Laser Imaging Research Articles

Structure-function correlation of retinal photoreceptors in PRPH2-associated central areolar choroidal dystrophy patients assessed by high-resolution scanning laser imaging and microperimetry.

High Magnification Module (HMM™, Heidelberg Engineering, Heidelberg, Germany) imaging is a novel technique, designed to visualize the retina at a cellular level. To assess the potential of HMM™-based metrics as endpoints for future trials, we evaluated correlations between structural HMM™ cone metrics, spectral-domain OCT (SD-OCT, Heidelberg Engineering, Heidelberg, Germany) and retinal sensitivity on microperimetry (MP, MAIA, CenterVue, Padova, Italy) in healthy subjects and p.(Arg142Trp) PRPH2-associated Central Areolar Choroidal Dystrophy (CACD) patients. We projected a default 10° MP grid on composite HMM™ images and performed automated cone density (CD), intercell distance (ICD) and nearest neighbour distance (NND) analysis at stimuli located at 3° and 5° retinal eccentricity. We manually measured intrasubject outer retinal thickness on SD-OCT in absolute and relative scotomas, located outside of focal atrophy. We included 15 CACD patients and five healthy subjects. We found moderate-to-strong correlations of HMM™ metrics and MP sensitivity at 3° eccentricity from the fovea. We found the outer retina at the locations of absolute scotomas to be statistically significant thinner (p = 0.000003, one-sample t-test), as the outer retinal thickness at locations of relative scotomas. Interestingly, HMM™ metrics of these areas did not differ significantly. We found significant correlations between structural photoreceptors metrics on HMM™ imaging and retinal sensitivity on MP in healthy subjects and CACD patients. A multimodal approach, combining SD-OCT, MP and HMM™ imaging, allows for detailed mapping of retinal photoreceptor integrity and restitution potential, important data that could serve as biomarkers in future clinical trials.

A human-centric system combining smartwatch and LiDAR data to assess the risk of musculoskeletal disorders and improve ergonomics of Industry 5.0 manufacturing workers

More than one in four workers reportedly suffer from back pain worldwide, leading to 264 million work days lost yearly. In the U.S. alone, it causes $50 billion in healthcare costs every year, up to $100 billion if including decreased productivity and lost wages. The upcoming Industry 5.0 revolution will introduce human-centric manufacturing systems where workers’ well-being comes first while safeguarding their rights: privacy, autonomy, and human dignity. This paper presents a privacy-preserving system based on artificial intelligence that tracks the posture of assembly/disassembly line workers while performing typical standardized tasks on repeat: connecting and separating parts; screwing and unscrewing using an electric screwdriver; tin soldering and unsoldering. The proposed solution assesses the upper-body (dominant arm, dominant shoulder, and trunk) and lower-body (legs) postures according to the ISO 11226 European standard, based on inertial data recorded by a smartwatch and using Laser imaging Detection and Ranging (LiDAR), respectively. These techniques preserve privacy as they collect data that cannot reveal the worker’s identity or sensitive information. Experiments showed that the system recognized a worker’s posture with a mean accuracy close to 98%. The system could help detect bad posture habits and reduce the chances of musculoskeletal disorders while preserving the workers’ privacy, in compliance with the upcoming Industry 5.0 paradigm.

Laser resolidification of Al-5Mg-0.1Sc alloy: Growth of cells and banded structures

The versatility of Al-Mg alloys makes them well-suited for applications ranging from everyday items to cutting-edge fields like automotive, microelectronics, and aerospace. Moreover, although Al-Mg alloys hold promise for improved surface features in components, research on their laser surface remelting (LSR) remains scarce, presenting an open opportunity to create novel components with these materials. Understanding the growth modes and morphologies of laser surface remelted products is critical in this context. Using a laser instrument, optical microscopy, SEM, XRD, Vickers hardness and image analysis techniques, a correlative analysis of microstructure features and laser heat input is proposed in this research. Furthermore, the Al-5Mg-0.1Sc (wt%) alloy was remelted using two distinct original substrates, each exhibiting varying degrees of microstructure coarsening. Additionally, four distinct laser heat input conditions were applied to each case. All molten pools regions were formed either by cells or bands, with higher growth rates producing a higher fraction of bands. While the variation in the original microstructure of the substrate did not significantly impact both cellular spacings and band/cellular fractions, the microhardness varied remarkably with the reduction in energy input from 10.0 J/mm to 1.7 J/mm. Kurz and Fisher model provided an accurate prediction of the cell spacings formed at the laser molten pool.

