Il prodotto illustra la partecipazione di ITC-CNR al Workshop IEA-SHC Task 70 "Low-carbon and high-comfort integrated lighting" Lund, Svezia 4-5 Ottobre 2022 svolto in modalità ibrida. Come da agenda del workshop, ITC-CNR ha presentato le proprie esperienze di ricerca in campo illuminotecnico e del benessere visivo, nonchè le infrastrutture di ricerca dedicate e/o potenzialmente utilizzabili nell'ambito delle attività previste nel Task 70.

Fourier ptychographic microscopy probes label-free samples from multiple angles and achieves super resolution phase-contrast imaging according to a synthetic aperture principle. Thus, it is particularly suitable for high-resolution imaging of tissue slides over a wide field of view. Recently, in order to make the optical setup robust against misalignments-induced artefacts, numerical multi-look has been added to the conventional phase retrieval process, thus allowing the elimination of related phase errors but at the cost of a long computational time. Here we train a generative adversarial network to emulate the process of complex amplitude estimation. Once trained, the network can accurately reconstruct in real-time Fourier ptychographic images acquired using a severely misaligned setup. We benchmarked the network by reconstructing images of animal neural tissue slides. Above all, we show that important morphometric information, relevant for diagnosis on neural tissues, are retrieved using the network output. These are in very good agreement with the parameters calculated from the ground-truth, thus speeding up significantly the quantitative phase-contrast analysis of tissue samples.

Fourier Ptychography probes the sample from different directions to achieve label-free quantitative phase imaging with a large space-bandwidth product. However, special attention has to be paid in the calibration of the optical setup to assure the accurate knowledge of the geometrical parameters involved in the image reconstruction. Any slight misalignment can provoke incorrect synthesis of the observables and, in turn, severe phase errors in the resulting high-resolution image. Here, we present a new processing pipeline that automatically removes such a priori unknown artifacts, thus making Fourier Ptychography miscalibration-tolerant. This result is achieved through a numerical Multi-Look approach that generates and combines multiple reconstructions of the same set of observables where phase artifacts are largely uncorrelated and, thus, automatically suppress each other. The proposed method is non-iterative, fully parallelizable, and completely blind, unlocking the use of Fourier Ptychography as an easy to handle tool or add-on to existing microscopes to be employed by unskilled users, thus paving the way to biomedical and clinical practices.

Many literature studies demonstrated that technologies belonging to cognitive neuroscience can be used in museums. Physics, optics, thermodynamics and neurosciences applications can provide an important support to applied and practical research for lighting our Cultural Heritage. In our research we provided a multidisciplinary integrated approach for the study of the luminous climate inside a historical building: Villa La Quiete in Florence is the case study. The quantitative measurements of the relationship between observer and artworks were performed, with eye-tracking technique application. The Information Theory, read on a thermodynamic basis, the ergonomy of the multi-perceptive learning and optical physics, were the fundamental tools for the assessment of the correct light sources in terms of spectral emission and colour light temperature. The eye-tracking technique combined with the results of lighting parameter quantification, allowed checking how the colour of light changes the observer's perception, and from the information theory point of view, the communication and interpretation process of the signals due to different lighting. At the same time, it was also possible to measure by assessing the perceptive data of the visual path, and thus the neg-entropy, the informative content of the interaction of light with works of art.

Camera triggering represents an essential step for synchronizing artificial vision systems (AVSs) and can affect the quality of acquired images. In fact, a proper trigger signal is mandatory to synchronize in time both stand alone or multiple cameras covering large environments. In addition, indoor environments with artificial light sources can induce flickering noise in captured frames, affecting the performance of the algorithms that are usually executed to interpret a scene or perform various tasks. In this letter, we describe the design of an embedded system for camera triggering that can be employed to deal with such issues and remove flickering noise while capturing an image with the highest possible dynamic range. Experiments on real data show how the proposed trigger can be effectively employed in AVSs.

