Illumination System Research Articles

Sensor simulation using a spectrum tunable LED system.

This study developed a method to simulate the sensor responses and verify the effectiveness on spectral reconstruction by a spectrum tunable LED system. Studies have shown that the spectral reconstruction accuracy could be improved by including multiple channels in a digital camera. However, the real sensors with designed spectral sensitivities were hard to manufacture and validate. Therefore, the presence of a quick and reliable validation mechanism was preferred when performing evaluation. In this study, two novel approaches, i.e., channel-first and illumination-first simulations, were proposed to replicate the designed sensors with the use of a monochrome camera and a spectrum-tunable LED illumination system. In the channel-first method, the spectral sensitivities of three extra sensor channels were optimized theoretically for an RGB camera and then simulated by matching the corresponding illuminants in the LED system. The illumination-first method optimized the spectral power distribution (SPD) of the lights using the LED system, and the extra channels could be determined accordingly. The results of practical experiments showed that the proposed methods were effective to simulate the responses of the extra sensor channels.

Influence of Lightpipes on Readers for Microtubes Fluorescence Detection

Lightpipes are light guides based on total internal reflection used for LED illumination systems with many applications. This work investigates using lightpipes in a fluorescent reader for microtubes. It is part of a project to develop an RT-RPA multiplex test and fluorescence reader for SARS-COV 2 and H1N1. We investigated the lightpipes interaction with an excitation filter. The results do not show a benefit in using them on the emission side due to the capture of LED scattered light.

Dithered single-objective light sheet for improved super-resolution imaging throughout mammalian cells.

Single-molecule super-resolution fluorescence microscopy is a powerful method for imaging detailed biological structures at the nanoscale. However, imaging single molecules precisely in thick samples such as mammalian cells is notoriously difficult due to increased fluorescence background. Light sheet fluorescence microscopy in which the sample is illuminated with a thin plane of light mitigates the problem of increased fluorescence background in thick samples and results in increased signal-to-background ratio and improved localization precision. However, light sheet illumination is sensitive to shadowing artifacts from imperfections in the optical path and scattering throughout the sample. Additionally, most light sheet systems employ two objectives, which may suffer from steric hindrance and drift between the sample and illumination objective. To overcome these disadvantages, we have developed a single-objective tilted light sheet illumination system which employs dithering to reduce stripe artifacts and achieve homogeneous illumination of the sample. Our light sheet has been designed with a width, thickness, and confocal parameter specifically suited for cellular imaging. We further improve the imaging capabilities of our system with a microfluidic device enabling Exchange-PAINT for multi-target imaging without chromatic offsets, using engineered point spread functions for 3D imaging, and employing deep learning algorithms for high-density localization of single molecules. Our approach achieves improved localization precision, imaging speeds, and multi-target accuracy, enabling fast and precise multi-target 3D single-molecule super-resolution cellular imaging. Here, we focus on the design and construction of our single-objective dithered light sheet and its range of applications from nuclear protein investigation to whole cell imaging. We think the improved cellular imaging resulting from this system will impact our understanding of the relationship between organization and function of subcellular structures and help us and others answer relevant biomedical questions involved in disease pathogenesis.

Fast characterization of in-plane fiber orientation at the surface of paper sheets through image analysis

The in-plane fiber orientation distribution has a decisive impact on paper mechanical and dimensional properties (e.g., tensile stiffness, hygroexpansion). It is usually estimated offline through relatively expensive bench instrumentation such as diffusion-based optical methods and ultrasonic devices. In this work we present an alternative methodology that is fast, portable, inexpensive and able to provide the complete surface polar fiber orientation profile. The proposed technology combines an image acquisition setup, consisting of a digital camera with a low angle illumination system, with the gradient-segmentation method (GSM), a robust image analysis algorithm. This camera-GSM methodology presented high internal consistency, accurately identifying the angles of samples subjected to known rotations at the imaging step. The methodology also produced comparable results to the TSO (tensile stiffness orientation) technique, used as reference. The methodology is easily transferable to plant operation, including for the online assessment of fiber orientation.

