Optical Scanning Research Articles

Snapshot infrared Fourier transform imaging spectrometer for transient dynamic sensing

Imaging spectroscopy is an effective method for simultaneously acquiring the spatial information distribution and the spectral fingerprint characteristics of a target. Implementing dynamic target spectral mapping through optical scanning may lead to image artifacts and spectral interference. This paper proposes an innovative structure for a snapshot infrared Fourier transform Imaging spectrometer (SIFTIS), which utilizes a stepped micro-mirror and a lens array, combining the advantages of snapshot imaging spectroscopy and infrared spectral detection. The SIFTIS technology acquires a complete three-dimensional dataset within a single integration time, featuring good stability, strong real-time capability, and high spatiotemporal resolution. It has significant advantages in fields such as camouflage target recognition and harmful and pollutant gas measurement. Firstly, the optical field transmission model of SIFTIS was constructed, and the system's error propagation model was further deduced. The impact of the optical system and core optical components’ aberration residues and positional errors on spectral mapping were analyzed, providing design error tolerance. Subsequently, preliminary experiments combined with simulation analysis were used to calibrate and correct the spectral shifts caused by rotation, pitch, and roll component errors of the stepped micro-mirrors reflective surfaces at various levels. Finally, imaging spectral detection of dynamic plume targets was conducted to demonstrate the desired results and feasibility.

A Semi-Automated Machine-Learning Tool for Assessing Building Phases: Discriminant Analysis of Mortars from the 2022 Excavation at the Sarno Bath Complex in Pompeii

This study presents the results of the analyses of 15 structural mortars from the building at civ. 21, level +0 of the Sarno Bath complex in Pompeii. These samples were collected during recent stratigraphic excavations (year 2022) for detailed in-laboratory compositional characterization, aiming to trace the construction phases of the originating walls. The 2022 samples were firstly analyzed via quantitative phase analysis–X-ray powder diffraction. The resulting quantitative mineralogical profiles were then processed alongside those analyzed in previous studies from level +0 structures of the Sarno Baths using multivariate statistical methods, including principal component analysis (PCA) and discriminant analysis, applied to quantitative phase analysis (QPA)–X-ray powder diffraction data (XRPD), to identify and map the construction phases. This approach enabled the correlation of the 2022 samples with previously established construction phases. Polarized-light optical microscopy and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) were then primarily used for validation purposes. These methods highlighted the compositional differences between samples and revealed significant features related to the use of specific raw materials. These results confirm the reliability of the semi-automated sample processing proposed in this research, adopting discriminant analysis as a machine-learning-based tool for defining construction phases in Pompeian contexts.

Optically Readable Multilevel Magnetic Memory States in Perpendicularly Exchange-Biased Ferromagnetic Multilayers.

The construction of multilevel magnetic states using materials with perpendicular magnetic anisotropy (PMA) offers a novel approach to enhancing the storage density and read/write efficiency of nonvolatile magnetic memory devices. In this study, optically readable multilevel magnetic domain states are achieved by inducing asymmetric interlayer interactions and decoupling the magnetic reversal behavior of individual ferromagnetic (FM) layers in exchange-biased FM multilayers with PMA. Hepta-level magnetic domain states are formed in [Co/Pt]n FM multilayers grown on an antiferromagnetic Fe2O3 layer within a relatively low magnetic field range of ∼±400Oe. Raising and lowering operations between states are demonstrated to be achievable, enabling the writing of new information without the need for initialization in multilevel magnetic memory applications. This design concept, leveraging multilevel magnetic domain states and facilitating noncontact optical reading of stored information, demonstrates the potential to enhance the storage density of nonvolatile magnetic memory devices as it eliminates the need for electrical circuits typically required in other resistive memory technologies.

An In Vivo Biostability Evaluation of ALD and Parylene-ALD Multilayers as Micro-Packaging Solutions for Small Single-Chip Implants.

