Full Frame Research Articles

On the possibility to utilize a PCO Edge 4.2 bi scientific CMOS imager for extended ultra violet and soft X-ray photon detection

A state of the art commercial detector, a PCO Edge 4.2 bi based on a back illuminated sCMOS sensor developed for applications in the visible light/ultra violet regime has been adapted for ultra-high vacuum operations and has been characterized using soft X-ray in the energy range from 30 eV to 1000 eV. The imager features 2048 × 2048 pixel with a pixel size of 6.5 μm × 6.5 μm and allows full frame acquisitions at 48 Hz with a dynamic range of 88 dB at a noise level of 1.9 e −. Spatial resolution and quantum efficiency have been elucidated in the aforementioned energy range at a soft X-ray beam line at Elettra Sincrotrone Trieste. The handiness of the camera as well as its Python library package allows easy and fast integration into the beam line environments of synchrotron sources and free electron lasers.

A Pair of Warm Giant Planets near the 2:1 Mean Motion Resonance around the K-dwarf Star TOI-2202*

Abstract TOI-2202 b is a transiting warm Jovian-mass planet with an orbital period of P = 11.91 days identified from the Full Frame Images data of five different sectors of the TESS mission. Ten TESS transits of TOI-2202 b combined with three follow-up light curves obtained with the CHAT robotic telescope show strong transit timing variations (TTVs) with an amplitude of about 1.2 hr. Radial velocity follow-up with FEROS, HARPS, and PFS confirms the planetary nature of the transiting candidate (a b = 0.096 ± 0.001 au, m b = 0.98 ± 0.06 M Jup), and a dynamical analysis of RVs, transit data, and TTVs points to an outer Saturn-mass companion (a c = 0.155 ± 0.002 au, m c = 0.37 ± 0.10 M Jup) near the 2:1 mean motion resonance. Our stellar modeling indicates that TOI-2202 is an early K-type star with a mass of 0.82 M ⊙, a radius of 0.79 R ⊙, and solar-like metallicity. The TOI-2202 system is very interesting because of the two warm Jovian-mass planets near the 2:1 mean motion resonance, which is a rare configuration, and their formation and dynamical evolution are still not well understood.

A time-division correction method for adaptive optics system

An adaptive optics system can measure and compensate the wavefront distortion caused by dynamic disturbance in real time. It is usually used for astronomical observation and other occasions. According to the current technology, it is only suitable for small field of view optical system or point target, but not for ground extended target detection. In order to solve this problem, a correction method is proposed: firstly, the sub aperture image of wavefront sensor is divided into several sub regions, each sub region corresponds to a certain light direction or field angle range; secondly, calculate the offset of the image feature points in each sub region, and an image with good correction effect in a field of view in this direction is obtained; the last step is to measure each sub region one by one and combine these images into a full frame image. Through comparison, it is found that the method proposed in this paper is essentially to divide the extended target into multiple point light sources for correction.

Progressive collapse mechanisms of post-tensioned reinforced concrete frames considering effect of infill walls

This study numerically investigates progressive collapse mechanisms of post-tensioned RC frames under column removal scenarios by using the finite element method. The primary objective of this study is to investigate the influences of infill walls on mechanical behavior of post-tensioned (PT) frames against progressive collapse. Three experimental conventional reinforced concrete (RC) frames are modified into PT reinforced concrete frames: PT bare frame, PT full infilled frame and PT partial infilled frame. The numerical study was performed and the applied vertical load, horizontal displacement, failure process, load redistribution mechanisms, and re-centering capacity of PT frames are investigated under middle column pushdown scenario. Parametric analyses are conducted to study influences of material properties, arrangement of PT tendons, and magnitude of PT forces. The results show that masonry infill walls enhance the resisting capacity; however, change the failure modes and reduce the re-centering capacity of the PT frames against progressive collapse. The presence of the opening reduces the contribution of the infill walls. The PT bare frame have better resilience performance compared with the conventional bare frame. The bed joints, strength of masonry bricks, arrangement of PT tendons and magnitude of PT force greatly influence the progressive collapse resisting capacity of PT frames. Finally, a preliminary design method is proposed to predict the progressive collapse resisting capacity of PT frames with good accuracy and efficiency.

