恒照度调光的LED驱动器设计

随着照明技术的不断发展以及能源的日益紧张,绿色照明成为主要的研究方向。本文针对传统照明能效低、耗电量大等问题,设计了LED恒照度调光驱动器。系统使用恒流LED控制芯片NCL30160作为LED光源驱动电路,采用TSL2561光照度传感器采集室内光照度,通过处理器相应算法进行闭环控制,实现室内的恒照度调光。该算法实现了PWM波形平滑变化,避免因PWM突变造成闪光。同时,系统增加了人体运动控制,实现无人、有人时的不同调光方案,使设计进一步节能和智能化。     

A Quick Rendering Method Using Basis Functions for Interactive Lighting Design

When designing interior lighting effects, it is desirable to compare a variety of lighting designs involving different lighting devices and directions of light. It is, however, time-consuming to generate images with many different lighting parameters, taking interreflection into account, because all luminances must be calculated and recalculated. This makes it difficult to design lighting effects interactively. To address this problem, this paper proposes a method of quickly generating images of a given scene illustrating an interreflective environment illuminated by sources with arbitrary luminous intensity distributions. In the proposed method, the luminous intensity ditribution is expressed with basis functions. The proposed method uses a series of spherical harmonic functions as basis functions, and calculates in advance each intensity on surfaces lit by the light sources whose luminous intensity distribution are the same as the spherical harmonic functions. The proposed method makes it possible to generate images so quickly that we can change the luminous intensity distribution interactively. Combining the proposed method with an interactive walk-through that employs intensity mapping, an interactive system for lighting design is implemented. The usefulness of the proposed method is demonstrated by its application to interactive lighting design, where many images are generated by altering lighting devices and/or direction of light.     

Lighting Layout Optimization for 3D Indoor Scenes

As the number of models for 3D indoor scenes are increasing rapidly, methods for generating the lighting layout have also become increasingly important. This paper presents a novel method that creates optimal placements and intensities of a set of lights in indoor scenes. Our method is characterized by designing the objective functions for the optimization based on the lighting guidelines used in the interior design field. Specifically, to apply major elements of the lighting guideline, we identify three criteria, namely the structure, function, and aesthetics, that are suitable for the virtual space and quantify them through a set of objective terms: pairwise relation, hierarchy, circulation, illuminance, and collision. Given an indoor scene with properly arranged furniture as input, our method combines the procedural and optimization‐based approaches to generate lighting layouts appropriate to the geometric and functional characteristics of the input scene. The effectiveness of our method is demonstrated with an ablation study of cost terms for the optimization and a user study for perceptual evaluation.     

在一张室内照片上模拟太阳不同照射效果的方法

提出一种在一张室内场景照片基础上，绘制新的光照效果的方法，主要内容包括：给出模拟不同时间太阳光照效果的基本方法；为简化阴影的计算，推导出一种在新的光照条件下计算阴影的简单算法；给出一种模糊阴影边界的生成方法。文中方法适合于动画制作、虚拟房产观察，室内灯光设计等。     

Neuro-controller for broadcast lighting light-emitting diode to express white light with high color rendering index

Technical characteristics analysis related to correlated color temperature (CCT), color rendering, and illuminance is required to use light-emitting diode (LED) as broadcast lighting. In general, to realize a white light source with a high color rendering index (CRI), we selected the appropriate emission intensity of RGBW LED through trial and error. However, the characteristics of the LED light source and environmental conditions make it difficult to perform the procedure several times. The objective of this study was to design a system that could control illuminance, CCT, and ∆uv while having high CRI, as an LED control method for broadcasting lighting. The controller implements using a feed-forward neural network with excellent nonlinear function approximation capability. We measure data directly from the red green blue white (RGBW) LED system for neural network training. We then select data with high CRI from the measured raw data and choose data for neural network learning by removing measurement noise using the quadratic polynomial interpolation method. The performance evaluation confirms that the proposed neural network controller shows excellent results as an RGBW LED controller for broadcast lighting in the Planckian locus and all regions of white light.     