Miniaturization of next-generation active neural implants requires novel micro-packaging solutions that can maintain their long-term coating performance in the body. This work presents two thin-film coatings and evaluates their biostability and in vivo performance over a 7-month animal study. To evaluate the coatings on representative surfaces, two silicon microchips with different surface microtopography are used. Microchips are coated with either a ≈100nm thick inorganic hafnium-based multilayer deposited via atomic layer deposition (ALD-ML), or a ≈6µm thick hybrid organic-inorganic Parylene C and titanium-based ALD multilayer stack (ParC-ALD-ML). After 7 months of direct exposure to the body environment, the multilayer coatings are evaluated using optical and cross-sectional scanning electron microscopy. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is also used to evaluate the chemical stability and barrier performance of the layers after long-term exposure to body media. Results showed the excellent biostability of the 100nm ALD-ML coating with no ionic penetration within the layer. For the ParC-ALD-ML, concurrent surface degradation and ion ingress are detected within the top ≈70nm of the outer Parylene C layer. The results and evaluation techniques presented here can enable future material selection, packaging, and analysis, enhancing the functional stability of future chip-embedded neural implants.

Anatomical and functional changes after internal limiting membrane peeling.

Internal limiting membrane (ILM) peeling has been an acceptable step in vitrectomy surgeries for various retinal diseases such as macular hole, chronic macular edema following epiretinal membrane (ERM), and vitreoretinal traction. Despite all the benefits, this procedure has some side effects, which may lead to structural damage and functional vision loss. Light and dye toxicity may induce reversible and irreversible retina damage, which will be observed in postoperative optical coherence tomography scans. Retinal nerve fiber layer damage is attributed to ganglion cell degeneration and axonal transport alteration, and dissociated optic nerve fiber layer is due to Müller cell damage. Eccentric MHs and recurrence of previous MHs may also lead to vision loss. Iatrogenic retinal damage may cause structural retinal changes without significant vision loss or progression to choroidal neovascularization. The mechanism of persistent macular edema after membrane peeling is still unclear, but it has been related to tractional trauma and blood-retina barrier damage. The reappearance of ERM is another cause of decreased vision after ILM peeling, which might be secondary to incomplete membrane removal. In glaucoma patients, ILM peeling is associated with significantly worsening the mean deviation on the visual field test after the surgery. We discussed various causes of vision loss and structural changes following ILM peeling. These causes may be attributed to the surgical procedure itself or the associated steps, instruments, and dyes used during the ILM peeling procedure.

A Precessing-Coin-like Rotary Actuator for Distal Endoscope Scanners: Proof-of-Concept Study.

This paper presents, for the first time, a rotary actuator functionalized by an inclined disc rotor that serves as a distal optical scanner for endoscopic probes, enabling side-viewing endoscopy in luminal organs using different imaging/analytic modalities such as optical coherence tomography and Raman spectroscopy. This scanner uses a magnetic rotor designed to have a mirror surface on its backside, being electromagnetically driven to roll around the cone-shaped hollow base to create a motion just like a precessing coin. An optical probing beam directed from the probe's optic fiber is passed through the hollow cone to be incident and bent on the back mirror of the rotating inclined rotor, circulating the probing beam around the scanner for full 360° sideway imaging. This new scanner architecture removes the need for a separate prism mirror and holding mechanics to drastically simplify the scanner design and thus, potentially enhancing device miniaturization and reliability. The first proof-of-concept is developed using 3D printing and experimentally analyzed to reveal the ability of both angular stepping at 45° and high-speed rotation up to 1500 rpm within the biologically safe temperature range, a key function for multimodal imaging. Preliminary optical testing demonstrates continuous circumferential scanning of the laser beam with no blind spot caused by power leads to the actuator. The results indicate the fundamental feasibility of the developed actuator as an endoscopic distal scanner, a significant step to further development toward advancing optical endoscope technology.

Enhanced three-dimensional imaging with large depth of field using pre-processing in optical scanning holography

Enhanced three-dimensional imaging with large depth of field using pre-processing in optical scanning holography

Spectroscopic imaging of biological tissue components by non-contact optical scanning based on the detection of ultrasound induced by mid-infrared laser radiation

Spectroscopic imaging of biological tissue components by non-contact optical scanning based on the detection of ultrasound induced by mid-infrared laser radiation

Fluid fluctuations assessed with artificial intelligence during the maintenance phase impact anti-vascular endothelial growth factor visual outcomes in a multicentre, routine clinical care national age-related macular degeneration database

AimTo evaluate the impact of fluid volume fluctuations quantified with artificial intelligence in optical coherence tomography scans during the maintenance phase and visual outcomes at 12 and 24 months in...

