High-resolution Imaging System Research Articles

The (R)evolution of Distributed Amplifiers: From Vacuum Tubes to Modern CMOS and GaN ICs

Broadband amplification of signals is desirable in many applications such as high-speed data communications, high-resolution imaging systems, optoelectronics, and instrumentation systems. Wide bandwidth is one of the prominent factors to be considered in designing such systems because it determines the system's ability to transfer high-data-rate information, transmit/receive short pulses, and process wide-band signals. Designing broadband amplifiers has always been challenging. The ever-increasing demand for higher data rates and low energy consumption in next-generation communication systems further complicates broadband amplifier design.

Novel Stereoscopic Optical System for Objectively Measuring Above-Surface Scar Volume-First-Time Quantification of Responses to Various Treatment Modalities.

Current approaches use subjective semiquantitative or cumbersome objective methodologies to assess physical characteristics of hypertrophic and keloid scars. This pilot study aimed to evaluate the accuracy and feasibility of a new stereoscopic optical and high-resolution 3-dimensional imaging system, for objectively measuring changes in above-surface scar volume after various interventions. Feasibility and accuracy were assessed by monitoring the above-surface scar volume of 5 scars in 2 patients for 5 successive months. Above-surface scar volume and Vancouver Scar Scale scores and the investigator and patient volume improvement assessment scores were assessed before and 12 weeks after last intervention. Scar volume measured by the imaging system correlated significantly with the gold standard (actual weight). The greatest volume reduction followed a combination of cryotherapy and intralesional triamcinolone acetonide and 5-fluorouracil injections in Patient 1 and a combination of pulse dye laser and intralesional triamcinolone acetonide injections in Patient 2. The new stereoscopic optical system is a valid, accurate, and practical objective method for assessing scar volume and for monitoring treatment response. It is more sensitive and accurate than semiquantitative objective scales. Further studies with a higher number of patients and scars are required to increase the measurement validity of the system.

Development of a high-resolution alpha-particle imaging system for detection of plutonium particles from the Fukushima Daiichi nuclear power plant

For the detection of plutonium particles released from the Fukushima Daiichi nuclear power plant, we developed a high-resolution alpha-particle imaging system. The detector of the alpha-particle imaging system consists of a thin ZnS(Ag) sheet, a light guide, and a high quantum efficiency 1-inch square position-sensitive photomultiplier tube (PSPMT). The ZnS(Ag) sheet was optically coupled to the PSPMT with a 1.5 mm thick light guide between them. The Anger principle was used for the position calculation of the alpha particles. The spatial resolution of the alpha-particle imaging detector was 0.45 mm full width at half maximum for 5.5 MeV alpha particles. The uniformity of the imaging detector in the central part of the field of view was ±7%. The detection efficiency was 76% for 5.5 MeV alpha particles. Although the background count rate was 8.1 counts per minute because of the collection and detection of alpha particles from radon daughters in the air, it could be decreased to 0.1 counts per minute if the detector surface was covered with paper. There was no increase in the background count rates of 137Cs gamma photons and 45Ca beta particles. We obtained high-resolution variable phantom images and particles of alpha emitters with the system. We conclude that the alpha-particle imaging system developed is promising for the detection of plutonium particles in samples collected near the Fukushima Daiichi nuclear power plant.

Single-frequency 3D synthetic aperture imaging with dynamic metasurface antennas.

Through aperture synthesis, an electrically small antenna can be used to form a high-resolution imaging system capable of reconstructing three-dimensional (3D) scenes. However, the large spectral bandwidth typically required in synthetic aperture radar systems to resolve objects in range often requires costly and complex RF components. We present here an alternative approach based on a hybrid imaging system that combines a dynamically reconfigurable aperture with synthetic aperture techniques, demonstrating the capability to resolve objects in three dimensions (3D), with measurements taken at a single frequency. At the core of our imaging system are two metasurface apertures, both of which consist of a linear array of metamaterial irises that couple to a common waveguide feed. Each metamaterial iris has integrated within it a diode that can be biased so as to switch the element on (radiating) or off (non-radiating), such that the metasurface antenna can produce distinct radiation profiles corresponding to different on/off patterns of the metamaterial element array. The electrically large size of the metasurface apertures enables resolution in range and one cross-range dimension, while aperture synthesis provides resolution in the other cross-range dimension. The demonstrated imaging capabilities of this system represent a step forward in the development of low-cost, high-performance 3D microwave imaging systems.