All fiber-based illumination system for multi-exposure speckle imaging.

Monitoring blood flow is critical to treatment efficacy in many surgical settings. Laser speckle contrast imaging (LSCI) is a simple, real-time, label-free optical technique for monitoring blood flow that has emerged as a promising technique but lacks the ability to make repeatable quantitative measurements. Multi-exposure speckle imaging (MESI) is an extension of LSCI that requires increased complexity of instrumentation, which has limited its adoption. In this paper, we design and fabricate a compact, fiber-coupled MESI illumination system (FCMESI) that is substantially smaller and less complex than previous systems. Using microfluidics flow phantoms, we demonstrate that the FCMESI system measures flow with an accuracy and repeatability equivalent to traditional free space MESI illumination systems. With an in vivo stroke model, we also demonstrate the ability of FCMESI to monitor cerebral blood flow changes.

Modelling of the effects of luminaire installation geometries and other factors on road illumination system photometric parameters and energy efficiency

PurposeProperly planned road illumination systems are collectively a public wealth and the commissioning of such systems may require extensive planning, simulation and testing. The purpose of this simulative work is to offer a simple approach to facilitate luminance-based road lighting calculations that can be easier to comprehend and apply to practical designing problems when compared to complex multi-objective algorithms and other convoluted simulative techniques.Design/methodology/approachRoad illumination systems were photometrically simulated with a created model in a validated software platform for specified system design configurations involving high-pressure sodium (HPS) and light-emitting diode (LED) luminaires. Multiple regression analyses were conducted with the simulatively obtained data set to propound a linear model of estimating average luminance, overall uniformity of luminance and energy efficiency of lighting installations, and the simulatively obtained data set was used to explore luminaire power–road surface average luminance characteristics for common geometric design configurations involving HPS and LED luminaires, and four categories of road surfaces.FindingsThe six linear equations of the propounded linear model were found to be well-fitted with their corresponding observation sets. Moreover, it was found that the luminaire power–road surface average luminance characteristics were well-fitted with linear trendlines and the increment in road surface average luminance level per watt increment of luminaire power was marginally higher for LEDs.Originality/valueThis neoteric approach of estimating road surface luminance parameters and energy efficiency of lighting installations, and the compendia of luminaire power–road surface average luminance characteristics offer new insights that can prove to be very useful for practical purposes.

Programmable freeform optics with extended white light sources: possibilities and limitations.

Freeform optics can be used in lighting applications to generate accurate prescribed illumination patterns from compact light sources such as LEDs. When targeting dynamic illumination systems, a time-variable optical functionality is needed. Phase-only spatial light modulators (SLMs) have been used in the past for various dynamic beam shaping applications with monochromatic, zero-étendue illumination under paraxial conditions. Such limitations can no longer hold when considering lighting applications. In this paper, a novel algorithm for the calculation of smooth phase shift patterns is presented in order to generate arbitrary target patterns from arbitrary incident wave fronts for non-paraxial conditions. When applying such phase shift patterns to SLMs, these devices can be considered as programmable freeform optics. The experimental performance of the calculated phase patterns is analyzed on a real SLM, with a maximal phase shift of 6π, for collimated laser beams and white LEDs. The possibilities and limitations of generating accurate prescribed target patterns are critically discussed in terms of the angular extent of the target pattern, the consider spectrum of the light source and the étendue of the incident light beam.

STUDY ON POCKET PROJECTORS: THE FUTURE OF PORTABLE PROJECTION TECHNOLOGY

The design characteristics of the DLP pocket projector divide it into two parts. The illumination system is one of them. It has LEDs in red, green, and blue. In order to illuminate the dichroic filter collimated, each of them has a collimator. It combines three wavelengths of light through dichroic filters. The micro-lens array, condenser, and TIR prism are the final components that are used to uniformly illuminate DMD and reduce the size of the illumination system. The imaging system is the other. In accordance with the DMD standard; the point of view, successful central length, the relationship of imaging and item and imaging nature of the focal point can be characterised. The lens was well-designed and conformed to the standards thanks to the use of optical simulation software like Code V and ZEMAX. In the end, the production tolerance was looked at. In this plan, the typical light productivity of three frequencies Drove on DMD is 51.13%, and the typical consistency on DMD is 95.17%. The average uniformity and light efficiency of the screen are 87.3% and 44%, respectively.

