High-resolution Imaging System Research Articles

High-Resolution Intelligent Imaging System with Wide Field of View Based on Eagle Eye

High-Resolution Intelligent Imaging System with Wide Field of View Based on Eagle Eye

A Magnetic Field Imaging System Based on TMR Sensors for Banknote Recognition

The high sensitivity and MEMS-compatible process of tunneling magnetoresistance (TMR) sensors provide great opportunities to develop high-resolution magnetic field detection and imaging systems. In this work, we designed a magnetic field imaging (MFI) system based on TMR sensors to detect the uniaxial magnetic field components of banknotes including US dollars (USD) and Chinese Yuan (CNY), which clearly reveals the distribution of magnetic anti-counterfeiting markers inside the banknotes. Measurement results of the USD show that the magnetic ink signal is around μT level, and the person portraits on banknotes can be revealed by the sensor signals. The testing results of the CNY banknotes indicate magnetic color-shifting ink images, as well as a clear magnetic anti-counterfeiting thread. Different from the traditional optical detection, magnetic detection provides unique signals and identification methods. With a satisfactory recognition rate, the proposed MFI system based on TMR sensors demonstrates its promising potential forgery detection and denomination identification of banknotes.

Research on terahertz real-time near-field spectral imaging

In this paper, a real-time near-field high-resolution THz (terahertz, THz) spectral imaging system is designed and built by using optical rectification and wave-front tilting to generate strong-field terahertz signals and based on electro-optical detection. The system can switch between large beam THz imaging and tight-focusing THz imaging, which provides a method for implementing the integrated application of the system. Since the imaging is based on the traditional THz time-domain spectroscopy method, the spectral amplitude and phase information of the sample can be obtained simultaneously. The spectral resolution is about 15 GHz. A series of micromachining samples is measured and studied by using the system, and the performance of the imaging system is analyzed by using the micron structure. The results show the superiority of the real-time high-resolution terahertz spectral imaging system in terms of spatial resolution and imaging speed. The real-time imaging frame rate is up to 20 f/s (1200 frames/min) at 1024 pixel × 512 pixel. In the large-field THz imaging, the optimal spatial resolution reaches <i>λ</i>/4 at 1.5 THz. In the tightly focused THz imaging, the optimal spatial resolution reaches λ/12 at 0.82 THz. These properties make the system suitable for the applications in biomedical imaging, bbological effects and other areas .

Design and Test of High-Resolution Imaging System for Ultracold Atoms

Design and Test of High-Resolution Imaging System for Ultracold Atoms

Intensity-based nonrigid endomicroscopic image mosaicking incorporating texture relevance for compensation of tissue deformation

Image mosaicking has emerged as a universal technique to broaden the field-of-view of the probe-based confocal laser endomicroscopy (pCLE) imaging system. However, due to the influence of probe-tissue contact forces and optical components on imaging quality, existing mosaicking methods remain insufficient to deal with practical challenges. In this paper, we present the texture encoded sum of conditional variance (TESCV) as a novel similarity metric, and effectively incorporate it into a sequential mosaicking scheme to simultaneously correct rigid probe shift and nonrigid tissue deformation. TESCV combines both intensity dependency and texture relevance to quantify the differences between pCLE image frames, where a discriminative binary descriptor named fully cross-detected local derivative pattern (FCLDP) is designed to extract more detailed structural textures. Furthermore, we also analytically derive the closed-form gradient of TESCV with respect to the transformation variables. Experiments on the circular dataset highlighted the advantage of the TESCV metric in improving mosaicking performance compared with the other four recently published metrics. The comparison with the other four state-of-the-art mosaicking methods on the spiral and manual datasets indicated that the proposed TESCV-based method not only worked stably at different contact forces, but was also suitable for both low- and high-resolution imaging systems. With more accurate and delicate mosaics, the proposed method holds promises to meet clinical demands for intraoperative optical biopsy.

