Search Results (90)

Objective: To predict pixel-wise retinal thickness maps from near-infrared (NIR) fundus images using deep learning (DL), and to identify image features in NIR fundus photographs serving as surrogate markers of retinal thickness, with implications for decentralized diabetic macular edema (DME) screening, progression monitoring, and treatment assessment. Methods: A DL model based on a U-Net architecture was trained on paired NIR fundus and OCT images from 531 eyes across three groups: healthy controls, diabetic retinopathy (DR) without DME, and DME. Model performance was evaluated using mean absolute error (MAE), root mean squared error (RMSE), structural similarity index (SSIM), and center-involved DME (ci-DME) classification at a central subfield thickness threshold of 300 µm. Controlled image manipulation experiments, including spatial disruption of vascular patterns, relocation of hard exudates, and contrast enhancement, were performed to identify image-level features serving as surrogate markers of retinal thickness. Results: The model achieved an MAE of 30.41 ± 18.68 µm, RMSE of 36.14 ± 21.05 µm, and SSIM of 0.87 ± 0.04 across the macula, with consistent performance across ETDRS subfields. For ci-DME classification, it achieved an accuracy of 84.1%, sensitivity of 69.1%, and specificity of 88.7%. Interpretability analyses were performed as qualitative assessments to visualize image regions contributing to model predictions. These analyses highlighted retinal vascular structures, hard exudates, and local contrast variations as visual features observed in relation to model outputs. Conclusions: NIR fundus images contain sufficient structural information to support pixel-wise retinal thickness estimation, with vascular architecture, hard exudates, and local contrast variations identified as image features potentially associated with model predictions. These findings suggest that NIR-based deep learning approaches may have potential applications in the assessment of diabetic macular edema and warrant further prospective and external validation to determine their role in screening, triage support, longitudinal monitoring, and treatment-related assessment, particularly in decentralized and re-source-limited care environments. Full article

This research provides new insights into the materials, methods of application and modification of the black lines used by Piet Mondrian (1872–1944) in his Neoplastic works. Interesting information was gained from letters and studio photographs, the making of mock-ups and reconstructions, and the in-depth study of four paintings, dated between 1921 and 1938, in the collection of Fondation Beyeler (Riehen/Basel, Switzerland)—Tableau I (1921–1925), Composition with yellow and blue (1932), Composition with double line and blue (1935) and Picture no. III (1938)—as well as the examination of an unfinished painting, Composition with red (1934, private collection). The four paintings were investigated with high-magnification stereomicroscopy, technical photography in transmitted light and raking light, X-rays and infrared reflectography. Detailed information about the buildup and composition of the layers was gathered with the study of cross sections and microsamples, using optical microscopy and chemical analyses. It was shown that Mondrian frequently moved the lines and changed their width up to the very last working phase and, probably, did not use a ruler in the traditional sense to achieve straight lines. In one of the works, Mondrian even employed a pencil, tracing a groove in the wet paint to accentuate straight edges. The black lines consist of multiple paint layers of diluted bone black oil paint, added with small amounts of coloured paint, alternated with thin oil-resin layers, sometimes containing lead white particles. Finally, a thin (pigmented) oil-resin finish was applied on top of the black line. Full article

The Victoria and Albert Museum in London has two ancient Egyptian painted burial shrouds in its collection. Both dating to between the 1st century BCE and early 2nd century CE, they were examined and conserved in preparation for display in the 2025 exhibition ‘Making Egypt’. A nearly intact shroud depicts a woman in the form of Hathor, whilst an incomplete shroud depicts a man as Osiris. Both shrouds would have been placed over mummified bodies, likening the deceased to deities associated with death, and therefore ensuring their place in the afterlife. Both acquired in 1900, the shrouds underwent adhesive lining treatments in the 1970s, and required further intervention in 2024 to make them suitable for display and subsequent long-term storage. Analysis was undertaken to understand their creation process, identify the pigments used, and investigate whether there is evidence of modern interventions. Methods included technical photography (under visible and ultraviolet illumination), digital microscopy, infrared reflectography (IRR), scanning X-ray fluorescence imaging (XRF) and Raman microscopy. This aimed to characterise the artists’ materials, determine the presence of modern pigments, and identify historic pesticide treatments. In preparation for display, the full shroud underwent a complete conservation re-treatment. The smaller shroud fragment underwent supplementary conservation. Both were then framed and glazed for display and future long-term storage. Full article

