Angle Images Research Articles

A dense light field reconstruction algorithm for four-dimensional optical flow constraint equation

Dense light field sampling is an important basis for refocusing, depth estimation and 3-D imaging. It is difficult to obtain high resolution dense light field with a large-scale camera array and expensive equipment. At the same time, the current storage devices and transmission bandwidth also limit this technology's post-processing and application. In order to effectively reconstruct the angle domain of the light field based on the sparse light field data, this paper analyzes the correlation and constraint relationship between the optical flow field and the motion field of multi-view images in the same scene, extends the traditional optical flow constraint equation of two-dimensional imaging to the optical flow constraint equation of four-dimensional light field, and establishes an effective mathematical model. The coordinate position of the original pixel in the new angle image is determined by coordinate search, and its intensity is reconstructed. The experimental results of multi-scene dense reconstruction show that the proposed method can reconstruct the texture, shadow and color information in the light field of a long-baseline scene with high quality. The quantitative evaluation results show that the algorithm can be applied to dense light field reconstruction of complex scenes. The algorithm in this paper is only suitable for the case of optical flow constraint in a linear light field, and the follow-up research will focus on the case of nonlinear optical flow constraint.

Saussurea obvallatta leaves extract as a potential eco-friendly corrosion inhibitor for mild steel in 1 M HCl

The extract of saussurea obvallatta leaves (SOLE) has been examined for corrosion inhibition studies for mild steel (MS) in 1 M HCl solution by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and traditional mass change measurements. SOLE controlled maximum of 90 % corrosion rate of MS in 1 M HCl solution at 200 ppm of SOLE. SEM-EDX, AFM and Contact angle images revealed that, MS surface was least affected by the acid solution in presence of SOLE. FT-IR and UV–Visible absorption spectral values established the set of a corrosion defensive layer over the MS surface. Potentiodynamic measurement revealed that SOLE act as a both anodic and cathodic type of inhibitor. Quantum chemical calculations shows that, the EHOMO as an electron donor of SOLE donate electrons to appropriate acceptor molecules to the vacant d orbital of Fe atoms of MS. Un-filled 3d orbital of MS could bind with HOMO of the inhibitors. On the other hand filled 4s orbital could donate the electron to LUMO of the inhibitor as oftenly ELUMO indicates the ability of molecules to accept electrons. Variation of experimental temperature studies revealed that the stability of the protective layer decreased at higher temperature and corrosion activation energies increased in the addition of SOLE.

Sensor fusion in ptychography

Ptychography is a lensless, computational imaging method that utilises diffraction patterns to determine the amplitude and phase of an object. In transmission ptychography, the diffraction patterns are recorded by a detector positioned along the optical axis downstream of the object. The light scattered at the highest diffraction angle carries information about the finest structures of the object. We present a setup to simultaneously capture a signal near the optical axis and a signal scattered at high diffraction angles. Moreover, we present an algorithm based on a shifted angular spectrum method and automatic differentiation that utilises this recorded signal. By jointly reconstructing the object from the resulting low and high diffraction angle images, the resolution of the reconstructed image is improved remarkably. The effective numerical aperture of the compound sensor is determined by the maximum diffraction angle captured by the off axis sensor.

Layered-Cost-Map-Based Traffic Management for Multiple AMRs via a DDS

A traffic management system can be used to control multiple automated mobile robots (AMRs) effectively. This paper proposes traffic management for multiple AMRs based on a layered cost map in ROS 2 for multiple purposes. Using the layered cost map, the new concepts of a prohibition filter, lane filter, fleet layer, and region filter are proposed and implemented. The prohibition filter can help a user set an area that would prohibit an AMR from trespassing. The lane filter can help set one-way directions based on an angle image. The fleet layer can help AMRs share their locations via the traffic management server. The region filter requests for or receives an exclusive area, which can be occupied by only one AMR from the traffic management server. Multiple AMRs communicate via a data distribution service (DDS), which is shared by topics in the same DDS domain. The traffic management server in the domain sends or receives topics to each of the AMRs. The experiments of AMRs under the proposed traffic management show the effectiveness of our approach.