Production of a Three-Dimensional Triangulated Irregular Network (3D TIN) for Al-Karkh University of Science, Baghdad- Iraq

Many satellite systems take cover images like QuickBird for terrain so that these images scan be used to construct 3D models likes Triangulated Irregular Network (TIN), and Digital Elevation Model (DEM). This paper presents a production of 3D TIN for Al-Karkh University of Science in Baghdad - Iraq using QuickBird image data with pixel resolution of 0.6 m. The recent generations of high-resolution satellite imaging systems open a new era of digital mapping and earth observation. It provides not only multi-spectral and high-resolution data but also the capability for stereo mapping. The result of this study is a production of 3D satellite images of the university by merging 1 m DEM with satellite image for ROI using ArcGIS package Version 10.3.

A Microphysiological Cell-Culturing System for Pharmacokinetic Drug Exposure and High-Resolution Imaging of Arrays of 3D Microtissues.

Understanding the pharmacokinetic/pharmacodynamic (PK/PD)-relationship of a drug candidate is key to determine effective, yet safe treatment regimens for patients. However, current testing strategies are inefficient in characterizing in vivo responses to fluctuating drug concentrations during multi-day treatment cycles. Methods based on animal models are resource-intensive and require time, while traditional in vitro cell-culturing methods usually do not provide temporally-resolved information on the effects of in vivo–like drug exposure scenarios. To address this issue, we developed a microfluidic system to 1) culture arrays of three-dimensional spheroids in vitro, to 2) apply specific dynamic drug exposure profiles, and to 3) in-situ analyze spheroid growth and the invoked drug effects in 3D by means of 2-photon microscopy at tissue and single-cell level. Spheroids of fluorescently-labeled T-47D breast cancer cells were monitored under perfusion-culture conditions at short time intervals over three days and exposed to either three 24 h-PK-cycles or a dose-matched constant concentration of the phosphatidylinositol 3-kinase inhibitor BYL719. While the overall efficacy of the two treatment regimens was similar, spheroids exposed to the PK profile displayed cycle-dependent oscillations between regression and regrowth. Spheroids treated with a constant BYL719 concentration regressed at a steady, albeit slower rate. At a single-cell level, the cell density in BYL719-treated spheroids oscillated in a concentration-dependent manner. Our system represents a versatile tool for in-depth preclinical characterization of PK/PD parameters, as it enables an evaluation of drug efficacy and/or toxicity under realistic exposure conditions.

A review of terahertz phase modulation from free space to guided wave integrated devices.

In the past ten years, terahertz technology has developed rapidly in wireless communications, spectroscopy, and imaging. Various functional devices have been developed, such as filters, absorbers, polarizers, mixers, and modulators. Among these, the terahertz phase modulation is a current research hotspot. It is the core technology to realize flexible control of the terahertz wavefront, beam scanning, focusing deflection. It is indispensable in terahertz wireless communication, high-resolution imaging, and radar systems. This review summarizes the research progress of terahertz phase modulators from the two major types: free space and guided wave integration. Among these, the free space terahertz phase modulator is realized by combining the tunable materials and artificial metasurfaces. Based on different types of tunable materials, theterahertz free space phase modulator combining the semiconductor, liquid crystal, phase change materials, graphene, and other two-dimensional materials are introduced, and the influence of different materials on the phase modulation performance is discussed andanalyzed. The monolithic integration and waveguide embedding methods are introduced separately, and the characteristics of different forms of terahertz-guided wave phase modulation are also discussed. Finally, the development trends of terahertz phase modulators, possible new methods, and future application requirements are discussed.

Design and Manufacture of Traveling-wave Electro-optic Modulator for X-band LFM Signal Generation

In this paper, a photonic-based microwave system technology is described, and a traveling-wave electro-optic modulator is designed and manufactured as a key component. The fabricated modulator is composed of a metal diffusion waveguide for optical transmission and a planar waveguide electrode on lithium niobate substrate for microwave transmission. The electro-optic response bandwidth of I and Q channels in a fabricated dual parallel Mach-Zehnder modulator were measured for 27.67 and 28.11 GHz, respectively. Photonic four times up-converted X-band frequency and linear frequency modulated signal were confirmed using the fabricated electro-optic modulator by S-band input signal. The confirmed broadband signal can be applied to a microwave system for surveillance and high-resolution ISAR imaging.