Morphometric Analysis through 3D Modelling of Bronze Age Stone Moulds from Central Sardinia

Stone moulds were basic elements of metallurgy during the Bronze Age, and their analysis and characterization are very important to improve the knowledge on these artefacts useful for typological characterization. The stone moulds investigated in this study were found during an archaeological field survey in several Nuragic (Bronze Age) settlements in Central Sardinia. Recent studies have shown that photogrammetry can be effectively used for the 3D reconstruction of small and medium-sized archaeological finds, although there are still many challenges in producing high-quality digital replicas of ancient artefacts due to their surface complexity and consistency. In this paper, we propose a multidisciplinary approach using mineralogical (X-ray powder diffraction) and petrographic (thin section) analysis of stone materials, as well as an experimental photogrammetric method for 3D reconstruction from multi-view images performed with recent software based on the CMPMVS algorithm. The photogrammetric image dataset was carried out using an experimental rig equipped with a 26.2 Mpix full frame digital camera. We also assessed the accuracy of the reconstruction models in order to verify their precision and readability according to archaeological goals. This allowed us to provide an effective tool for more detailed study of the geometric-dimensional aspects of the moulds. Furthermore, this paper demonstrates the potentialities of an integrated minero-petrographic and photogrammetric approach for the characterization of small artefacts, providing an effective tool for more in-depth investigation of future typological comparisons and provenance studies.

Data-Driven Convolutional Model for Digital Color Image Demosaicing

Modern digital cameras use specific arrangement of Color Filter Array to sample light wavelength corresponding to visible colors. The most common Color Filter Array is the Bayer filter that samples only one color per pixel. To recover the full resolution image, an interpolation algorithm can be used. This process is called demosaicing and it is one of the first processing stages of a digital imaging pipeline. We introduce a novel data-driven model for demosaicing that takes into account the different requirements for reconstruction of the image Luma and Chrominance channels. The final model is a parallel composition of two reconstruction networks with individual architecture and trained with distinct loss functions. In order to solve the overfitting problem, we prepared a dataset that contains groups of patches that share common chromatic and spectral characteristics. We reported the reconstruction error on noise-free images and measured the effect of random noise and quantization noise in the demosaicing reconstruction. To test our model performance, we implemented the network on NVIDIA Jetson Nano, obtaining an end-to-end running time of less than one second for a full frame 12 MPixel image.

Basis expansion model for tracking and equalizing rapidly varying multimode fiber channels

In multi-mode fibers, environmental perturbations induce changes in the channel transfer matrix at rates proportional to the total length of affected segments and the number of modes; potentially reaching levels where adaptive equalizers fail in tracking the channel state. We propose a technique that tracks the channel on a frame-by-frame basis by modeling variations in mode coupling coefficients over the period of a full frame of symbols as a linear combination of discrete prolate spheroidal sequences (DPSS). In simulations of rapidly varying channel scenarios where least-mean square (LMS) and recursive least squares (RLS) fail completely, our proposed approach consistently tracks and equalizes the channel variation; yielding a symbol error rate of 10-4 at 15-dB signal-to-noise ratio. DPSS, being matched to the dynamic channel behaviour, is a key factor in minimizing the pilot resources expended in channel estimation, with losses in spectral efficiency starting from 4% up to 20% in the worst case.

Accelerating multi-emitter localization in super-resolution localization microscopy with FPGA-GPU cooperative computation.

The real-time multi-emitter localization method is essential for advancing high-throughput super-resolution localization microscopy (HT-SRLM). In the past decade, the graphics processing unit (GPU) computation has been dominantly used to accelerate the execution speed of the multi-emitter localization method. However, if HT-SRLM is combined with a scientific complementary metal-oxide-semiconductor (sCMOS) camera working at full frame rate, real-time image processing is still difficult to achieve using this acceleration approach, thus resulting in a massive data storage challenge and even system crash. Here we take advantage of the cooperative acceleration power of field programming gate array (FPGA) computation and GPU computation, and propose a method called HCP-STORM to enable real-time multi-emitter localization. Using simulated images, we verified that HCP-STORM is capable of providing real-time image processing for raw images from a representative Hamamatsu Flash 4 V3 sCMOS camera working at full frame rate (that is, 2048×2048 pixels @ 10 ms exposure time). Using experimental images, we prove that HCP-STORM is 25 times faster than QC-STORM and 295 times faster than ThunderSTORM, with a small but acceptable degradation in image quality. This study shows the potential of FPGA-GPU cooperative computation in accelerating multi-emitter localization, and pushes a significant step toward the maturity of HT-SRLM technology.