Complex illumination system for fast interferometric measurements

Freeform metrology is an enabling technology for today’s research and advanced manufacturing. The Tilted Wave Interferometer is a full field measurement system for fast and flexible measurements. It is based on an off-axis illumination scheme based on a microlens array. In this contribution, we present a novel illumination system for the tilted wave interferometer, that allows to reduce the measurement time by a factor of four using parallelization based on wavelength multiplexing. Here we present a design solution that utilizes the flexibility of 3D-printing. The microlenses are realized as multi-order diffractive optical elements, providing a high efficiency compared to colorfilter based realizations. To boost the light efficiency of the novel illumination system further, a field lens functionality is added to the system by adding individual micro-prisms to each microlens. The system is manufactured by the use of grayscale two-photon polymerisation.

Increasing Consumer Drone Safety Through an IoT-Based Custom Illumination System

Consumer-based drone applications have been increasing rapidly in recent years. Most of these applications, such as aerial surveillance, crop dusting, and real estate photography rely, on frameworks that are based on the Internet of Things (IoT). Although solutions have been proposed to security issues due to connectivity, physical safety issues have not been sufficiently discussed. To solve one such issue, the conspicuousness of drones during flight, we have proposed an illumination system that can adapt to different weather conditions using an IoT framework. To test the feasibility of our illumination system, we conducted two tests, a power consumption test, and a human-in-the-loop assessment. The power test showed different illumination configurations did affect power consumption. The human-in-the-loop assessment demonstrated the effect of illumination on distance perception and how sunlight levels affected the drone's preferred illumination color. As drones begin to operate in more crowded spaces, such as cities, the need to ensure the safety of the public will be paramount. Through this prototype, we aim to provide designers with guidance on how to consider illumination for safer drone operations. Future studies, we plan to explore using illumination to increase safety and congruence in future application areas, such as delivery.

ОРНАМЕНТ В СИСТЕМЕ ИЛЛЮМИНИРОВАНИЯ АРМЯНСКИХ РУКОПИСНЫХ ЕВАНГЕЛИЙ

The paper considers the functional and artistic features, the role of ornament in the system of illumination of the Armenian manuscript Gospels. In view of the fact that the Four Gospels were also used as Lectionaries and Aprakos Gospels, the Armenian scribes and miniaturists introduced new design elements into the manuscripts, different from the Byzantine tradition, which visually marked the beginning of the readings. Ornaments were used primarily for this purpose, performing the extremely important functions of subdividing the text. The ornament is present in each of the six structural components of the illumination system, shaping them: in the chorans (in the Epistle of Eusebius and the canons/tables of concordance); in title pages (in headpieces, initials and right marginalia, in letters of the text); in the portraits of the evangelists; under the headings of readings-pericopes; in decorative and narrative marginalia next to rubrics; in full-page and text miniatures. Thus, the ornament became the “lymph” of the artistic organism of the Armenian manuscript book, defining its unity and integrity.

Simulation and error analysis of illumination system with coherent noise suppression

提出通过离轴照明系统抑制相干噪声的方案,设计了一种具有抑制相干噪声能力的照明系统。通过Zemax的非序列模式对照明系统进行仿真，得到了厚度为90 μm的离轴环形光斑，验证了此照明系统对相干噪声的抑制能力。将其作为19.05 mm（3/4英寸）Fizeau干涉仪的光源，设置对比实验，光源波长为632 nm，设置圆形噪点尺寸为120 μm~500 μm和尺寸为100 μm×350 μm的划痕。对设计的照明系统进行误差分析，优化照明系统成像质量，调整干涉系统参数，最终在照明光环宽度为42 μm、干涉腔长为15 mm情况下，干涉条纹的对比度提升至97.60%。