室内照度积分计算方法的改进

利用照度积分计算方法求空间任意点的照度，结果误差较大。本文考虑光线反射、灯管老化及灯罩反射损耗等因素的影响，排除自然光因素，提出了一种改进的照度积分计算方法。实测数据计算结果比对证实，新的计算方法提高了计算精度。     

Interactive Lighting Design with Hierarchical Light Representation

Lighting design plays a crucial role in indoor lighting design, computer cinematograph and many other applications. Computer‐assisted lighting design aims to find a lighting configuration that best approximates the illumination effect specified by designers. In this paper, we present an automatic approach for lighting design, in which discrete and continuous optimization of the lighting configuration, including the number, intensity, and position of lights, are achieved. Our lighting design algorithm consists of two major steps. The first step estimates an initial lighting configuration by light sampling and clustering. The initial light clusters are then recursively merged to form a light hierarchy. The second step optimizes the lighting configuration by alternatively selecting a light cut on the light hierarchy to determine the number of representative lights and optimizing the lighting parameters using the simplex method. To speed up the optimization computation, only illumination at scene vertices that are important to rendering are sampled and taken into account in the optimization. Using the proposed approach, we develop a lighting design system that can compute appropriate lighting configurations to generate the illumination effects iteratively painted and modified by a designer interactively.     

点光源环境下室内环境灯光多参量控制仿真

为提高室内环境灯光照射的自适应性能,需联合控制灯光参量.提出基于模糊PID的点光源环境下室内环境灯光多参量的控制方法.基于动态基元的自适应学习方法,构建室内环境灯光控制的约束参量模型,在模型参数约束下采用多自由度耦合调节方式,调节室内环境灯光的亮度和角度;采用模糊PID控制方法,进行灯光的亮度信息和光源输出信息的融合处...     

Inverse lighting design for interior buildings integrating natural and artificial sources

In this paper we propose a new method for solving inverse lighting design problems that can include diverse sources such as diffuse roof skylights or artificial light sources. Given a user specification of illumination requirements, our approach provides optimal light source positions as well as optimal shapes for skylight installations in interior architectural models. The well known huge computational effort that involves searching for an optimal solution is tackled by combining two concepts: exploiting the scene coherence to compute global illumination and using a metaheuristic technique for optimization.Results and analysis show that our method provides both fast and accurate results, making it suitable for lighting design in indoor environments while supporting interactive visualization of global illumination.     

Objective and subjective assessments of lighting in a hospital setting: implications for health,safety and performance

A field study was conducted to evaluate the illumination levels, to examine the effect of lighting conditions (including lighting characteristics and disturbances) on employee satisfaction, job performance, safety and health, and to compare the employees' perception of lighting level with actual illuminance levels in a hospital setting using both questionnaire and physical illuminance measurements. The illumination levels varied across different locations within the hospital and were lower than standards for 52.2% of the workplaces surveyed. Most respondents indicated that at least one of the four lighting characteristics (i.e. light level, type of light sources, light colour and use of daylight) was inappropriate, and that at least one of the three lighting disturbances (i.e. flickering lights, glare and unwanted shadows) was a major disturbance to them. The employees' perceptions of illuminance generally reflected the actual illuminance levels. The more appropriate maintenance or installation of lighting fixtures was rated as the most appropriate for improving lighting. The findings suggest that environmental ergonomics should be given a more prominent role in hospital building and workplace design to support safer healthcare facilities (for staff and potentially for patients).

Practitioner Summary: Good lighting is essential to improve employee performance, health and safety. The findings suggest that quantitative physical measurements should be supplemented by qualitative subjective assessments to provide a more holistic approach where specific details about the lighting condition in each working environment are incorporated from the workers' perspective.     