Improved performance of PCBM/MAPbI3 heterojunction photovoltaic cells with the treatment of a saturated BCP/IPA solution

The interfacial contact quality between the hydrophilic MAPbI 3 and hydrophobic PCBM thin films are improved by using the treatment of a saturated bathocuproine/isopropanol (BCP/IPA) solution, which largely increases the power conversion efficiency (PCE) from 12.96% to 18.67%. The atomic force microscopic images, water-droplet contact angle images, viscosity measurement results and near-infrared transmittance spectra show that the increased open-circuit voltage (V OC ) is related to the formation of a denser PCBM thin film and the better contact quality of the PCBM/MAPbI 3 heterojunction. Besides, the power-dependent current density-voltage (J-V) curves show that the lower defect density in the solar cells results in the higher V OC . In other words, the treatment of a saturated BCP/IPA solution can decrease the defect density of the PCBM/MAPbI 3 heterojunction and thereby boosting the photovoltaic performance and extending the device lifespan. • The saturated BCP/IPA solution treatment increases the density of the PCBM thin film. • The saturated BCP/IPA solution treatment strengthens the contact quality at PCBM/MAPbI 3 interface. • The saturated BCP/IPA solution treatment increases the hydrophobicity of PCBM/MAPbI 3 heterojunction. • The saturated BCP/IPA solution treatment improves the PCE of photovoltaic cells from 12.69% to 18.67%.

Generating Synthesized Ultrasound Biomicroscopy Images from Anterior Segment Optical Coherent Tomography Images by Generative Adversarial Networks for Iridociliary Assessment.

IntroductionThe aim of this study was to investigate the feasibility of generating synthesized ultrasound biomicroscopy (UBM) images from swept-source anterior segment optical coherent tomography (SS-ASOCT) images using a cycle-consistent generative adversarial network framework (CycleGAN) for iridociliary assessment on a cohort presenting for primary angle-closure screening.MethodsThe CycleGAN architecture was adopted to synthesize high-resolution UBM images trained on the SS-ASOCT dataset from the department of ophthalmology, Xinhua Hospital. The performance of the CycleGAN model was further tested in two separate datasets using synthetic UBM images from two different ASOCT modalities (in-distribution and out-of-distribution). We compared the ability of glaucoma specialists to assess the image quality of real and synthetic images. UBM measurements, including anterior chamber, iridociliary parameters, were compared between real and synthetic UBM images. Intra-class correlation coefficients, coefficients of variation, and Bland–Altman plots were used to assess the level of agreement. The Fréchet Inception Distance (FID) was measured to evaluate the quality of the synthetic images.ResultsThe whole trained dataset included anterior chamber angle images, of which 4037 were obtained by SS-ASOCT and 2206 were obtained by UBM. The image quality of real versus synthetic SS-ASOCT images was similar as assessed by two glaucoma specialists. The Bland–Altman analysis also suggested high consistency between measurements of real and synthetic UBM images. In addition, there was fair to excellent agreement between real and synthetic UBM measurements for the in-distribution dataset (ICC range 0.48–0.97) and the out-of-distribution dataset (ICC range 0.52–0.86). The FID was 21.3 and 24.1 for the synthetic UBM images from the in-distribution and out-of-distribution datasets, respectively.ConclusionWe developed a CycleGAN model to translate UBM images from non-contact SS-ASOCT images. The CycleGAN synthetic UBM images showed fair to excellent reproducibility when compared with real UBM images. Our results suggest that the CycleGAN technique is a promising tool to evaluate the iridociliary and anterior chamber in an alternative non-contact method.

Conformal Loading Effects of P3CT-Na Polymers on the Performance of Inverted Perovskite Solar Cells

The conformal loading effects of P3CT-Na polymers on ITO/glass samples were investigated using different concentrations of P3TC-Na/water solution, which significantly influenced the device efficiency of the resultant inverted perovskite solar cells. The obtained water-droplet contact angle images, surface morphological images, photoluminescence spectra and X-ray diffraction patterns show that the hydrophilic moiety of the P3CT-Na polymers plays an important role in the conformal loading effects, thereby resulting in a smoother perovskite crystalline film due to the formation of merged grains. It is noted that the average power conversion efficiency increases from 14.83% to 17.27% with a decrease in the concentration of the P3CT-Na/water solution from 60 wt% to 48 wt%.

Spatial weighted fusion based on polarisation image

ABSTRACT This paper uses the principles of polarisation to calculate the Stokes component of the polarisation image. It designs the spatial weighted fusion algorithm, focusing on the research and evaluation of the accuracy and time complexity of the spatial weighted fusion algorithm in the polarisation image fusion processing. The spatial weighted image fusion algorithm is used to fuse the polarisation degree image, the polarisation angle image, and the light intensity image. Finally, the algorithm function is realised through software programming to verify the effect and accuracy of the algorithm. Experimental results show that the spatial weighted fusion algorithm can keep the pixel value of the polarisation source image unchanged, avoid image distortion, artefacts and ringing effects algorithm is stable and efficient, with low time complexity.