OPTIMIZING WOUNDED ARTICULAR CARTILAGE FOR IMPROVED CARTILAGE INTEGRATION: EVALUATING CHONDROPROTECTIVE MEASURES FOR MINIMIZING IN SITU CHONDROCYTE DEATH

AbstractObjectiveThe preparation of host degenerate cartilage for repair typically requires cutting and/or scraping to remove the damaged tissue. This can lead to mechanical injury and cartilage cell (chondrocytes) death, potentially limiting the integration of repair material. This study evaluated cell death at the site of cutting injury and determined whether raising the osmotic pressure (hyper-osmolarity) prior to injury could be chondroprotective.MethodsEx vivo human femoral head cartilage was obtained from 13 patients (5 males and 8 females: 71.8 years old) with Ethical Permission and Patient consent. Cartilage wells were created using 3 or 5mm biopsy punches. Cell death at the wounded edge of the host cartilage and the edge of the extracted explants were assessed by quantifying the percentage of cell death (PCD) and measuring the width of the cell death zone at identified regions of interest (ROI) using the confocal laser scanning microscopy and image analysis software. To assess the chondroprotective effect of hyper-osmolarity, cartilage specimens were incubated in 340 or 600mOsm media, five minutes prior to injury to allow the chondrocytes to respond to the altered osmolarity. Wounded cartilage explants and cartilage wells were then cultured for a further 150 minutes following injury.ResultsIn 340mOsm media, the PCD around the 3mm cartilage wells was significantly less compared to the corresponding explants (20.05±10.24% vs 35.25±4.86%; P=0.0003). When using the 5mm biopsy punch, the PCD at the wound edges was significantly lower when compared to the 3mm cartilage wells (13.33±7.80% vs 20.05±10.24%; P=0.0121) at the same osmolarity. The width of the cell death zone for the well edges for both 3 and 5mm punches was significantly narrower when compared to their corresponding harvested cartilage explants in 340mOsm media (P<0.0001; P=0.0218, respectively). Exposing cartilage to raised osmolarity (600mOsm) prior to injury significantly reduced the PCD for cartilage wells produced by the 3mm biopsy punches (from 20.05±10.24% to 12.24±6.00%; P=0.0025). In addition, the zone of cell death was marginally reduced at the edges of the 5mm cartilage wells (19.25±15.78mm to 12.72±9.09mm; P=0.0499).ConclusionsThe choice of biopsy punch and the osmolarity of the incubation medium prior to cartilage injury markedly affected the extent of chondrocyte death both at the edges of the cartilage wells and the explants. The smaller biopsy punch caused more chondrocyte death in the native cartilage wells compared to the larger punch, but this could be compensated for by the chondroprotective effect of raising the osmotic pressure. In general, there was less cell death at the wounded edges of the cartilage wells, compared to the explants. These results suggest that there is scope for further optimising the cutting implements used to create the cartilage wells and protecting chondrocytes by hyper-osmolarity in order to minimize cell death at cut edges and potentially enhance integration between cartilage repair material and host cartilage.Declaration of Interest(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Pulsed swept-source FDML-MOPA laser with kilowatt picosecond pulses around 1550 nm.

Swept-source lasers are versatile light sources for spectroscopy, imaging, and microscopy. Swept-source-powered multiphoton microscopy can achieve high-speed, inertia-free point scanning with MHz line-scan rates. The recently introduced spectro-temporal laser imaging by diffractive excitation (SLIDE) technique employs swept-source lasers to achieve kilohertz imaging rates by using a swept-source laser in combination with a diffraction grating for point scanning. Multiphoton microscopy at a longer wavelength, especially in the shortwave infrared (SWIR) region, can have advantages in deep tissue penetration or applications in light detection and ranging (LiDAR). Here we present a swept-source laser around 1550 nm providing high-speed wavelength agility and high peak power pulses for nonlinear excitation. The swept-source laser is a Fourier-domain mode-locked (FDML) laser operating at 326 kHz sweep rate. For high peak powers, the continuous wave (cw) output is pulse modulated to short picosecond pulses and amplified using erbium-doped fiber amplifiers (EDFAs) to peak powers of several kilowatts. This FDML-master oscillator power amplifier (FDML-MOPA) setup uses reliable, low-cost fiber components. As proof-of-principle measurement, we show third-harmonic generation (THG) using harmonic nanoparticles at the 10 MHz pulse excitation rate. This new, to the best of our knowledge, laser source provides unique performance parameters for applications in nonlinear microscopy, spectroscopy, and ranging.