A Transparent Nano-Polycrystalline ZnWO4 Thin-Film Scintillator for High-Resolution X-ray Imaging.

Facile approaches for creating thin-film scintillators with high spatial resolutions and variable shapes are required to broaden the applicability of high-resolution X-ray imaging. In this study, a transparent nano-polycrystalline ZnWO4 thin-film scintillator was fabricated by thermal evaporation for high-resolution X-ray imaging. The scintillator is composed of nano-sized grains smaller than the optical wavelength range to minimize optical scattering. The high transparency of the scintillators affords a sufficiently high spatial resolution to resolve the 2 μm line and space patterns when used in a high-resolution X-ray imaging system with an effective pixel size of 650 nm. The thermal evaporation method is a convenient approach for depositing thin and uniform films on complex substrates. ZnWO4 thin-film scintillators with various shapes, such as pixelated and curved, were fabricated via thermal evaporation. The results show that the transparent nano-polycrystalline ZnWO4 thin-film scintillator deposited through thermal evaporation has a potential for use in various high-resolution X-ray imaging applications.

Painting CROSS TCA technique: Modification of the CROSS method for the treatment of atrophic acne scars-Case series.

The Chemical Reconstruction of Skin Scars (CROSS) technique was first described in 2002 and has since demonstrated safety and efficacy in multiple studies. We describe the treatment of six patients with a modified version of the CROSS method-the Painting CROSS trichloroacetic acid (TCA) technique. This technique has the advantage of offering even higher tissue selectivity and better control of the scar edges, enhancing both safety and efficacy. We retrospectively evaluated 31scars of six patients who underwent a single treatment by the Painting CROSS TCA method. A 0.3ml insulin syringe with a 30-gauge needle was filled with 0.05ml of 85% TCA solution and then applied to the scar base with slight pressure until frosting was achieved. Patients were evaluated before and 3months after treatment for scar volume deficit by a high-resolution three-dimensional imaging system. The average volume of the 31scars assessed in our study was 2.71mm3 before treatment and 1.96mm3 after treatment. There was a 26.3% average decrease in the volume of the scars after one treatment. Transient mild hyperpigmentation was noted in two patients after the treatment. Painting CROSS TCA technique has demonstrated efficacy in the treatment of acne scars after a single treatment.

High-resolution dynamic imaging system based on a 2D optical phased array.

We propose an imaging system with scanning feedback of an optical phased array (OPA) for moving targets with unknown speed. The system combines OPA scanning velocimetry capability with OPA-based ghost imaging to enable trajectory tracking of targets moving within the field-of-view of the system while accomplishing image reconstruction. The proposed system can perform image reconstruction for millimeter-scale moving targets placed up to 20 m away from the camera. The system can be applied in areas such as autonomous driving and high-resolution imaging.

Initial experience with AcQMap catheter for treatment of persistent atrial fibrillation and atypical atrial flutter.

IntroductionThe AcQMap High Resolution Imaging and Mapping System was recently introduced. This system provides 3D maps of electrical activation across an ultrasound-acquired atrial surface.MethodsWe evaluated the feasibility and the acute and short-term efficacy and safety of this novel system for ablation of persistent atrial fibrillation (AF) and atypical atrial flutter.ResultsA total of 21 consecutive patients (age (mean ± standard deviation) 62 ± 8 years, 23% female) underwent catheter ablation with the use of the AcQMap System. Fourteen patients (67%) were treated for persistent AF and 7 patients (33%) for atypical atrial flutter. Eighteen patients (86%) had undergone at least one prior ablation procedure. Acute success, defined as sinus rhythm without the ability to provoke the clinical arrhythmia, was achieved in 17 patients (81%). At 12 months, 4 patients treated for persistent AF (29%) and 4 patients treated for atypical flutter (57%) remained in sinus rhythm. Complications included hemiparesis, for which intra-arterial thrombolysis was given with subsequent good clinical outcome (n = 1), and complete atrioventricular block, for which a permanent pacemaker was implanted (n = 2). No major complications attributable to the mapping system occurred.ConclusionThe AcQMap System is able to provide fast, high-resolution activation maps of persistent AF and atypical atrial flutter. Despite a high acute success rate, the recurrence rate of persistent AF was relatively high. This may be due to the selection of the patients with therapy-resistant arrhythmias and limited experience in the optimal use of this mapping system that is still under development.Supplementary InformationThe online version of this article (10.1007/s12471-021-01636-w) contains supplementary material, which is available to authorized users.