HIERARCHICAL AERIAL TRIANGULATION OF OBLIQUE IMAGE DATA

Abstract. Oblique imaging sensor systems are becoming a standard for photogrammetric applications such as city modeling, with increasing need for frequently updated geospatial data in urban areas. The ground processing software has to consider and support this develop-ment, providing a highly performant workflow for projects that can consist of tens or hundreds of thousands of images in different view angles: nadir (vertical), left, right, backward, forward. This is a challenge also for the oblique aerial triangulation (AT), both the large number of images to process and the high amount of overlap in-between them, where more than 50 image measurements for a given ground point are common.At the same time, the large overlap even in a single view generally provides stable sub-blocks for each viewing direction and, therefore, allows for separating the oblique AT by view and performing a hierarchical approach: The nadir block is triangulated first, updating the exterior orientation parameters of all nadir images and providing adjusted ground points. This nadir reference can be used to tie the oblique views’ sub-blocks in subsequent AT runs to eventually provide adjusted exterior orientations for all images, with comparable accuracy to an integrated AT – but providing a significant performance gain. The hierarchical AT is a three-step approach: 1. adjust-ment of the nadir imagery, 2. adjustment of each oblique views independently by cardinal direction (East, West, North, South) while tying it to the nadir reference, and 3. computation of combined statistics and report.The paper details our AT approach and evaluates its parameterization for different oblique data sets, comparing results and performance to a fully integrated AT.

Hadamard Aperiodic Interval Codes for Parallel-Transmission 2D and 3D Synthetic Aperture Ultrasound Imaging

We present a new set of near orthogonal codes which we call Hadamard Aperiodic Interval (HAPI) codes and demonstrate their utility for parallel multi-transmitter synthetic aperture imaging. The codes are tri-state and sparse. Locations of non-zero bits are based on marks in a sequence of aperiodic intervals, also known as a Golomb ruler. The values of non-zero bits are selected from Hadamard sequences that are mutually orthogonal. This ensures that cross-correlation sidelobe magnitudes between differing codes are bounded by unity while the autocorrelation approaches a delta function with mainlobe-to-sidelobe levels scaling with the number of non-zero bits. We use simulations to demonstrate the potential of the codes for synthetic aperture imaging. A multiplicity of transmitter elements is used to transmit codes simultaneously, with a different code for each element. Echo signals are received from a multiplicity of transducer elements in parallel. Channel data from each receiver element are cross-correlated with respective HAPI codes to estimate the transmit–receive signature associated with each transmitter–receiver pair while minimizing crosstalk. This estimate of the full transmit–receive synthetic aperture dataset is then used to form high-quality images demonstrating image quality and signal-to-noise ratio improvements over multiple flash angle imaging and synthetic aperture imaging methods for linear arrays. We also demonstrate simulated full volume synthetic aperture imaging with random sparse arrays, possible with one extended HAPI code-set transmit event.

Mathematical Estimation of Particulate Air Pollution Levels by Aerosols Tomography

Air pollution control and mitigation are important factors in wellbeing and sustainability. To this end, air pollution monitoring has a significant role. Today, air pollution monitoring is mainly done by standardized stations. The spread of those stations is sparse and their cost hinders the option of adding more. Thus, arises the need for cheaper and available means to assess air pollution. In this article, a mathematical method to solve the inverse problem of aerosols tomography is proposed. The suggested method applies filtered back-projection method on a pixel-wise blur estimation. Using the method, particles’ concentrations in a 3D space is reconstructed from photos taken from different angles. The proposed method is shown to be very effective for assessing air pollution levels by means of multi angle imaging. Specifically, estimating images’ blur as an indication for Particulate Matter (PM) ambient levels. The results of the research point towards strong correlation between image blur and pollution level in the medium and the ability to reconstruct the aerosols distribution in space.

Development of Methods for Specific Capture of Biological Targets on Aluminum Substrates: Application to Bacillus subtilis Spore Detection as a Model for Anthrax.

Many (if not most) biosensors rely on functional silane coatings as a first step toward covalent immobilization of specific capture molecules. While methods for silanization of silica (SiO2) surfaces are very well developed, less has been done to develop and characterize silanization methods for alternative substrates, such as alumina (Al2O3). In particular, the behavior of Al2O3 coatings grown on aluminum under ambient conditions has not been studied. To address this issue, we have tested solution-phase deposition of two silanes on Al2O3 (3-aminopropyl triethoxysilane and 3-triethoxysilyl)propylsuccinic anhydride) and their applicability to analyte-specific biosensing. Contact angle measurements and imaging via Scanning Electron Microsopy (SEM) were employed to characterize surfaces. We find that 3-aminopropyl triethoxysilane produces well-behaved films and demonstrate that this surface can undergo further reaction with glutaraldehyde followed by an anti-Bacillus subtilis antibody to yield functionalized Al2O3 surfaces capable of specific capture of B. subtilis spores (a model of B. anthracis, the causative organism of Anthrax). In contrast, 3-triethoxysilyl)propylsuccinic anhydride did not behave well with Al/Al2O3 under the reaction conditions tested. In addition to providing specific protocols for Al/Al2O3 functionalization, this work highlights the importance of surface chemistry assessment in the development of new sensors.