EXTH-30. GOLD NANOSTARS OBVIATE LIMITATIONS TO LASER INTERSTITIAL THERMAL THERAPY (LITT) AND ENHANCE THE POST-LITT IMMUNE RESPONSE

Abstract Laser interstitial thermal therapy (LITT) is a minimally-invasive technique for the treatment of intracranial tumors that uses a stereotactically-guided laser and real-time magnetic resonance imaging (MRI) to monitor ablation progress. Previous applications of gold nanostars (GNS) in laser ablation of tumors have studied extracranial tumors only and utilized externally administered near infrared radiation that cannot penetrate the cranial compartment. Herein, we present a novel platform for employing GNS in intracranial tumors. We developed non-toxic GNS that exhibit maximum photothermal effects at the 1064 nm laser wavelength used in the FDA-approved clinical Neuroblate® LITT system. Monte Carlo simulations demonstrate that our GNS can accelerate and focus thermal energy distributions. Using ex vivo tumor phantom models, we found that GNS-infused phantoms demonstrate more rapid heating and improved spatial conformation of thermal energy, with neighboring material exposed to lower temperatures than controls. In our intracranial CT-2A glioma model, we quantified accumulation of radiolabeled GNS in tumor tissue via PET/CT. As further validation of tumor-selective GNS accumulation, we used two-photon luminescence to show that GNS selectively accumulate and are retained in intracranial tumors at 24 and 72 hours post-injection. We then utilized our in vivo heterotopic CT-2A model to assess the capacity of systemically-delivered GNS to augment laser ablation; we were able to achieve higher ablation temperatures and more efficient temperature ramping with LITT+GNS. Finally, we explored the potential of LITT+GNS to synergize with immunotherapy to further enhance the post-ablation immune response and found that combination therapy resulted in improved tumor control and immunologic memory that was protective against tumor rechallenge. These results support the ability of GNS to optimize LITT for the treatment of intracranial tumors by improving efficiency and safety, and illustrate the potential of this platform to synergize with immunotherapy.

Evaluation of Laser Image Enhancement and Restoration for Underwater Object Recognition

Evaluation of Laser Image Enhancement and Restoration for Underwater Object Recognition

Optique adaptative : correction des effets de la turbulence atmosphérique sur les images astronomiques

Today, adaptive optics (AO) is installed on all very large astronomical telescopes. It allows to overcome the limitation in angular resolution imposed on large ground-based telescopes by the atmospheric turbulence perturbations. This review paper presents the state of the art of the field for astronomical applications. It gives the principles of AO and describes its main components which are the deformable mirrors, the wavefront sensors and the control algorithms. The paper also presents the main recent achievements and ongoing projects. First, for the direct imaging of extra-solar planets by extreme AO and coronography, taking as example the SPHERE instrument. Then to solve the problem of the very limited sky coverage by using laser guide star and to extend the AO correction beyond the isoplanatic patch. Thus, the various laser-assisted tomographic AO concepts are presented with examples of each realization as for the laser tomography AO, the multi-conjugate AO and the multi-object AO. Finally, the challenges of the new generation of giant telescopes are discussed at the end of the paper with a particular focus on the European Extremely Large Telescope (ELT) project.

An affine transform center line extraction and discontinuity deviation correction method for non-orthogonal grid laser

The extraction of the laser center line is one of the key steps of laser scanning, which is related to the accuracy of the coordinate calculation. Non - orthogonal grid laser scanning has the advantages of a large measuring range and small translation error. For the extraction of the center line of the laser cross region of non-orthogonal grid, the discontinuity and deviation of the results obtained by the existing methods will cause the error of center line coordinate extraction. To solve these problems, according to the properties of image affine, an improved method of laser center extraction for non-orthogonal grid is proposed in this paper. Firstly, the image is divided into sub-images by affine transformation according to slopes, and the orthogonal grid laser image is obtained. Secondly, in order to solve the problem of centerline discontinuity, the orthogonal grid laser image was rotated 0° and 90°, and the Steger method was used to process images. Inverse affine transformation is performed on the results. Finally, the sub-images are clipped and splicing according to slopes, and the two rotation results are union to get the complete laser center line. By comparing various methods and 3D reconstruction experiments, the accuracy of the proposed method is verified in the center line extraction of grid laser cross-region.