X-ray grating interferometry design for the 4D GRAPH-X system

The 4D GRAPH-X (Dynamic GRAting-based PHase contrast x-ray imaging) project aims at developing a prototype of an x-ray grating-based phase-contrast imaging scanner in a laboratory setting, which is based on the Moirè single-shot acquisition method in order to be optimized for analysing moving objects (in the specific case, a dynamic thorax phantom), that could evolve into a suitable tool for biomedical applications although it can be extended to other application fields. When designing an x-ray Talbot-Lau interferometer, high visibility and sensitivity are two important figures of merit, strictly related to the performance of the system in obtaining high quality phase contrast and dark-field images. Wave field simulations are performed to optimize the setup specifications and construct a high-resolution and high-sensitivity imaging system. In this work, the design of a dynamic imaging setup using a conventional milli-focus x-ray source is presented. Optimization by wave front simulations leads to a symmetric configuration with 5.25 μm pitch at third Talbot order and 45 keV design energy. The simulated visibility is about 22%. Results from GATE based Monte Carlo simulations show a 19% transmission percentage of the incoming beam into the detector after passing through all the gratings and the sample. Such results are promising in view of building a system optimized for dynamic imaging.

Acousto-optical metasurfaces for high-resolution acoustic imaging systems

This work introduces a paradigm for acoustic imaging in which a metasurface converts the acoustic waves scattered by remote scenes into coherent light focused into images by conventional optical cameras. The metasurface is composed of acousto-optical unit cells that sense the local acoustic pressure and use the resulting signal to modulate the amplitude of the electric field produced by a laser on an optical aperture. We derive the general design requirements for the image reconstruction in the optical domain and validate the concept through acoustic field measurements of the ultrasound scattered from an object submerged in water followed by numerical simulations predicting how this field is processed by the metasurface and camera. We show that this approach has two main advantages compared to traditional acoustic imaging systems. First, the acoustic-to-optic wavelength down-conversion leads to effective acoustical apertures very large compared to the physical size. Second, the unit cells are not synchronized electronically and thus the complexity of the metasurface increases only linearly with the number of unit cells, which is a significantly slower increase compared to conventional synchronized arrays. This work shows that these advantages lead to compact acoustic cameras providing image resolutions higher than possible with conventional acoustic imaging methods.

Ultimate lateral pressures exerted on buried pipelines by the initiation of submarine landslides

Submarine slope instabilities are considered one of the major threats for offshore buried pipelines. This paper presents a novel method to evaluate the ultimate pressure acting on a buried pipeline during the liquefaction of an inclined seabed. Small-scale model tests with pipes buried at three different embedment ratios have been conducted at an enhanced centrifugal acceleration condition. A high-speed, high-resolution imaging system was developed to quantify the soil displacement field of the soil body and to visualize the development of the liquefied zone. The measured lateral pressures were compared with the hybrid approach proposed for the landslide–pipeline interaction in clay-rich material by Randolph and White (2012) and Sahdi et al. (2014). The hybrid approach is proved to be able to predict later pressures induced by the movement of (partially) liquefied sand on buried pipelines. It is found that the fluid inertia (fluid dynamics) component plays an important role when the non-Newtonian Reynolds number >~2 or the shear strain rate > 4.5 × 10−2 sec−1.