Risk and correlates of prolonged grief disorder in bereaved Chinese university students

Bereavement can present significant challenges for university students, yet the proportion at risk of prolonged grief disorder (PGD) remains unclear. This study examined the proportion at risk of PGD and associated factors among Chinese university students. Using an online survey administered to bereaved university students in mainland China (N = 948), 424 students (Mage =21.60, 56.1% female) reported a significant loss for more than 12 months. Chi-squared and t-tests were used to examine associations between PGD risk and related factors. Results showed 14.2% of the sample were at high risk of PGD. The most frequently reported symptoms were a marked sense of disbelief, intense emotional pain, and yearning for the deceased. PGD risk was associated with physical health, age and relationship to the deceased, expectedness and cause of death, resilience, and stress since the loss. Identifying these correlates can inform future prevention or intervention strategies for bereaved university students.

Photopsias are associated with greater levels of depression and anxiety

ABSTRACT Clinical relevance Vitreous floaters have been associated with depressive and anxiety symptoms. However, there is a scarcity in the literature regarding the possible impact of vitreous flashes on the psychological status of the patients. Background Photopsias and vitreous floaters frequently co-exist. Floaters have been accompanied by exacerbated levels of depression and anxiety. The aim of this study was to examine whether the presence of photopsias in patients suffering from vitreous floaters is accompanied by exacerbated levels of anxiety and depression. Methods One hundred and four patients complaining of floaters were included in the study; 51 experienced also photopsias and 53 did not. A comprehensive ocular examination, including funduscopy and optical coherence tomography scans was performed to every patient, while their clinical and demographic data were also assessed. Every participant completed the PHQ-9, the Zung SDS, and the HADS anxiety and depression questionnaires. Results The clinical and demographic data did not differ significantly between the study groups (p > 0.05).The scores of every questionnaire were significantly higher among the patients with vitreous flashes (p < 0.05 for all). After adjustment for several confounders, the values remained significantly impaired. Conclusion Photopsias negatively affect the psychological and mental well-being of the patients, by the terms of amplified levels of depression and anxiety. These findings underscore the necessity for a more holistic approach to managing patients presenting with vitreous flashes.

Random sparse sampling and compressive sensing based reconstruction for computational optical scanning holography

Random sparse sampling and compressive sensing based reconstruction for computational optical scanning holography

Effect of Pre-Emulsified Flaxseed Oil Containing Rutin on the Quality of Nemipterus virgatus Surimi Gel: Gelatinization Properties, Storage Stability, and Protein Digestibility.

Rinsing during surimi protein processing can result in the loss of essential nutrients, such as fats and minerals. Therefore, supplementing functional fats in a stable form can make up for the fat loss of surimi during the rinsing process. This research aimed to investigate the effects of incorporating pre-emulsified flaxseed oil with different concentrations of rutin (0, 0.5, 1.5, 2.5, and 3.5%, dissolved in flaxseed oil, w/v) to Nemipterus virgatus surimi on the gelatinization properties, lipid oxidation, and in vitro static simulated digestion characteristics of surimi gels. The results indicated that the addition of 1.5% rutin significantly improved the water-holding capacity and decreased the cooking loss rate of surimi gel (p < 0.05). The results of optical microscopy and scanning electron microscopy showed that the addition of 1.5% rutin promoted a denser network structure of surimi gel. Furthermore, the incorporation of rutin effectively slowed lipid oxidation in pre-emulsified flaxseed oil surimi gel. Compared with the gel group containing only pre-emulsified flaxseed oil, the addition of rutin significantly reduced the levels of volatile base nitrogen (TVB-N) and thiobarbituric acid reactive substances (TBARSs) in the gel and also mitigated the decline in acidity (p < 0.05). Moreover, the addition of rutin significantly inhibited the decrease in pH of surimi gel during storage (p < 0.05). In vitro static simulated digestion demonstrated that the addition of 1.5% rutin enhanced the protein digestibility from 71.2% to 77.2% of the surimi gel. Therefore, adding pre-emulsified oil containing an appropriate amount of rutin to surimi can not only compensate for the fat loss during the surimi rinsing process but also effectively improve the quality characteristics of surimi gels. This research will provide a theoretical basis for the effective addition of functional lipids in surimi products and the development of nutritious and healthy surimi products.