Endoscopic features with linked-color imaging of non–Helicobacter pylori Helicobacter-associated gastritis: a case study

Background and aimsThe endoscopic findings of non-Helicobacter pylori Helicobacter (NHPH) are not widely known. Linked color imaging (LCI) has emerged as a new system for image-enhanced endoscopy (IEE) that enhances color tone and improves visibility. The aim of this case study was to assess how endoscopic findings of NHPH are enhanced with LCI. MethodsWe report a case of a 72-year-old woman in whom an NHPH species was found during esophagogastroduodenoscopy (EGD) using LCI. ResultsThe EGD did not reveal any endoscopic findings of diffuse redness, patchy redness or atrophy. However, erosions, non-uniform redness, and crack-like mucosa were seen in the antrum, and LCI enhanced endoscopic findings. In addition, nodular gastritis and a white marbled appearance were also observed in the antrum; LCI and blue laser imaging enhanced endoscopic findings. Floating bacterial bodies with a fine coil-like shape and diameter longer than that of H. pylori were pathologically observed in the mucus suggesting NHPH. A PCR test led to a diagnosis of Helicobacter suis. ConclusionsOur case demonstrates that IEE is useful in diagnosing NHPH. The detection of NHPH using IEE enabled us to contribute to an improved diagnosis of NHPH.

Investigation of the wake region behind a hemispherical turret via laser Rayleigh scattering.

Planar and volumetric density measurements in the wake region behind a mounted hemispherical turret are obtained using laser Rayleigh scattering. The measurements are conducted in a Mach 2 wind tunnel facility at the Kirtland Air Force Base. Quantitative measurements of density and contour plots with lines of constant density are computed, thus enabling visualization of the turret wake's fluid dynamics. A new, to the best of our knowledge, laser diagnostic methodology and configuration for capturing laser images is also presented. This methodology enables further suppression of background light scattering. Multi-dimensional single-shot and time-average measurements are recorded at multiple axial locations behind the turret. The images acquired reveal turbulent regions of the wake flow, and a discussion of the observed phenomena is presented.

INTEGRATION OF IPHONE LiDAR WITH QUADCOPTER AND FIXED WING UAV PHOTOGRAMMETRY FOR THE FORESTRY APPLICATIONS

Abstract. The recent innovations in remote sensing technologies have given rise to the efficient mapping and monitoring of forests. The developments in the sensor implementation have mainly focused on optimizing the payload of the UAV system and allowed the users to acquire the data simultaneously with a range of active and passive sensors like high-resolution RGB cameras and multispectral cameras LiDAR (Laser Imaging Detection and Ranging). The main objective of this research contribution is to combine the Digital Elevation Model (DEMs) from quadcopter Unmanned Aerial Vehicles (UAVs), Fixed Wing UAV-based cameras, and iPhone datasets for the forest plots. The datasets from two vegetation seasons, namely leaf-off and leaf-on, were used to combine the Digital Elevation Models from different data acquisition platforms. This internship research work aims to create and experiment with new methods, techniques, and technologies for the applications of UAV photogrammetry and iPhone LiDAR in forest napping and inventory management. CHMs are also generated in this work which helps assess the conditions of the forests in the recreational areas, and the possibility of solutions like iPhone LiDAR and UAV photogrammetry would be highly efficient and economical. The leaf-off and leaf-on datasets were processed in Agisoft Metashape Professional software to generate dense point clouds for the forest plots. The point cloud from the leaf-on dataset was rasterized to generate a DSM whereas the leaf-off point cloud generated a DSM of the forest plots after ground filtering with Cloth Simulation Filter (CSF) plugin. The iPhone LiDAR point was also rasterized to a DTM product after pre-processing steps and noise removal. The Canopy Height Models (CHMs) were generated by subtracting UAV and iPhone LiDAR based DTMs from the UAV leaf on DSM. Finally, the accuracy assessment of CHMs from UAB datasets and their integration with iPhone LiDAR has been assessed using the accurate tree heights measured during the forest field visits. The proposed methodology can be used for forest mapping purposes where a moderate accuracy is requested.

Experimental and numerical investigation of damage and mechanical property retention by bio-composite plastic made with flax or pinewood fiber and aged by exposure to ultraviolet light

The objective of this study was to compare two types of natural short fibers, one lignin-rich and one lignin-poor, as reinforcing filler of bio-composite plastic in accelerated aging experiments. Short natural-fiber-reinforced plastic composites of flax fiber or pinewood fiber (30 % by weight) were injected and then exposed to ultraviolet (UV) light with and without moisture for up to 1440 h. Color, roughness, and mechanical properties were then evaluated using colorimetry, confocal laser imaging, tensile tests, and drop-weight tests. Damage to the bio-composites was monitored using the acoustic emission technique during tensile testing. The response during impact tests was simulated using the finite element method. Results showed that flax-fiber-reinforced polypropylene exhibited superior properties before aging, but experienced greater loss of these properties after aging, particularly under moist conditions. The numerical model was found to be in good agreement with the experimental results.