Prepare of sunlight response NH2-MIL-125/PES composites ultrafiltration membrane for flux incrementation and fouling alleviation

In this paper, a novel hydrophilic composite polyethersulfone (PES) ultrafiltration membrane was prepared by blending sunlight response photocatalyst NH2-MIL-125 via the phase inversion method. The physical-chemistry performance of membrane was carried out by XRD, FTIR, UV-VIS/DRS, contact angle, and cross-section SEM images. The separation ability, anti-fouling ability, and self-cleaning efficiency of ultrafiltration membrane were analyzed by ultrafiltration experiment using the congo red solution. The results indicate that fouling resistance and the flux recovery ratio of ultrafiltration membrane is significantly improved, and it has higher solar response energy. There was no significant change in the rejection ratio of pollutants before and after illumination. For the pristine PES membrane and the 0.5% NH2-MIL-125/PES nanocomposite membrane, the water flux recovery ratio (FRR) could increase from 37.84% to 77.09%, and the Rr could increase from 22.22% to 44.09%, and the Rir could decrease from 67.11% to 47.09%. In a conclusion, the addition of NH2-MIL-125 at a low concentration could result in membranes with more pure water flux, better rejection, and good fouling resistance compared to the unfilled PES membrane.

Planar wide-angle-imaging camera enabled by metalens array

Wide-angle imaging is an important function in photography and projection, but it also places high demands on the design of the imaging components of a camera. To eliminate the coma caused by the focusing of large-angle incident light, traditional wide-angle camera lenses are composed of complex optical components. Here, we propose a planar camera for wide-angle imaging with a silicon nitride metalens array mounted on a CMOS image sensor. By carefully designing proper phase profiles for metalenses with intentionally introduced shifted phase terms, the whole lens array is capable of capturing a scene with a large viewing angle and negligible distortion or aberrations. After a stitching process, we obtained a large viewing angle image with a range of > 120 ∘ using a compact planar camera. Our device demonstrates the advantages of metalenses in flexible phase design and compact integration, and the prospects for future imaging technology.

Wide field of view re-configurable foveal projection systems using a phase only spatial light modulator: an application to a new generation of automotive HUDs.

This paper shows how a phase only spatial light modulator (SLM) can be used to implement compact, wide field of view (FOV) projection systems, using a foveal imaging approach. The SLM is tested in two different configurations. First, as a wavefront corrector to locally compensate aberrations in wide angle projection, when illuminated by a white (RGB) light source. Second, as re-configurable diffractive optical element (DOE) to display phase computer generated holograms (CGHs) of wide angle images, that include aberration corrections for peripheral regions of interest (ROI) of the output image, when illuminated by a coherent source. Finally, the foveal projection system is coupled with a commercial combiner to project 11° ×4° virtual images at 2~m and assess the foveal correction method on different ROIs in the FOV.

Центральная серозная хориоретинопатия: навигационное лечение NAVILAS 577S

Central serous chorioretinopathy (CSC) is a common retinal disease whose etiology and pathogenesis remain largely ambiguous. Subthreshold micropulsed laser (SMILV) treatment has been intensively used for the treatment of CSC over the last decade. Purpose. To develop a method for the treatment of macular edema in CSC by subthreshold micropulse laser exposure on the Navilas 577s navigation laser system. Material and methods. The study included 65 subjects (65 eyes), 32 to 54 years of age, with acute and chronic CSC. All patients underwent standard ophthalmological examination and additional examinations including: optical coherence tomography (OCT) Topcon DRI OCT Triton and OCT-A, Maia microperimetry, autofluorescence of the eye with Zeiss Clarus 500 wide angle imaging system. Treatment was performed by SMILV using Navilas 577s system in patients with acute and chronic forms. Results. The main criteria for the effectiveness of the treatment were: an increase in maximum corrected visual acuity (BCVA), a decrease in neuroepithelial detachment (ONE) and its attachment speed, a decrease in retinal thickness and an improvement in photosensitivity (SF). Conclusion. In the treatment of CSC, preference is given to SMILV exposure, which has a physiotherapeutic effect without visible damage to the retina. The Navilas 577s navigation laser system achieves the highest precision and efficiency in retinal laser treatment, while significantly reducing procedure time and patient discomfort. Keywords: central serous chorioretopathy (CSC), subthreshold micropulse laser exposure (SML), neuroepithelial detachment, Navilas 577s.