Updates on Methods for Body Composition Analysis: Implications for Clinical Practice.

Recent technological advances have introduced novel methods for measuring body composition, each with unique benefits and limitations. The choice of method often depends on the trade-offs between accuracy, cost, participant burden, and the ability to measure specific body composition compartments. To review the considerations of cost, accuracy, portability, and participant burden in reference and emerging body composition assessment methods, and to evaluate their clinical applicability. A narrative review was conducted comparing traditional reference methods like dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI), and computed tomography (CT) with emerging technologies such as smartphone camera applications, three-dimensional optical imaging scanners, smartwatch bioelectric impedance analysis (BIA), and ultrasound. Reference methods like CT and MRI offer high accuracy and the ability to distinguish between specific body composition compartments (e.g., visceral, subcutaneous, skeletal muscle mass, and adipose tissue within lean mass) but are expensive and non-portable. Conversely, emerging methods, such as smartwatch BIA and smartphone-based technologies, provide greater accessibility and lower participant burden but with reduced accuracy. Methods like three-dimensional optical imaging scanners balance portability and accuracy, presenting promising potential for population-level applications. The selection of a body composition assessment method should be guided by the clinical context and specific application, considering trade-offs in cost, accuracy, and portability. Emerging methods provide valuable options for population-level assessments, while reference methods remain essential for detailed compartmental analysis.

Computer-aided design and fabrication of statistically shaped nasal prostheses: A feasibility study.

A nasal prosthesis may compensate for a partial or complete defect of the nose associated with trauma or amputation. However, the design and production is time-consuming, expensive, and expertize-dependent. Computer-generated prosthesis models and 3D printing can optimize the process. The purpose of this pilot study was to evaluate a novel method for nasal prosthesis design utilizing statistical shape modeling (SSM) on a cohort of participants. The prosthesis shapes were generated by a design algorithm and fabricated through a 3-dimensionally (3D) printed mold. Combining a semi-automated algorithm with 3D printing reduced the dependence on expertize. A proof-of-concept assessment was conducted by enrolling 20 participants with total nose amputation with a conventionally created prosthesis (Cp). The faces of the participants were scanned with an optical scanner to acquire 3D surface scans that were loaded into the algorithm to create the statistically shape modeled prosthesis (SSMp). Participants were asked to digitally modify the SSMp by changing 9 parameters using the Scalismo Lab software program, allowing them to shape their preferred nose model, the patient-preferred prosthesis (PPp). The SSMps were fabricated using 3D printed molds and mailed to the participants for testing. They were asked to complete questionnaires comprising three FACE-Q modules: satisfaction with the nose and psychological and social function. In addition, the SSMp and Cp were compared with the PPp using anthropometric measurements. Fifteen participants were able to fit the SSMp and complete the questionnaire. The median satisfaction, psychological, and social function scores were 56, 67, and 62, respectively. All 20 participants filled out the questionnaires on their Cp, with scores of 71, 67, and 62, respectively. Anthropometric measurements comparing the SSMp with the PPp showed that the algorithm generates noses with a wider nasal root, a larger nostril floor width to nasal width ratio, a smaller columella length to nasal width as well as nostril floor width ratio than the patients prefer according to their set PPp. Comparing the Cp with the PPp showed a larger nasal width to nasal height ratio and nasal root width to intercanthal distance ratio. SSM can facilitate the design and fabrication of nasal prostheses. Using the current models, however, patients were less satisfied than with prostheses made by the anaplastologist in consultation with the patient. Improving the SSM algorithm and incorporating patient manipulations into the resulting model should increase patient satisfaction and enable the production of nasal prostheses with minimal expert dependence.