The 17th-century stucco altar dedicated to St. Michael the Archangel is an interesting, but very damaged, artwork located in the complex of St. Angel in the little town of Barbarano Romano in Central Italy. During the recent and quite necessary restoration carried out by University of Tuscia students on the Conservation and Restoration of Cultural Heritage Master’s program, some problems with the surface coating were encountered in the cleaning phase. Diagnostic and scientific analyses were crucial to better understanding the composition of these materials to perform the safest and most efficient cleaning procedures. The first of many steps required by this approach was an in situ analysis, starting from on-site analysis and diagnostic documentation through X-ray fluorescence spectroscopy and ultraviolet fluorescence photography, followed by laboratory investigations. The latter included µ-Raman and Fourier transform infrared spectroscopies, gas chromatography coupled with mass spectrometry, and scanning electron microscopy equipped with an energy-dispersive detector. Each technique provided useful data to determine the chemical composition of the white surface coating, which was found to be a non-original overpaint containing lead and organic binder. This overpaint had been applied to retouch the white stucco during a previous restoration project. All this new information contributed to achieving the final decision to remove this layer. Full article

This paper presents the results of the historical and artistic documentation and the conservation assessment of a tag by Muelle, a pioneering Spanish graffiti artist, in the city of Vigo (Galicia, Spain). Attribution of the tag is primarily based on evidence of the artist’s presence in the city in the late 1980s, such as by different graffiti elements in the form of tags. To increase the understanding of the technique and materials used, the tag and its substrate were documented and examined by digital photography and hyperspectral imaging. Microsamples of the tag and substrate were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, optical microscopy, and scanning electron microscopy to characterize the materials and assess the tag’s state of conservation. This work enabled us to document the tag within the context of its creation and to establish hypotheses regarding the intention behind it. We confirmed that the tag has been weathered by degradation processes that typically affect contemporary urban art, with scaling caused by deterioration of the substrate being the most important type of alteration. The results of this multidisciplinary study will be key to identifying the most appropriate intervention measures to ensure the tag’s conservation and the transmission of its legacy. Full article

The courtship behavior of moths is closely related to the biosynthesis and release of sex pheromones. To understand the mechanisms of the reproductive behavior of the ghost moth Endoclita davidi, a host insect of Cordyceps xuefeng (Ophiocordyceps xuefengensis), this study examined the courtship behavior and the ultrastructure of the sex pheromone gland of E. davidi. Infrared photography was used to analyze the courtship behavior, while SEM, paraffin tissue sectioning, and TEM were employed to examine the sex pheromone glands on the hind tibia. The courtship behavior of E. davidi occurs during the scotophase, during which males vibrate their wings and unfold the hairpencils located on the hind tibiae to lure the female moths. The hairpencil’s surface features regular longitudinal ridges interspersed with multiple circular pits. Multiple small holes were evident on the slightly enlarged areas close to the ends of the hairpencils. These small holes, formed at the base of the circular pits, connect to the internal glandular duct within the hairpencil, which links to the tibia glandular canal. The epidermal layer of the hind tibiae contains numerous glandular canals and dense microvilli. The glandular cells, specialized from dermal cells, contain numerous mitochondria, rough endoplasmic reticulum, clear vesicles of varying sizes, and round lipid droplets. The sex pheromone glands of male E. davidi release pheromones through the hairpencils in the hind tibia. The courtship behavior and ultrastructure of the sex pheromone gland of the male E. davidi provide a basis for further understanding pheromone release and communication mechanisms. Full article

Urban pollution—especially SO₂ and particulate matter—rapidly darkens and degrades outdoor-exposed wall paintings due to soiling. Laser cleaning has emerged as a cutting-edge solution, offering selective removal of contaminant layers while preserving the integrity of the underlying materials. This study explores the performance of a 355 nm Nd:YAG laser in cleaning artificially aged paint mock-ups coated with real diesel soot and exposed to an accelerated aging test with SO₂ exposure. Traditional mineral pigments—silicates (Egyptian blue, ultramarine blue, and green earth), oxides (chromium green, mars red), and a sulphide (cinnabar)—were applied following fresco and secco (egg yolk) techniques, allowing researchers to uncover how pigment chemistry and binders affect laser sensitivity. Damage thresholds were first determined for each pigment and painting technique via digital photography, stereomicroscopy, and colour spectrophotometry. Cleaning efficacy was then assessed by stereomicroscopy, colour spectrophotometry, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The results revealed clear patterns: silicate pigments exhibit stability under laser irradiation, enabling safe cleaning, whereas mars red and cinnabar remain highly sensitive regardless of the technique. Generally, secco paintings were more susceptible to laser radiation than fresco. These finding provide practical guidance for optimising laser-cleaning protocols while safeguarding the delicate surfaces of historic wall paintings. Full article