TIC 257060897b: An inflated, low-density, hot-Jupiter transiting a rapidly evolving subgiant star

ABSTRACT We report the discovery of a new transiting exoplanet orbiting the star TIC 257060897 and detected using TESS full frame images. We acquired HARPS-N time-series spectroscopic data, and ground-based photometric follow-up observations from which we confirm the planetary nature of the transiting body. For the host star we determined: Teff = (6128 ± 57) K, log g = (4.2 ± 0.1), and [Fe/H] = (+ 0.20 ± 0.04). The host is an intermediate age (∼3.5 Gyr), metal-rich, subgiant star with M⋆ = (1.32 ± 0.04) M⊙ and R⋆ = (1.82 ± 0.05) R⊙. The transiting body is a giant planet with a mass mp =(0.67 ± 0.03) Mj, a radius rp = (1.49 ± 0.04) Rj yielding a density ρp = (0.25 ± 0.02) g cm−3 and revolving around its star every ∼3.66 d. TIC 257060897b is an extreme system having one of the smallest densities known so far. We argued that the inflation of the planet’s radius may be related to the fast increase of luminosity of its host star as it evolves outside the main sequence and that systems like TIC 257060897b could be precursors of inflated radius short period planets found around low luminosity red giant branch stars, as recently debated in the literature.

Wide angle holographic video projection display.

Holographic projection displays provide high diffraction efficiency. However, they have a limited projection angle. This work proposes a holographic projection display with a wide angle, which gives an image of size 306mm×161mm at 700 mm and reduced speckle noise. The solution uses single Fourier lens imaging with a frequency filter and hologram generation utilizing complex coding and nonparaxial diffraction. The experiment was performed with a 4K phase-only spatial light modulator (SLM) to prove the high efficiency of the developed numerical tools. Optical reconstruction shows high resolution and high image quality achieved from a single frame. Hence, displaying video at a full frame rate of the SLM is possible.

TESS Data for Asteroseismology: Photometry

Abstract Over the last two decades, asteroseismology has increasingly proven to be the observational tool of choice for the study of stellar physics, aided by the high quality of data available from space-based missions such as CoRoT, Kepler, K2, and the Transiting Exoplanet Survey Satellite (TESS). TESS in particular will produce more than an order of magnitude more such data than has ever been available before. While the standard TESS mission products include light curves from 120 s observations suitable for both exoplanet and asteroseismic studies, they do not include light curves for the vastly larger number of targets observed by the mission at a longer 1800 s cadence in Full Frame Images (FFIs). To address this lack, the TESS Data for Asteroseismology (T’DA) group under the TESS Asteroseismic Science Consortium (TASC) has constructed an open-source pipeline focused on producing light curves for all stars observed by TESS at all cadences, currently including stars down to a TESS magnitude of 15. The pipeline includes target identification, background estimation and removal, correction of FFI time stamps, and a range of potential photometric extraction methodologies, though aperture photometry is currently the default approach. For the brightest targets, we transparently apply a halo photometry algorithm to construct a calibrated light curve from unsaturated pixels in the image. In this paper, we describe in detail the algorithms, functionality, and products of this pipeline and summarize the noise metrics for the light curves. Companion papers will address the removal of systematic noise sources from our light curves, and a stellar variability classification from these.