Bespoke flow experiments to capture the dynamics of coughs and sneezes

Here, we detail and analyse a set of tailored experiments to capture the flow dynamics of coughs and sneezes. Specifically, conventional particle tracking-based flow experiments are tailored to capture the wide range of spatial and temporal scales in the flow through the use of high-speed and high-resolution imaging systems. In doing so, we captured droplet velocities over a wide range of particle sizes with a large field-of-view in the order of a metre to capture the full flow field, which is challenging to achieve through conventional methods. A simultaneous direct measure of droplet sizing and velocity is also obtained through back-illuminated imaging experiments, albeit over a smaller spatial extent. A statistical assessment of the droplets’ flow-field reveals good agreement to prior works, now extending this over a much larger spatial extent. Through a statistical analysis of representative sneeze and cough samples, we highlight the potential of the presented experimental techniques to provide detailed flow dynamics. In particular, we observe that droplets are expelled over a significantly shorter period than the airflow generated in a cough; in contrast, droplets appear to be continuously expelled during the span of a sneeze. Furthermore, due to the lower momentum in coughs, droplets exhibit aerosolised behaviour at an earlier stage than sneezes, where the stronger flow-field expelled dictates the droplet dynamics through the bulk of the sneeze duration. These findings reveal crucial differences between coughs and sneezes, which are essential when modelling such flow accurately or designing pressure-driven simulators.

Multimodal high-resolution embryonic imaging with light sheet fluorescence microscopy and optical coherence tomography.

A high-resolution imaging system combining optical coherence tomography (OCT) and light sheet fluorescence microscopy (LSFM) was developed. LSFM confined the excitation to only the focal plane, removing the out of plane fluorescence. This enabled imaging a murine embryo with higher speed and specificity than traditional fluorescence microscopy. OCT gives information about the structure of the embryo from the same plane illuminated by LSFM. The co-planar OCT and LSFM instrument was capable of performing co-registered functional and structural imaging of mouse embryos simultaneously.

A novel bandpass filter fed antipodal tapered slot antenna for millimeter wave imaging

In this paper, we propose antipodal tapered slot antenna with integrated bandpass filter over 23.5–40 GHz for high resolution imaging applications. The novel antenna feed comprises of half mode substrate integrated waveguide and rectangular slots with isosceles trapezoidal variation. The feed section gives a passband over 23.5–40 GHz with S 11 <−10 dB and S 21 ≃0 dB. We present the design evolution procedure for the integrated filter antenna. The proposed antenna exhibits S 11 <−10 dB over the controlled bandwidth from 23.5 GHz to 40 GHz. We incorporate rectangular corrugations in the form of a staircase at the outer edges of the antenna and ground plane slots to achieve a stable gain and stable radiation pattern over the controlled bandwidth. The proposed antenna occupies a volume of 30.3 × 16 × 0.254 mm3, and is fabricated and tested. The measured results show good agreement with simulations. As compared to the state-of-the-art approaches, the proposed antenna is compact in size and exhibits a constant gain and stable radiation pattern over the operating bandwidth. We describe case studies to illustrate the application of the proposed antenna in a wideband imaging system for the detection of concealed objects and material defects. The reconstructed images obtained with the proposed antenna demonstrate its potential for use in high-resolution millimeter wave imaging systems.

A two-step channel mismatch estimation and compensation method for distributed MC SAR

ABSTRACT A distributed multichannel synthetic aperture radar system refers to a multichannel synthetic aperture radar system with channels distributed and installed at different locations on the platform. It is a promising system for high-resolution wide-swath imaging. The channels of the distributed multichannel synthetic aperture radar are sparsely distributed and have long cross-track baselines. The range-variant envelope migration and phase mismatch in the echoes between different channels are introduced by the long cross-track baselines and affect the performance of azimuth signal reconstruction. The sparsity of channels results in the poor correlation of data between channels, so the time-domain cross-correlation method typically used in azimuth multichannel synthetic aperture radar cannot be used in distributed multichannel synthetic aperture radar to estimate channel phase error directly. In this paper, the gain-phase error, sampling time delay and slant range difference introduced by cross-track baselines are modelled uniformly as channel mismatches. Firstly, a two-step channel mismatch estimation and compensation method for distributed multichannel synthetic aperture radar is proposed. Secondly, a range-variant envelope migration compensation method based on the chirp scaling principle is given. Thirdly, this paper also presents the processing of data rearrangement based on the distribution of spatial sampling points to make the time-domain cross-correlation method suitable for distributed multichannel synthetic aperture radar. Point target simulation and scene simulation are provided to show the effectiveness of the proposed methods.