Two folding screens by futurist artist Giacomo Balla (1871–1958) in the collection of the Kröller-Müller Museum (the Netherlands) were investigated: Paravento con linea di velocità (1916–1917) and Paravento (1916/1917–1958). The screens are painted on both sides, the first on four canvases, stretched onto two wooden strainers and framed with painted wooden strips, and the second on wooden panels set into four painted stiles. In the past, damages on Paravento con linea di velocità were restored by conservators, while Paravento was probably first reworked by the artist himself and later restored by conservators. Yellowed varnish and discolored retouches on both screens led to a wish for treatment. The aim of this research was to gain insight into the painting techniques, layer buildup, pigments, binders, and varnishes of the two artworks. This information supported the decision making for treatment, and it broadens the knowledge on the materials used by Balla. Up to now, only a few published studies deal with the technical examination of paintings by this artist. Both folding screens were subjected to technical photography (UV, IR photography, and X-ray) and were examined with portable point X-ray fluorescence (pXRF) and Raman spectroscopy. Moreover, samples were taken. Cross-sections were studied with optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), attenuated total reflection Fourier-transform infrared (ATR-FTIR) imaging, and micro-Raman spectroscopy. Loose samples were examined with SEM-EDX, FTIR and micro-Raman spectroscopy, and pyrolysis gas chromatography mass spectrometry (Py-GC/MS). For Paravento con linea di velocità, all pigments and fillers of the painted canvases are compatible with the dating of the screen (1916–1917), but they differ from those on the frame. Here, rutile, in combination with various pigments, among which are blue copper phthalocyanine (PB15) and other synthetic organic pigments, was found. This indicates that the frame has been painted later, likely after the Second World War. The composition of the binders differs as well. Drying oil and pine resin have been used on the canvases, explaining the smooth and glossy appearance and solvent-sensitivity of the paint. On the frame, oil with some alkyd resin was identified. The provenance of the screen before 1972 is not clear, nor when the frame was made and painted and by whom. The results for Paravento indicate that the palettes of the two sides—painted in different styles—are comparable. Mainly inorganic pigments were found, except for the dark red areas, where toluidine red (PR3) is present. pXRF showed high amounts of zinc; cross-sections revealed that zinc white is present in the lower layers. These pigments are compatible with the dating of the screen (1916–1917). In many of the upper paint layers though, except for some green, dark red, and black areas, rutile has been identified. This indicates that these layers were applied later, likely after the Second World War. Since this folding screen was used by the artist and his family until his death in 1958, it seems likely that Balla himself reworked the screen. Full article

This paper provides an overview of artificial intelligence (AI) applications in ophthalmology, with a focus on diagnosing dry eye disease (DED). We aim to synthesize studies that explicitly compare AI-based diagnostic models with clinical tests employed by ophthalmologists, examine results obtained using similar imaging modalities, and identify recurring limitations to propose recommendations for future work. We conducted a systematic literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines across four databases: Google Scholar, PubMed, ScienceDirect, and the Cochrane Library. We targeted studies published between 2020 and 2025 and applied predefined inclusion criteria to select 30 original peer-reviewed articles. We then analyzed each study based on the AI models used, development strategies, diagnostic performance, correlation with clinical parameters, and reported limitations. The imaging modalities covered include videokeratography, smartphone-based imaging, tear film interferometry, anterior segment optical coherence tomography, infrared meibography, in vivo confocal microscopy, and slit-lamp photography. Across modalities, deep learning models (e.g., U-shaped Convolutional Network (U-Net), Residual Network (ResNet), Densely Connected Convolutional Network (DenseNet), Generative Adversarial Networks (GANs), transformers) demonstrated promising performance, often matching or surpassing clinical assessments, with reported accuracies ranging from 82% to 99%. However, few studies performed external validations or addressed inter-expert variability. The findings confirm AI’s potential in DED diagnosis, but emphasize gaps in data diversity, clinical use, and reproducibility. It offers practical recommendations for future research to bridge these gaps and support AI deployment in routine eye care. Full article