Fire performance of earthquake-damaged reinforced concrete columns: an experimental study

PurposeEarthquake tremors not only increase the chances of fire ignition but also hinder the fire-fighting efforts due to the damage to the lifelines of a city. Most of the international codes have independent recommendations for structural safety against earthquake and fire. However, the possibility of a multi-hazard event, such as fire following an earthquake is seldom addressed.Design/methodology/approachThis paper presents an experimental study of Reinforced Concrete (RC) columns in post-earthquake fire (PEF) conditions. An experimental approach is proposed that allows the testing of a column instead of a full structural frame. This approach allows us to control the loading and boundary conditions individually and facilitates the testing under a variety of these conditions. Also, it allows the structure to be tested until failure. The role of parameters, such as earthquake intensity, axial load ratio and the ductile detailing of the column on the earthquake damage and subsequently the fire performance of the structure, is studied in this research. Six RC column specimens are tested under a sequence of quasi-static earthquake loading, followed by combined fire and axial compression loading conditions.FindingsThe experiment results indicate that ductile detailed columns subjected to 4% or less lateral drift did not lose significant load-carrying capacity in fire conditions. A lateral drift of 6% caused significant damage to the columns and reduced the load-carrying capacity in fire conditions. The level of the axial load acting on the column at the time of earthquake loading was found to have a very significant effect on the extent of damage and reduction in column load capacity in fire conditions. The columns that were not detailed for a ductile behavior observed a more significant reduction in axial load carrying capacity in fire conditions.Research limitations/implicationsThis study is limited to columns of 230 mm size due to the limitations of the test setup. The applicability of these findings to larger column sections needs to be verified by developing a numerical analysis methodology and simulating other post-earthquake-fire tests available in the literature.Originality/valueThe experimental procedure proposed in this paper offers an alternative to the testing of a complete structural frame system for PEF behavior. In addition to the ease of conducting the tests, the procedure also allows much better control over the heating, structural loading and boundary conditions.

Incremental inelastic dynamic damage analysis of MRRCFs infilled with masonry panels

Calculus complexity, time-consuming and high computational effort of the nonlinear dynamic analysis coupled with the complexity of simulating the interaction between masonry infill walls and reinforced concrete frames cause this fact that infill panels are usually considered as the non-structural elements to analyze and design the process of reinforced concrete frames infilled with masonry walls. In this study, to predict the influence of masonry infill panels on the imposed damage of moment-resisting reinforced concrete frames (MRRCFs) under earthquake excitation, incremental inelastic dynamic damage analyses are performed several MRRCFs under twenty seismic ground motions. The MRRCFs are simulated once without considering masonry infill wall effect (as bare frames) and another one considering masonry infill wall effect (as infilled frames). The diagonal compression strut model used to simulate the infill walls is compared with some other proposals in terms of the equivalent strut width, the bed-joint sliding shear strength, the diagonal tension cracking strength, the corner crushing strength, and the diagonal compression strength. Results show that the equivalent strut width, the diagonal tension cracking strength, and the corner crushing strength predicted by FEMA306 are in reasonable compliance with the model used in this study. The capacity and damage curves of bare, and partial, and full infilled frames using incremental dynamic analyses are achieved and compared. The consequences proved that masonry infill walls improve the lateral load-bearing capacity of MRRCFs and decrease the imposed damage of these frames in the seismic excitations. Furthermore, two relations are derived to predict the damage of bare and infilled frames under the earthquake excitations. To assess the accuracy of proposed relations, three new frames are designed. The values of their seismic damage are achieved through inelastic damage analyses and presented relations. Comparing the outcomes confirms the validity of proposed relations.

A look at the structure of congruence frames by means of Heyting congruences

This paper concerns the congruence frame in the setting of partial frames, which, in contrast to full frames, do not necessarily have all joins. Examples of these include bounded distributive lattices, σ- and κ-frames. A new class of congruences, called Heyting congruences, helps to illuminate the structure of these congruence frames. Defining these involves the very useful free frame over a partial frame. We investigate the relationship between Heyting congruences and co-atoms of the congruence frame, showing how different the cases of full and partial frames can be. The Madden congruence, which yields the least dense quotient, is recognized as a particular Heyting congruence. While the collection of all Heyting congruences on a partial frame is in general not even a meet-semilattice, joining each of them with the Madden congruence results in a collection with considerably more interesting structure.