Fracture Resistance and Wear Behavior of Ultra‐Thin Occlusal Veneers Made From Translucent Zirconia Ceramics Bonded to Different Tooth Substrates

ABSTRACTObjectiveInvestigation of the mechanical properties of occlusal veneers made from zirconia with varying translucency, bonded to different tooth substrates.Materials and MethodsSixty‐four extracted molars were divided into two groups: preparation within enamel (E) or extending into dentin (D). Veneers were milled from four zirconia ceramics (n = 8): 5Y‐TZP (HT), a multilayer of 5 and 3Y‐TZP (GT), 3Y‐TZP (LT), and 4Y‐TZP (MT). After bonding, specimens underwent thermocycling (7500 cycles; 5°C–55°C) and chewing simulation (1,200,000 cycles; 10 kg), followed by investigation of the wear behavior using optical and laser scanning microscopy. Specimens were then loaded to examine fracture resistance.ResultsAll specimens except one in the HT group survived artificial aging. Zirconia wear was below the resolution of the 3D scanner, with no significant difference in antagonist vertical loss across materials (p &gt; 0.05). Fracture resistance was significantly higher in E‐LT compared with E‐HT (p = 0.003). No significant differences (p &gt; 0.05) were observed in fracture resistance between materials bonded to dentin, or between the materials within different substrates.ConclusionsVeneers made of 3 and 4Y‐TZP zirconia showed promising in vitro performance and fracture resistance, regardless of the tooth substrate. All zirconia ceramics exhibited favorable wear behavior.Clinical SignificanceAs tooth wear rates increase, the use of minimally invasive occlusal veneers is becoming more important. The goal is to create restorations that are both esthetically pleasing and mechanically durable, while keeping them thin to minimize occlusal preparation and still ensure sufficient fracture resistance. Ultra‐thin (0.3 mm in the fissures/0.6 mm at the cusps) occlusal veneers made of 4Y‐TZP, multilayer and 3Y‐TZP zirconia ceramics survived chewing simulation corresponding 5‐years. All zirconia restorations showed wear‐resistant behavior.

Accuracy of digital and conventional implant impressions in edentulous jaws: A clinical comparative study.

This clinical study aimed to evaluate the accuracy of digital and conventional implant impressions in a fully edentulous maxilla and mandible. A 53-year-old edentulous patient with four maxillary and two mandibular implants was selected. Ten intraoral scans (IOS) and a conventional impression per jaw were taken. Clinically verified upper and lower plaster models were digitized using both optical (reference data, n = 10 per model) and tactile laboratory scanner (n = 10 per model). Accuracy was evaluated by comparing the precision and linear/angular deviations of the implants with the reference data. Statistical analyses were conducted using Student's t-test and Kruskal-Wallis test (α = 0.05). In the maxilla, the most significant linear deviations exceeding the 100 µm threshold were found with IOS between implants 1-4. In the mandible, all linear deviations remained below 55 µm. Angular deviations between implants after IOS ranged from 0.01° to 0.40° in the mandible and <0.01° to 1.86° in the maxilla. After tactile scanning, linear deviations did not exceed 100 µm threshold (except in one distance) and angular deviations ranged from 0.04° to 0.54° (mandible) and <0.01° to 2.50° (maxilla). The optical scanner demonstrated significantly higher precision (p < 0.001) compared to the IOS and tactile scanner. Given the significant deviations observed, especially in the maxilla, the optical scanner following conventional impressions remained the preferred method for fully edentulous cases due to its superior accuracy. IOS could be a viable alternative particularly for shorter distances in the edentulous jaw, although the clinical implications of these deviations need to be investigated in future studies.

Equipmentless point-of-care testing of dengue antibodies using ELISA and smartphones.