The spotted seal (Phoca largha), the only pinniped species capable of natural breeding in Chinese waters, serves as a flagship species for the Bohai Sea and the Yellow Sea marine ecosystems. Changes in its population numbers are an important indicator of the status of the marine ecological environment. However, when using traditional monitoring methods, such as telescope inspections and routine unmanned aerial vehicle (UAV) photography, it is difficult to accurately grasp the changes in spotted seal populations. Here, we document the use of infrared imaging with a UAV to facilitate round-the-clock monitoring of spotted seal numbers in a protected area. This approach revealed that late night and early morning (22:00–05:00) were peak times for their haul-out activity, with a maximum count of 166. This provides a new idea for the investigation and monitoring of marine mammals and the protection of marine ecosystems. Full article

There has been an increasing demand for high-resolution image sensing technologies in recent years due to their diverse and advanced optical applications. With recent advances in nanofabrication technologies, this can be achieved through the realization of high-density pixels. However, the development of high-density and miniaturized pixels introduces challenges to the conventional color filters, which generally transmit and absorb different spectral components of light. A significant portion of the incident light is inherently lost using conventional color filters. Moreover, as the pixel size is shrunk, optical losses appear to be substantial. To address these fundamental limitations, a novel nanophotonic optical router is proposed in this work. Our router utilizes a single-layer, all-dielectric metasurface as a spectral router. The metasurface is designed through an inverse design approach that exploits adjoint sensitivity analysis. A novel figure of merit is developed and incorporated in the inverse design process, enabling the metasurface design to effectively sort and route the incoming light into four targeted channels, each corresponding to a distinct spectral component—red, green, blue, and near-infrared. We demonstrate that the proposed quad-spectral metasurface router, having a compact footprint of $2 \mathsf{\mu }\mathrm{m}\times 2 \mathsf{\mu }\mathrm{m}$, achieves an average optical efficiency of approximately 39% across the broad spectral range, i.e., 400–850 nm, with each spectral channel exceeding an efficiency of 25%. This surpasses the maximum efficiency attainable by the conventional four-channel color filters. Our proposed quad-spectral metasurface router offers a wide range of applications in low-light imaging, image fusion, computational photography, and computer vision. In addition, this work highlights the applicability of an adjoint-based inverse design approach to accelerate the development of compact, efficient, and high-performance nanophotonic devices for the next generation of imaging and sensing systems. Full article

During UAV aerial photography tasks, influenced by flight altitude and imaging mechanisms, the target in images often exhibits characteristics such as small size, complex backgrounds, and small inter-class differences. Under single optical modality, the weak and less discriminative feature representation of targets in drone-captured images makes them easily overwhelmed by complex background noise, leading to low detection accuracy, high missed-detection and false-detection rates in current object detection networks. Moreover, such methods struggle to meet all-weather and all-scenario application requirements. To address these issues, this paper proposes DVIF-Net, a visible-infrared fusion network for small-target detection in UAV aerial images, which leverages the complementary characteristics of visible and infrared images to enhance detection capability in complex environments. Firstly, a dual-branch feature extraction structure is designed based on YOLO architecture to separately extract features from visible and infrared images. Secondly, a P4-level cross-modal fusion strategy is proposed to effectively integrate features from both modalities while reducing computational complexity. Meanwhile, we design a novel dual context-guided fusion module to capture complementary features through channel attention of visible and infrared images during fusion and enhance interaction between modalities via element-wise multiplication. Finally, an edge information enhancement module based on cross stage partial structure is developed to improve sensitivity to small-target edges. Experimental results on two cross-modal datasets, DroneVehicle and VEDAI, demonstrate that DVIF-Net achieves detection accuracies of 85.8% and 62%, respectively. Compared with YOLOv10n, it has improved by 21.7% and 10.5% in visible modality, and by 7.4% and 30.5% in infrared modality, while maintaining a model parameter count of only 2.49 M. Furthermore, compared with 15 other algorithms, the proposed DVIF-Net attains SOTA performance. These results indicate that the method significantly enhances the detection capability for small targets in UAV aerial images, offering a high-precision and lightweight solution for real-time applications in complex aerial scenarios. Full article