Characterization and mitigation of electronic crosstalk on InGaAs PIN 3D flash LiDAR imagers

This research presents methods and results of characterizing and mitigating electronic crosstalk on InGaAs PIN photodiode 3D flash LiDAR imagers, with the goal of significantly simplifying and improving the calibration system design. 3D flash LiDAR detectors use time to digital conversion (TDC) circuits to estimate the time of flight of a pulse when a detection threshold is met. As the underlying TDC circuits require more space and power, these circuits will cause, in high bus loading events, electronic crosstalk. These events are more likely to occur in situations where many detectors simultaneously trigger, something that can occur when viewing a flat object head-on with uniform illumination, thus limiting these sensors to image a full frame due to this simultaneous ranging crosstalk noise (SRCN). Solutions previously devised to mitigate this electronic crosstalk included using a windowed region of interest to mitigate additional noise by preventing triggering on all of the focal plane array (FPA) except the windowed region and using a checkerboard pattern for imaging the full frame. Here the electronic crosstalk is characterized, and mitigated, using a physical checkerboard target, leading to a more compact system design using a spatial light modulator and direct illumination.

The residence of synaptically released dopamine on D2 autoreceptors.

SUMMARYNeuromodulation mediated by synaptically released endogenous transmitters acting in G-protein-coupled receptors (GPCRs) is slow primarily because of multistep downstream signaling. What is less well understood is the spatial and temporal kinetics of transmitter and receptor interaction. The present work uses the combination of the dopamine sensor, dLight, to detect the spatial release and diffusion of dopamine and a caged form of a D2-dopamine receptor antagonist, CyHQ-sulpiride, to rapidly block the D2 autoreceptors. Photoactivation of the CyHQ-sulpiride blocks receptors in milliseconds such that the time course of dopamine/receptor interaction is mapped onto the downstream signaling. The results show that highly localized release, but not dopamine diffusion, defines the time course of the functional interaction between dopamine and D2 autoreceptors, which determines downstream inhibition.

A characteristic map for the holonomy groupoid of a foliation

We prove a generalisation of Bott’s vanishing theorem for the full transverse frame holonomy groupoid of any transversely orientable foliated manifold. As a consequence we obtain a characteristic map encoding both primary and secondary characteristic classes. Previous descriptions of this characteristic map are formulated for the Morita equivalent étale groupoid obtained via a choice of complete transversal. By working with the full holonomy groupoid we obtain novel geometric representatives of characteristic classes. In particular we give a geometric, non-étale analogue of the codimension 1 Godbillon–Vey cyclic cocycle of Connes and Moscovici in terms of line integrals of the curvature form of a Bott connection.

The Changing Lightcurve of the Double-mode RR Lyrae Variable Star V338 Boo

Abstract We present an analysis of the lightcurve extracted from Transiting Exoplanet Survey Satellite (TESS) Full Frame Images (FFIs) of the double-mode RR Lyrae V338 Boo. We find that the fundamental mode pulsation is changing in amplitude across the 54 days of observations. The first overtone mode pulsation also changes, but on a much smaller scale. Harmonics and combinations of the primary pulsation modes also exhibit unusual behavior. Possible connections with other changes in RR Lyrae pulsations are discussed, but a full understanding of the cause of the changes seen in V338 Boo should shed light on some of the most difficult and unanswered questions in stellar pulsation theory, and astrophysics more generally.

The Weizmann Fast Astronomical Survey Telescope (W-FAST): System Overview

A relatively unexplored phase space of transients and stellar variability is that of second and sub-second timescales. We describe a new optical observatory operating in the Negev desert in Israel, with a 55 cm aperture, a field of view of 2.°6 × 2.°6 (≈7 deg2) equipped with a high frame rate, low read noise, CMOS camera. The system can observe at a frame rate of up to 90 HZ (full frame), while nominally observations are conducted at 10–25 Hz. The data, generated at a rate of over 6 Gbits s−1 at a frame rate of 25 Hz, are analyzed in real time. The observatory is fully robotic and capable of autonomously collecting data on a few thousand stars in each field each night. We present the system overview, performance metrics, science objectives, and some first results, e.g., the detection of a high rate of glints from geosynchronous satellites, reported in Nir et al. 2020.

TESS as a Low-surface-brightness Observatory: Cutouts from Wide-area Coadded Images

Abstract We present a mosaic of those co-added Full Frame Images acquired by the TESS satellite that had been released in 2020 April. The mosaic shows substantial stray light over the sky. Yet over spatial scales of a few degrees, the background appears uniform. This result indicates that TESS has considerable potential as a Low Surface Brightness Observatory. The co-added images are freely available as a High Level Science Product (HLSP) at MAST and accessible through a Jupyter Notebook.