumination can be a major setback in the process of illumination planning. Therefore, it is necessary to take into account the extent of this impact on the planned illumination work, related to the selection, mounting, and direction of illumination equipment. This is related to the distance of the street luminaires from the facade, the height of their installation, the distance of the poles from each other, the power of the street luminaires, and the luminous flux distribution of the luminaires used. The purpose of the work undertaken was to analyze the extent to which outdoor lighting influences the planned illumination of an architectural structure and to explore the possibility of its potential use as a component of illumination. Analytical work was conducted at two levels of detail using advanced graphical computer applications. After general considerations and the derivation of conclusions, an example of illumination of a large sacral building was realized successfully using the element of street lighting as a component of illumination.

Design of illumination system using characterized illuminances for smartphone-based fundus camera

Recently, smartphone-based fundus camera (SBFC) research has been actively conducted in response to the need to expand medical infrastructure in underdeveloped countries and the increased telemedicine since the COVID-19 pandemic. Compared to the conventional table-top system, SBFCs have technical challenges that make it difficult to guarantee uniform illumination and avoid back-reflection because of the design constraints of minimizing the form factor and cost. This paper proposes a novel illumination design methodology using characterized illuminance to obtain high-quality fundus images for SBFCs. Key performance indicators (KPIs), such as retinal uniformity, back-reflection suppression, and optical efficiency, were defined to evaluate the performance of the illumination system. Each KPI was calculated using optical simulation software based on Monte-Carlo ray tracing and mapped into a normalized three-dimensional coordinate, the retinal illumination performance space (RIPS). In RIPS, the KPIs are combined into a single parameter ΔRIPS, which is the quantitative difference evaluated as the Euclidean distance between the ideal and actual design point. A compact SBFC illumination system with five design variables was presented to verify the proposed methodology. The final design values at the minimum ΔRIPS were determined using the Taguchi method and response surface methodology. Finally, a working prototype was built, and fundus images were acquired by clinical testing under institutional review board approval. The fundus image had sufficient brightness and resolution to diagnose the lesion with a viewing angle of approximately 50° in one shot.

Design and Implementation of Solar-Powered Optical Fiber-Based Illumination and Communication System for Underground Coal Mines

Design and Implementation of Solar-Powered Optical Fiber-Based Illumination and Communication System for Underground Coal Mines

The Next Generation of Beam Hopping Satellite Systems: Dynamic Beam Illumination With Selective Precoding

Beam Hopping (BH) is a popular technique considered for next-generation multi-beam satellite communication system which allows a satellite focusing its resources on where they are needed by selectively illuminating beams. While beam illumination plan can be adjusted according to its needs, the main limitation of convectional BH is the adjacent beam avoidance requirement needed to maintain acceptable levels of interference. With the recent maturity of precoding technique, a natural way forward is to consider a dynamic beam illumination scheme with selective precoding, where large areas with high-demand can be covered by multiple active precoded beams. In this paper, we mathematically model such beam illumination design problem employing an interference-based penalty function whose goal is to avoid precoding whenever possible subject to beam demand satisfaction constraints. The problem can be written as a binary quadratic programming (BQP). Next, two convexification frameworks are considered namely: (i) A Semi-Definition Programming (SDP) approach particularly targeting BQP type of problems, and (ii) Multiplier Penalty and Majorization-Minimization (MPMM) based method which guarantees to converge to a local optimum. Finally, a greedy algorithm is proposed to alleviate complexity with minimal impact on the final performance. Supporting results based on numerical simulations show that the proposed schemes outperform the relevant benchmarks in terms of demand matching performance while minimizing the use of precoding.

Road marking BRDF model applicable for a wide range of incident illumination conditions.

To drive safely and comfortably, an adequate contrast between the road surface and road markings is needed. This contrast can be improved by using optimized road illumination designs and luminaires with dedicated luminous intensity distributions, taking advantage of the (retro)reflective characteristics of the road surface and road markings. Since little is known about road markings' (retro)reflective characteristics for the incident and viewing angles relevant for street luminaires, bidirectional reflectance distribution function (BRDF)-values of some retroreflective materials are measured for a wide range of illumination and viewing angles using a luminance camera in a commercial near-field goniophotometer setup. The experimental data are fitted to a new and optimized "RetroPhong" model, which shows good agreement with the data [root mean squared error (R M S E)<0.13, normalized root mean squared error (N R M S E)<0.04, and the normalized cross correlation ratio (N C C)>0.8]. The RetroPhong model is benchmarked with other relevant (retro)reflective BRDF models, and the results suggest that the RetroPhong model is most suitable for the current set of samples and measurement conditions.

State-of-the-Art Capabilities of Computer Graphics in Museum Lighting Modelling

Computer graphics and technologies have currently come a long way from engineering methods of environment and space parameter calculation. In the spheres of light engineering and lighting design, it is time to switch to modelling of illumination using mainly graphic lighting effects and imagery rather than digital values. Such transfer is impossible without trying to form the methodology and recommendations for 3D modelling of illumination. The authors of this article attempt to describe the key approaches to 3D modelling of museum illumination using contemporary software. The operating lighting installation of one of the halls of the Pushkin State Museum of Fine Arts is used as an example. Based on the achieved results of the research, we tried to describe the methodology and to provide recommendations for quality design and modelling of illumination in any exhibition spaces. The described methodology may be useful both for lighting engineers, architects, designers, and for curators and museum employees. The former may use the methodology for technical approach and implementation of museum illumination while the latter may use it to find a common language with the former and to compile more accurate terms of reference for them.

Redesain Dan Tradisi Visualisasi Dalam Iluminasi Naskah Melayu Nusantara

This paper study aims to unravel the existence of the visualization tradition of Malay society in the illumination of Malay texts in the archipelago and to detect the redesign of the legacy of illumination in the interests of today's society. The method used in this study uses a qualitative research method with a literature study approach that uses primary and secondary data sources that are searched by literature data collection techniques from various sources and then analyzed with the needs of researchers for the data presented in this study. In this study several conclusions can be drawn, the visualization tradition in the illumination of Malay archipelago manuscripts is a reflection of the intellectuality of the written tradition which is an indicator of cultural phenomena in the form of ideas, social system and practices. Then, the main element that always exists in Malay texts in the archipelago is bamboo shoots which have a philosophy to continue to grow tall, strong and strong from the wind. Second, the redesign of the Malay script illumination visualization tradition still occurs today, especially in the interests of socio-economic welfare for the creative industry as contained in the revitalization of the illumination design into a digital vector shape which helps make it easy to apply in various design formats for invitations, paintings, book cover frames, paintings. , and batiks. One that has materialized is to become batik cloth in various Malay regions. Seeing these conditions, the Malay Archipelago script has a great opportunity to be redesigned in the current context. This, in addition to preserving the Malay manuscript illumination visualization tradition through a distinctive representation of meaning, is a very valuable cultural heritage.