基于改进粒子群算法的分布式智能照明系统

针对现有公共建筑照明系统存在的高成本、分布式与集中式控制结合能力不高、交互性不强等问题,应用智能优化算法,在分布式框架上实现区域协同照明控制。通过采集窗户处照度信息,预测透过窗户的自然光在工作面上产生的照度值,当自然光不足需要人工光源补充时,通过协同配合,各区域利用改进粒子群算法计算出区域内最佳的灯具开度组合,达到均匀照明,实现舒适性与节能的最佳综合。当照明需求改变时,可以通过WEB端进行修改。最后,通过实际办公室模型在DIALux evo上进行仿真验证。在不同照明需求和环境条件下,实验结果表明相较于普通控制方式（全开全关）,该方法在节能和舒适度上具有良好的性能,能有效控制工作面照度,各工作面的最大照度误差都在10%之内,控制方案切实可行,具有实用价值。     

基于自适应领域算法的智能照明控制系统

提出一种新型的智能照明控制系统,该系统基于一种新型自适应算法ANA／CC（基于相关性系数的自适应领域算法）,运用最新提出的可视光通信技术在照明设备和照度传感器之间建立直接的通信,从而为特定的地点提供所需要的照度,在整个系统建立的过程中,为该系统建立控制模型。经过实验和仿真发现,该模型可以在短时间内将测试地点的照度达到目标值。     

机器视觉系统中的照明优化设计

在设计机器视觉系统的照明部分时,需要根据应用环境和设备成本来选择光源,涉及到光源的照射方式、色谱范围、照明类型、光波极性、光强等问题。为了使被拍摄物能够在相机传感器上清晰成像,需要分析从被拍摄物反射到相机传感器上的光能及所需光源能量。结合CCD特性,提出了一种照明优化设计方法,导出了CCD传感器的成像值和光照能量之间的关系,对机器视觉系统中合理选择光源和优化照明设计具有指导作用,在检测技术与自动化装置研究领域具有重要的实用意义。     

Low cost multimedia sensor networks for obtaining lighting maps

In many applications, video streams, images, audio streams and scalar data are commonly used. In these fields, one of the most important magnitudes to be collected and controlled is the light intensity in different spots. So, it is extremely important to be able to deploy a network of light sensors which are usually integrated in a more general Wireless Multimedia Sensor Network (WMSN). Light control systems have increasing applications in many places like streets, roads, buildings, theaters, etc. In these situations having a dense grid of sensing spots significantly enhances measuring precision and control performance. When a great number of measuring spots are required, the cost of the sensor becomes a very important concern. In this paper the use of very low cost light sensors is proposed and it is shown how to overcome its limited performance by directionally correcting its results. A correction factor is derived for several lighting conditions. The proposed method is firstly applied to measure light in a single spot. Additionally a prototype of a sensor network is employed to draw the lighting map of a surface. Finally the sensor grid is employed to estimate the position and power of a set of light sources in a certain region of interest (street, building, …). These three applications have shown that using low cost sensors instead of luxmeters is a feasible approach to estimate illuminance levels in a room and to derive light sources maps. The obtained error measuring spots illuminance or estimating lamp emittances are quite acceptable in many practical applications.     

The impact of light and colour on psychological mood: a cross-cultural study of indoor work environments

The aim of the study was to determine whether indoor lighting and colour would have any systematic impact on the mood of people working indoors. Earlier studies have mostly focused either on light, colour or windows in laboratory settings. The present study was carried out in real work environments at different seasons and in countries with different latitudes. A total of 988 persons completed all parts of the study. In the countries situated far north of the equator there was a significant variation in psychological mood over the year that did not occur in the countries closer to the equator. When all four countries were considered together, it became evident that the light and colour of the workplace itself also had an influence on the mood of persons working there. The workers' mood was at its lowest when the lighting was experienced as much too dark. The mood then improved and reached its highest level when the lighting was experienced as just right, but when it became too bright the mood declined again. On the other hand, the illuminance as measured in objective terms, showed no significant impact on mood at any time of the year. The relationship between mood and the distance to the nearest window was bimodal. The results also indicate that the use of good colour design might contribute to a more positive mood. It is suggested that in future research light and colour should be studied as parts of the more complex system making up a healthy building.     