Design and Simulation of Illumination Uniformity Unit in Lithography Illumination Systems

Design and Simulation of Illumination Uniformity Unit in Lithography Illumination Systems

Analysis of Influence of Source Parameters on Performance of Collimating Illumination System

Analysis of Influence of Source Parameters on Performance of Collimating Illumination System

Improvement of near-infrared illumination system for water vapor imaging

Improvement of near-infrared illumination system for water vapor imaging

Lithography Illumination System Based on Fourier Synthesis Technology

Lithography Illumination System Based on Fourier Synthesis Technology

Adaptive illumination systems with programmable freeform optics?

Adaptive illumination systems are capable of changing their emission pattern in a dynamic and flexible manner. Such systems can be realized with tunable optical components. We analyse the possibilities and limitations of phase-only spatial light modulators, implemented as a kind of programmable freeform optics, to realize adaptive illumination systems. First, the calculation of the required phase shift patterns to generate specific target irradiance distributions from arbitrary incident wavefronts, is elaborated. Second, the practical limitations of generating prescribed target patterns are experimentally tested and critically discussed.

Smart lighting system with tunable radiation pattern

Smart lighting systems are capable of producing light when and where it is needed. Such functionality can be achieved with adaptive optical systems, which consist of one or multiple adjustable components, enabling illumination with a variable radiation pattern. This paper introduces the design of a compact, tunable optical system, allowing illumination with variable beam size and beam direction. We demonstrate how this system can be combined with computer vision and a feedback loop, to achieve a fully autonomous, smart illumination system.

Gamma Ray Effects on Multi-Colored Commercial Light-Emitting Diodes at MGy Level

Light-emitting diodes (LEDs) are of interest for implementation in radiation environments, such as part of illumination systems of radiation-tolerant cameras able to provide images at high doses (>MGy). It is then mandatory to characterize the radiation effects on all of the LED key properties exploited for such applications. To this aim, the evolution of the optical properties of commercial LEDs after they have been exposed to γ-rays, up to total ionizing dose (TID) levels of 2 MGy(air) at room temperature, is discussed. The devices under test include four LEDs of different colors (red, green, blue and white) in the same package. This allows a direct comparison between the responses of the different structures and technologies, as the proximity between the diodes ensures the uniformity of their irradiation conditions. The radiation effect on the electron–photon conversion mechanisms inside these LEDs is investigated through the evolution of their external quantum efficiency (EQE) vs. current characteristics. The spectral emission pattern of LEDs after irradiation at different dose levels is then characterized to estimate the TID effects on the lens which surrounds the LED package. The presented results show a monotone radiation-induced EQE decrease as a function of the TID, especially in the red LEDs. For the tested red LEDs, the EQE decreased up to 78% after a TID of 1 MGy when they were OFF during irradiation, and up to 8% when they were ON during irradiation. A visual inspection of the devices after irradiation shows a mechanical degradation of the lens shared among the four diodes. However, the emission pattern analysis does not show any significant radiation-induced changes in the optical properties of the lens. Based on these results, it appears possible to design LED-based illumination systems able to survive to MGy dose levels that can be integrated as subsystems of radiation-hardened cameras.

Illumination system optimal design for geometry measurement of complex cutting tools in machine vision

Precision geometry measurement of complex cutting tools has a significant impact on the machinability of components in the industry. However, acquiring high-quality images in machine vision is a challenging problem due to the large slope and complex geometry. In view of the vital function of illumination, this paper proposed a method of optimal design for the LED array. First, the calculation model of irradiance distribution on the measurement plane is established, and the properties of the reflected light from the surface of cutting tools are analyzed based on the BRDF theory. Then, the optimal parameters are solved through the specific algorithm flow for the LED array design. Finally, a flexible LED light source is fabricated with the optimal parameters for different features of the cutting tools and used in the measurement. The measurement results show that the error of the optimized light source is less than 1%, and compared with the off-the-shelf light, the measurement accuracy is improved by 9.5% on average. Moreover, this method also presents the potential applied to other complex objects.