Regioregularity effects of p-type P3CT-Na polymers on inverted perovskite photovoltaic cells

X-ray diffraction patterns, Atomic-force microscopic images, water-droplet contact angle images, absorbance spectra, photoluminescence (PL) quenching experiments and nanosecond time-resolved PL curves were used to investigate the formation of CH3NH3PbI3 (MAPbI3) crystalline thin films on top of poly[3-(4-carboxybutyl)thiophene-2,5-diyl]-Na (P3CT-Na) with the different regioregularities. The experimental results show that the higher regioregularity P3TC-Na can result in the larger MAPbI3 grains along the (110) direction of tetragonal perovskite and thereby increasing the averaged power conversion efficiency (PCE) of the resultant perovskite photovoltaic cells from 14.13% to 16.81% mainly due to the reduced potential loss in the MAPbI3 crystalline thin film. Besides, a remarkable fill factor of 80.9% was achieved, which can be used to explain the stable photovoltaic performance of the encapsulated cells.

Smartphone Gonioscopy With a Magnifying Intraocular Lens: A Cost-effective Angle Imaging Device.

Gonioscopy is an important part of glaucoma diagnosis and management. Imaging and documentation of the anterior chamber angle has been previously performed using slit-lamp-assisted photography or using smartphones with or without an attached macro lens. Smartphones have transformed ophthalmic imaging by virtue of their availability, easy use, and portability. In this report, the authors aim to demonstrate gonio-imaging using a smartphone attached with an intraocular lens which behaves like a macro lens. With the patient in a sitting position or in the supine position, a goniolens is placed on the patient's cornea. A smartphone with a 10 D intraocular lens attachment over its camera is used to take images or videos of the anterior chamber angle with high magnification. This imaging modality is cost-effective and can be used for screening and photographic documentation of the angle, and can be of immense benefit, especially in primary health care centers.

Feature Classification-Based Inclination Measurement for Industrial Assembly Platform

This paper proposed a method to realize inclination measurement for the industrial Internet of Things (IIoT) assembly platform by utilizing deep learning technology. Because the existence of inclination angle of platform will introduce slight damages to the products during the assembly process, our research group designed a system to tackle this problem by replacing the motion estimation algorithm with a classification mechanism. In other words, by classifying the image of the installation platform, it is capable to determine which inclination angle (image class) an input image belongs to. From the analysis of evaluation experiments, the proposed system for inclination measurement mechanism is proved effective when tackling the problems mentioned above. In addition, the proposed IoT system costs less computation power and achieves relatively higher measurement accuracy.

Evaluation of Cardiac Space-Occupying Lesions by Myocardial Contrast Echocardiography and Transesophageal Echocardiography.

Heart space-occupying lesions are a disease that occurs frequently in clinical setting, and therefore, it is important to diagnose and treat this type of pathologies properly. Angiographic echocardiography and transesophageal sonogram are widely used for clinical diagnosis. Their application provides a guarantee for the diagnosis of cardiac space-occupying lesions. In this paper, the application of cardiac contrast echocardiography and transesophageal echocardiography in cardiac space-occupying lesions was studied. Prediction of cardiac lesions can accurately determine the nature of cardiac occupancies and provide a basis for clinical diagnosis and management judgments. The results of pathological analysis and experimental comparison showed that myocardial contrast echocardiography can accurately distinguish tumor and thrombus and make contribution to patients taking appropriate medical measures. At the same time, it can compare conventional transthoracic echocardiography and transesophageal echocardiography. The results showed that TEE could clearly show the cardiac lesions. The experimental data of 76.9% confirmed cases showed that the diagnostic accuracy is greatly improved. TEE can also clearly show small thrombus that TTE cannot, in which 2DTEE can clearly show the boundary between the space-occupying and surrounding tissues, and whether there is a clear boundary between the space-occupying and surrounding tissues is an important distinguishing point of benign and malignant tumors. In addition, the TEE probe can also be used for large angle imaging and multiangle rotation, so as to determine the tumor boundary and the spatial position relationship between the tumor and the surrounding tissue. All in all, myocardial contrast echocardiography and transesophageal echocardiography have better clinical application effect on cardiac space-occupying lesions.