The European Union set the ambitious target of reducing the final energy consumption by 20% within 2020. This goal demands a remarkable change in how we generate and consume energy and urgently calls for an aggressive policy on energy efficiency. Since almost 20% of the European electrical energy is used for lighting, considerable savings can be achieved with the development of novel and more efficient lighting concepts [1]. In the last decades, several outstanding goals have been achieved in this area, for instance with the invention of blue Light-Emitting Diodes (LED), which was awarded the Nobel Prize in Physics in 2014, and the commercialization of the first displays based on Organic Light-Emitting Diodes (OLEDs), allowing the fabrication of flexible and ultrathin luminescent surfaces. Within this framework, our research group has been involved in the development of a new concept for flat and flexible electroluminescent devices, i.e. the Light-Emitting Electrochemical Cells (LECs) [2a]. Such devices rely on a much simpler architecture compared to OLEDs and they are therefore expected to be a viable low-cost alternative to the technologies already on the market [2]. In this talk, some of the objectives we accomplished in the development and characterization of emitting materials for LECs will be presented. The first part of the presentation will be focused on cationic cyclometalated iridium(III) complexes, with a particular emphasis on deep-blue emitting materials since they turned out to be rather challenging due to emission red-shift in the solid state and instability under operative conditions [3]. In the second part, cationic copper(I) complexes as a potential alternative to iridium(III) counterparts will be discussed [4]. Iridium, in fact, is one of the rarest elements on the Earth crust and, therefore basing a largescale lighting industry on this metal might be unrealistic. Copper, on the other hand, is much more abundant and cheaper, but exhibits several drawbacks if used as metal center for luminescent complexes, such as limited color tunability and low stability in the devices. 1. (a) L. S. Brown, Plan B. Mobilizing to save the civilization, W. W. Norton & Company, New York, 2009. (b) Light's Labour's Lost - Policies for Energy-efficient Lighting, tech. rep., International Energy Agency, 2006. 2. (a) https://www.cello-project.eu/ (b) R. D. Costa et al., Angew. Chem., Int. Ed., 2012, 51, 8178. 3. (a) N. M. Shavaleev et al., Inorg. Chem., 2012, 51, 2263; (b) F. Monti et al., Inorg. Chem., 2013, 52, 10292; (c) F. Monti et al., Inorg. Chem., 2014, 53, 7709; (d) F. Monti et al., Inorg. Chem., 2015, 54, 3031; (e) F. Monti et al., Faraday Discuss., 2015, 185, 233. 4. (a) A. Kaeser et al., Inorg. Chem., 2013, 52, 12140; (b) M. Mohankumar et al., Chem. Eur. J., 2014, 20, 12083; (c) J.-J. Cid et al., Polyhedron, 2014, 82, 158.

Outdoor lighting and traffic signaling are emerging fields of application for the Light Emitting Diode technology. These sustainable power-saving illumination sources can be used thanks to the availability of high-power white LEDs that, combined with suitable lenses, permit to obtain various angular distributions of the light for many applications. The proposed LED lamp for street lighting produces high illuminance uniformity utilizing only reflective components, avoiding free-form optics: the luminous flux generated by the LEDs illuminates the roadway both directly and reflecting on the inner surface of reflectors with double curvature. It allows preventing the employment of plastic lenses, subjected to risks of yellowing and decrease of transparency. The results in terms of simulated illuminance on the road show high values of uniformity. Moreover, the optical modelling was aimed to design a configuration actually feasible from a technical point of view.

Luminescence and photoinduced energy and electron transfer are fundamental processes that are acquiring an increasing importance for a number of applications in several fields. Our group is particularly concerned with those related to lighting and solar energy conversion, which entail the design, preparation and characterization of suitably designed molecules, metal complexes, supramolecular arrays and nanomaterials. Some of our recent results in this area will be briefly illustrated, particularly on (i) transition metal complexes, (ii) luminescent hybrid materials made of inorganic luminophores and carbon nanotubes, and (iii) photoinduced processes in multichromophoric systems containing fullerene as electron acceptor combined with suitable electron donors. In an effort to keep a tutorial approach and a broader view, we will introduce the data presented in light of their potential applications and, more generally, in the context of the energy transition to be accomplished in the present century.

A promising application of the emerging LED technology is traffic signalling, exploiting the norms evolution. The concept is practically illustrated in case of an authentic source for maritime signalling. The new sustainable lamp recombines multiple separated LEDs, realizing a quasi-punctual localized source. The lamp optical design is based on the practical features of the real device and on the relevant norms requirements. After the installation, specific photometric tests verified that the new LED-based source satisfied the illumination requirements. The obtained LED signalling device is more durable and reliable. In future the application of these sustainable sources could be extended to other traffic signalling systems. The aim is to substitute the typical high-consuming short-life lamps with power-saving long-life LED-based sources. © 2014 AEIT.

In the context of real-time, GPU-based rendering of animated skinned meshes, we propose a new algorithm to compute surface normals with minimal overhead both in terms of the memory footprint and the required per-vertex operations. By accounting for the variation of the skinning weights over the surface, we achieve a higher visual quality compared to the standard approximation ubiquitously used in video-game engines and other real-time applications. Our method supports Linear Blend Skinning and Dual Quaternion Skinning. We demonstrate the advantages of our technique on a variety of datasets and provide a complete open-source implementation, including GLSL shaders.

This paper presents the development and optimization of an ultrasensitive light dosimeter, especially designed for the preventive risk assessment of damage to highly photosensitive artefacts. This indicator, named LightCheck® Ultra, is composed of a photosensitive dye/polymer layer applied on a paper support. The indicator is characterized by a progressive colour variation as the exposure to light increases. Initially blue, the colour successively changes through purple and pink to white, under the effect of visible light. The colour variation was investigated under different environmental conditions. The light-induced alterations under study were evaluated using various light sources and illuminance levels. The impact of otherfactors unconnected to light (such as temperature, humidity, indoor air pollution - atmospheric and volatile organics - and oxygen) was also studied. The behaviour of the indicator in the field in selected museums and historic houses was assessed in parallel with the laboratory experiments at each development stage. Finally, the calibration was carried out and a reference colour scale was provided for fast and easy reading of the indicator. By means of this reference colour scale, the colour exhibited by the dosimeter after an exposure can be easily correlated to a quantitative indication of the light dose received. The phases of development and testing of this novel light dosimeter are presented in detail, from the early design to the final product.