The impact of light and colour on psychological mood: a cross-cultural study of indoor work environments

The aim of the study was to determine whether indoor lighting and colour would have any systematic impact on the mood of people working indoors. Earlier studies have mostly focused either on light, colour or windows in laboratory settings. The present study was carried out in real work environments at different seasons and in countries with different latitudes. A total of 988 persons completed all parts of the study. In the countries situated far north of the equator there was a significant variation in psychological mood over the year that did not occur in the countries closer to the equator. When all four countries were considered together, it became evident that the light and colour of the workplace itself also had an influence on the mood of persons working there. The workers' mood was at its lowest when the lighting was experienced as much too dark. The mood then improved and reached its highest level when the lighting was experienced as just right, but when it became too bright the mood declined again. On the other hand, the illuminance as measured in objective terms, showed no significant impact on mood at any time of the year. The relationship between mood and the distance to the nearest window was bimodal. The results also indicate that the use of good colour design might contribute to a more positive mood. It is suggested that in future research light and colour should be studied as parts of the more complex system making up a healthy building.     

Vision ergonomics at recycling centres

All municipalities in Sweden offer their inhabitants a service for disposing of large-size and hazardous waste at local recycling centres. Opening hours at these centres include hours of darkness. The aims of this study were to 1) describe user and employee experiences of lighting and signs at Swedish recycling centres, 2) measure and assess the lighting system at the two recently built recycling centres in Linköping and to assess the legibility and visibility of the signs used and 3) propose recommendations regarding lighting and signs for recycling centres. Interviews and questionnaires were used to assess experiences of employees and users, and light measurements were performed. By observing users, activities with different visual demands at different areas within the recycling centres were identified. Based on the literature, standards and stakeholder experiences, recommendations regarding lighting systems and sign design, illuminance, luminance and uniformity are proposed for recycling centres.     

A simple method for designing efficient public lighting,based on new parameter relationships

New parameter relationships for public lighting design (i.e. average illuminance, luminaire spacing, and mounting height) were calculated from a large sample of data sets optimized with a multi-objective evolutionary algorithm. Optimization criteria included maximum energy efficiency and overall uniformity. The relations thus derived are a simple and elegant method for designing any type of public lighting installation without the need to use complex, expensive and/or unavailable software. It would therefore be desirable that manufacturers include such parameters in the product datasheet in order to make the calculation easier.     

基于ZigBee的室内智能照明系统设计

为了改进传统室内照明系统存在的布线复杂、节能效果差、不易智能控制等缺点,分析了基于ZigBee技术的室内照明系统的设计和实现方法。该系统的硬件设计基于支持ZigBee的SoC芯片CC2530,软件设计则采用TI公司的Z-Stack协议。系统可以通过PC机上的上位机界面实现对灯节点的单控、组控、全控以及调光控制,并具有耗电小,成本低、无需布线和安装方便简单等特点。     

Multi-objective optimization of the light guide rod by using the combined Taguchi method and Grey relational approach

The light guide rod (LGR) is widely used to transmit light from a light emitting diode lamp. In this paper, a designed LGR for the application in the automobile lighting is prepared. The main factors that affect the LGR performances are the illuminance flux and uniformity. This paper aims to develop a method that optimizes the multi-objective parameters of the LGR. For statistical purposes, the experimental parameters for the LGRs are put in the L ₉(3⁴) orthogonal array. In order to optimize these parameters, a method combining Taguchi method and Grey relational approach is established. The experimental results from illuminance flux and uniformity can be integrated into a single performance index. A comparison of the integrated performance index between the initial and optimal conditions shows that the illuminance flux increases from 1.14 to 1.42(lm) and the average difference from 1.46 to 1.07. The positive gains for the illuminance flux and the average difference value by this approach and compared with the initial condition are reported as 25.04 and 26.64 %, respectively.