Infections with the dengue virus affect more than 100 million people every year. The infected can present a mild form of the disease or a severe form, which can, eventually, lead to death. Dengue prevails in tropical and subtropical regions, although increased incidence has been observed in the last years in tempered climates. Vaccines are available but testing for previous infection is often required prior to application. Commercially available ELISA and rapid tests for the diagnosis of dengue IgG do not fulfill individually the performance required by control agencies. In this context, rapid, simple and decentralized point-of-care testing (POCT) is highly desirable. However, POCT approaches available usually offer expensive solutions, often due to the complex complementary hardware required. In this article, an equipmentless system based on a commercial ELISA kit and a smartphone is developed for POCT of dengue antibodies. A customized app provides guiding, optical reading, result reporting and connectivity. The reading method employes an algorithm which requires no external information, other than the available on the digital images from the smartphone camera, to classify samples into positives, negatives or indeterminates. The full system operation, from sample extraction to result reporting, was tested in a low resource medical facility with real patients (n = 26). After comparison with an ELISA reader, a Cohen's κ coefficient of 0.92 was obtained, showing very good agreement between both methods. These results show that it is possible to perform ELISA with no specific equipment, bringing massive testing at low resource facilities one step closer.

Comparison of tooth substance loss and angle deviation in access cavity preparation using guided endodontics and conventional method in calcified canals – An in vitro study

Abstract Aims: This study aimed to evaluate the accuracy of access cavity preparation using guided endodontics (GE) and conventional technique (CT) in calcified canals. Subjects and Methods: Twenty teeth with calcification up to middle third were collected after scanning through RadioVisioGraphy (RVG). Preoperative cone-beam computed tomography (CBCT) scan was done and samples were randomly divided into two groups of ten samples each on the basis of method of access cavity preparation. Group 1: Access cavity was prepared by CT, Group 2: Access cavity was prepared by GE. 3D template and corresponding guide drill were made for group 2 samples after performing optical surface scans. After access cavity preparation, postoperative CBCT scanning was performed for all samples. The amount of tooth structure loss and angle deviation were calculated using Sidexis Software. Statistical Analysis Used: The data were analyzed using IBM SPSS Statistics, version 22. A t-test compared tooth structure loss and angle deviation between groups, and a one-way ANOVA calculated tooth structure loss in multiple directions for both groups (P &lt; 0.001). Results: Our study found that the mean tooth volume loss (17.19 mm3 ± 06.11 standard deviation [SD]) and angle deviation (4.82° ±01.66 SD) in GE was significantly less (P &lt; 0.001) as compared to mean tooth structure loss (38.85 mm3 ± 19.07 SD) and angle deviation (13.16° ±2.34 SD) by CT. Conclusion: GE is more accurate and conservative than CT in management of calcified canals.

Effect of shape and size of implant scan body on scanning accuracy: an in vitro study.

Objectives: Evaluating the effect of shape and size of implant scan body on the accuracy of optical 3D scanning. Materials and methods: Fifteen PEEK scan bodies were milled, including 1 spherical, 9 cylindrical, and 5 cuboidal. The 3D position and angulation of each scan body were measured using a CMM 3 times and a laboratory scanner 10 times. The linear and angular trueness and precision of the scans were calculated by comparing with the CMM measurements. Results: The linear accuracy of the cylindrical scan bodies (9.5±6.2 µm) was significantly higher than those of the cuboidal (17.7±8.1 µm) and spherical scan bodies (12.5±6.5 µm). The cuboidal (0.050±0.009°) showed significantly better angular accuracy than the cylindrical (0.065±0.040°). In the cylindrical group, the narrow (∅4.8 mm) demonstrated significantly inferior accuracy than the wider (∅5.5 mm and ∅6.5 mm)(p=0.003). The tall (12 mm) showed significantly higher angular trueness than the shorter (8 and 4 mm)(p<0.001). In the cuboidal group, the 24 mm2 exhibited significantly poorer angular trueness compared to the 18 mm2 and 30 mm2 (p<0.001) Conclusions: The shape and size of the implant scan body significantly affect the scanning accuracy. Spherical scan bodies cannot transfer implant angulation. Scan bodies with a size of >∅4.8mm and >8 mm seem accurate for transferring the 3D implant position. Clinical significance: The shape and size of scan bodies directly influence the accuracy of 3D scanning. Well-designed scan bodies offer better transfer results, which is crucial for ensuring passive fit of implant prostheses and improving long-term clinical outcomes.