Testing of Long-Term Stability of Metrological Characteristics of the CLWS-300 Laser Image Generator

Testing of Long-Term Stability of Metrological Characteristics of the CLWS-300 Laser Image Generator

S1879 Diagnostic Performance of Blue Laser Imaging for Gastric Cancer: A Systematic Review and Meta-analysis

S1879 Diagnostic Performance of Blue Laser Imaging for Gastric Cancer: A Systematic Review and Meta-analysis

Комп’ютерний сингулярний аналіз процесів лазерної автофлуоресценції двопроменезаломлюючих біологічних тканин

The analytical conditions for the formation of singularities of the Jones matrix elements of birefringent networks of biological tissues are determined. The correlation between coordinate positions of characteristic points of two-dimensional elements of the Mueller matrix of an optically thin layer of biological tissue and the network of S- and C-points in its laser image is established. The effectiveness of the Mueller matrix singular diagnostics of not only oncological changes in the myometrial tissue, but also the differentiation of their severity is demonstrated.

Кореляційно-фазовий інтелектуальний аналіз комплексного ступеню когерентності лазерних автофлуоресцентних зображень плазми крові та діагностика онкологічних змін органів людини

The theoretical foundations of correlation-phase analysis of laser images of human blood plasma are presented. The values and ranges of change of statistical (moments of the 1st - 4th orders), correlation (Gram-Charlier decomposition coefficients of autocorrelation functions) and fractal (slopes and variance of extremes of logarithmic dependences of power spectra) parameters of the coordinate distributions of CSP are investigated. The objective criteria for diagnosing oncological changes in the blood plasma of a cancer patient are determined.

Enhancing Maritime Safety and Efficiency: A Comprehensive Sea Fog Monitoring System for Ningbo Zhoushan Port

Sea fog poses a considerable challenge to port operations, impacting maritime safety and efficiency. During the past five years, the average annual downtime of the navigation dispatch department in Ningbo Zhoushan Port due to weather was 800–1000 h, of which approximately 300 h can be attributed to sea fog. This study addresses the issue by developing a comprehensive sea fog monitoring system for Ningbo Zhoushan Port. The system utilizes automatic weather stations (AWS) and visibility laser imaging, detection, and ranging (LIDAR) to assess sea fog severity and improve monitoring accuracy. By increasing monitoring frequency and adopting corresponding warning measures, the system aims to enhance maritime safety and efficiency in Ningbo Zhoushan Port. The results showed that the implemented system successfully determines sea fog severity, enables real-time monitoring, and provides precise visibility assessments. Joint assessments revealed a substantial increase in the annual operating time and revenue of the port. These findings underscore the importance of advanced monitoring techniques in optimizing port operations, reducing collision risks, and mitigating economic losses caused by sea fog.

Інтелектуальна система оцінювання ступеня локальної деполяризації полів лазерної автофлуоресценції двопроменезаломлюючих мереж протеїнових кристалів

The theoretical foundations of the description of scattered coherent radiation fields using a new correlation parameter - the degree of local depolarization (DLD) - are presented. The data of measuring the coordinate distributions of the DLD of laser images of healthy and pathologically altered rat skin are presented. The values and ranges of change of statistical (moments of the 1st - 4th orders), correlation (correlation area) and fractal (slopes and variance of extremes of logarithmic dependences of power spectra) parameters of the coordinate distributions of the DLD are investigated. The objective criteria for diagnosing oncological changes in the structure of the rat skin are determined.

A study of error correction method based on selective focus for curved rail profile measurement

Rail profile detection is an important means of railway operation and maintenance. Currently, structured light profile measurement technology is mainly used for vehicle-mounted rail profile measurement. The body attitude of the vehicle will change as it passes by a curve, and the laser plane of the rail profile measurement device would be non-perpendicular to the rail in the local longitudinal direction, resulting in errors in rail profile measurement. To address this issue, an error correction method based on selective focus for curved rail profile measurement is proposed. The virtual 3D rail is generated with the section image of a single-beam laser and projected onto the image plane, which is then combined with the projection data of virtual 3D rail and the actual rail from the rail image to build the optimization function. The optimal auxiliary plane perpendicular to the rail’s longitudinal direction is then determined. Finally, error correction is achieved by projecting the measured data onto the optimal auxiliary plane. The effectiveness and accuracy of the proposed method are validated through experiments, demonstrating that regardless of the laser plane’s relative pitch or yaw motion with respect to the rail, the corrected profile wear measurement error was under 0.10 mm, satisfying the requirement for rail wear measurement accuracy. In this study, the plane perpendicular to the longitudinal direction of the rail was obtained through selective focus, thus providing a new insight into future work on rail profile measurement error correction.