Background/Objectives: Sturge–Weber syndrome (SWS) is a rare neuro-oculocutaneous disorder characterized by leptomeningeal angioma, naevus flammeus, and ocular manifestations, including diffuse choroidal hemangioma (DCH). This study compares the diagnostic performance of near-infrared reflectance (NIR) imaging and enhanced depth imaging spectral-domain optical coherence tomography (EDI-SDOCT) with fundus photography in detecting DCH. Methods: Seventeen patients with SWS underwent comprehensive ophthalmologic evaluation, including fundus photography, NIR, and EDI-SDOCT imaging. Sensitivity, specificity, and accuracy of fundus photography, NIR, and EDI-SDOCT were calculated. Results: Sixteen patients had evaluable data. DCH was identified by fundus photography in five (31%), NIR in three (18.75%), and EDI-SDOCT in fourteen patients (87.50%). EDI-SDOCT alone demonstrated 100% sensitivity and 100% accuracy, outperforming both NIR (21.4% sensitivity; 31.6% accuracy) and fundus photography (35.7% sensitivity; 43.8% accuracy). When positive findings on NIR and/or SDOCT were combined, sensitivity and accuracy reached 100%. EDI-SDOCT provided detailed morphologic visualization of the choroid, allowing for early diagnosis of DCH even in pediatric cases with limited patient cooperation. Conclusions: EDI-SDOCT significantly improves the detection of DCH in SWS compared with fundus photography and NIR. Given its superior sensitivity and accuracy, incorporating EDI-SDOCT into routine clinical assessment may enable earlier diagnosis and reduce retinal complications in SWS. Full article

Religious panel paintings (icons) play a pivotal role in the rituals of the Eastern Orthodox Christian Church. However, their continuous use often results in physical degradation, prompting remedial interventions. Quite commonly, alterations were treated by simply applying new paint layers directly over the decayed original, while in some cases, old icons were overpainted merely as a means to renovate and modernize them. Therefore, numerous overpainted icons are currently housed in churches, museums, and private collections across Greece. This study focuses on the investigation of a post-Byzantine icon of Christ Pantokrator, which displays extensive overpainting while retaining a few visible fragments of the original composition. The objective was to assess the extent and condition of preservation of the original artwork, to identify materials and techniques used both in the initial painting and in subsequent restoration phases, and to distinguish between those phases. To achieve these aims, a fully non-invasive diagnostic methodology was implemented, including visible light photography, ultraviolet radiation imaging (UVR/UVL), hyperspectral imaging (MuSIS HS), infrared reflectography (IRRef), X-ray radiography, and macroscopic X-ray fluorescence scanning (MA-XRF). The findings confirm that the original painting remains substantially preserved and is of high artistic quality. Moreover, analysis revealed at least two distinct phases of overpainting, likely dating from the 20th century, while the results suggest that the original artwork probably dates to the first half of the 18th century. The study highlights the need to use complementary techniques in order to non-invasively assess complex artifacts like overpainted icons and offers valuable insights into historical restoration practices providing foundation for future conservation planning. Full article

Microwave-assisted rock fragmentation has been considered as one of the most promising technologies in rock excavation, but due to the fact that excavation is usually carried out in water-rich environments, understanding the dynamic fracture properties of rocks with different water contents after microwave irradiation is thus desirable. This study employed an enhanced split Hopkinson pressure bar (SHPB) system to perform dynamic fracture tests on pre-cracked semi-circular bending (SCB) specimens. It systematically explores the changes in the mechanical properties of sandstone under both dry and saturated conditions after exposure to 700 W of microwave radiation for 10 min. Infrared thermal imaging was utilized to capture the temperature distribution across the specimens, while digital image correlation (DIC) and high-speed photography were used to simultaneously record the crack propagation process. Based on the principle of energy conservation, the analysis of energy dissipation during fracture was performed, and the micro-damage evolution mechanism of the material was revealed through scanning electron microscopy (SEM). The results demonstrated that saturated sandstone exhibited a more rapid heating response and significantly lower dynamic fracture toughness and fracture energy compared to dry samples after microwave irradiation. These findings indicate that water saturation amplifies the weakening effect induced by microwaves, making the rock more susceptible to low-stress fractures. The underlying damage mechanisms of microwave radiation on water-bearing sandstone were interpreted with the theory of pore water pressure and structural thermal stresses. Full article