High-Resolution Multispectral Imaging and Analysis Systems for the Very-Long-Term Monitoring of Photographs, Paintings, Fabrics, Documents, Books, and Other Works of Artistic and Historical Importance

High-Resolution Multispectral Imaging and Analysis Systems for the Very-Long-Term Monitoring of Photographs, Paintings, Fabrics, Documents, Books, and Other Works of Artistic and Historical Importance

Toxicity-efficacy converting of ginseng combined with Fuzi Banxia incompatibility in heart failure stage of cor pulmonale

ObjectiveFuzi Banxia is one of eighteen antagonisms, previous studies have shown that the incompatibility could play special effects in the specific condition of diseases and appropriate compatible environment. The present study aims to evaluate the toxicity-efficacy of ginseng combined with Fuzi Banxia incompatibility intervening in the heart failure stage of cor pulmonale and to explore its mechanism. MethodsMonocrotaline (MCT)-induced cor pulmonale were used in this study. Ultra high-resolution small animal ultrasound real-time imaging system and the right heart catheterization were used to estimate cardiac function. Semi automatic biochemical analyzer was used to test myocardial enzyme LDH, CK, and CK-MB in serum. The heart tissues were stained with HE, and TUNEL assay was used to assess the pathomorphological changes and myocardial apoptosis. The expression of hypertrophy and apoptosis associated genes: ANP, BNP, β-MHC, Bax, and Bcl-2 in the right ventricle were determined by RT-PCR. ResultsFuzi Banxia combined with ginseng obviously attenuated mortality, decreased RVHI, and increased cardiac index; RVSP and mPAP were significantly reduced, and EF and FS were raised obviously; Myocardial enzymes LDH, CK, and CK-MB were pronounced attenuated; heart diameter reduced, right ventricular dilatation was significantly decreased, inflammatory cell infiltration notably reduced, and cardiac apoptosis rate was decreased obviously. Meanwhile, the expression of hypertrophy-related ANP, BNP, and β-MHC mRNA were up-regulated, the expression of apoptosis-related Bax mRNA was down-regulated, and the expression of anti-apoptosis-related Bcl-2 mRNA and Bcl-2/Bax ratio were up-regulated. ConclusionGinseng compatible environment could attenuate cardiac toxicity of Fuzi Banxia incompatibility intervening in the heart failure stage of cor pulmonale, and improve cardiac function, which may be related to the expression of hypertrophy and apoptosis associated genes, and thus delay the occurrence and development of heart failure.

Multiscale optical imaging of rare-earth-doped nanocomposites in a small animal model.

Rare-earth-doped nanocomposites have appealing optical properties for use as biomedical contrast agents, but few systems exist for imaging these materials. We describe the design and characterization of (i) a preclinical system for whole animal in vivo imaging and (ii) an integrated optical coherence tomography/confocal microscopy system for high-resolution imaging of ex vivo tissues. We demonstrate these systems by administering erbium-doped nanocomposites to a murine model of metastatic breast cancer. Short-wave infrared emissions were detected in vivo and in whole organ imaging ex vivo. Visible upconversion emissions and tissue autofluorescence were imaged in biopsy specimens, alongside optical coherence tomography imaging of tissue microstructure. We anticipate that this work will provide guidance for researchers seeking to image these nanomaterials across a wide range of biological models.

High-resolution W-band ISAR imaging system utilizing a logic-operation-based photonic digital-to-analog converter.

W-band inverse synthetic aperture radar (ISAR) imaging systems are very useful for automatic target recognition and classification due to their high spatial resolution, high penetration and small antenna size. Broadband linear frequency modulated wave (LFMW) is usually applied to this system for its de-chirping characteristic. However, nearly all of the LFMW generated in electronic W-band ISAR system are based on multipliers and mixers, suffering seriously from electromagnetic interference (EMI) and timing jitter. And photonic-assisted LFMW generator reported before is always limited by bandwidth or time aperture. In this paper, for the first time, we propose and experimentally demonstrate a high-resolution W-band ISAR imaging system utilizing a novel logic-operation-based photonic digital-to-analog converter (LOPDAC). The equivalent sampling rate of the LOPDAC is twice as large as the rate of the digital driving signal. Thus, a broadband LFMW with a large time aperture can be generated by the LOPDAC. This LFMW is up-converted to W band with an optical frequency comb. After photonic-assisted de-chirping processing and data processing to the echo, a high-resolution two-dimension image can be obtained. Experimentally, W-band radar with a time-bandwidth product (TBWP) as large as 79200 (bandwidth 8 GHz; temporal duration 9.9 us) is established and investigated. Results show that the two-dimension (range and cross-range) imaging resolution is ~1.9 cm × ~1.6 cm with a sampling rate of 100 MSa/s in the receiver.

Microsphere-assisted super-resolution imaging with enlarged numerical aperture by semi-immersion

Microsphere-assisted imaging is an extraordinary simple technology that can obtain optical super-resolution under white-light illumination. Here, we introduce a method to improve the resolution of a microsphere lens by increasing its numerical aperture. In our proposed structure, BaTiO3 glass (BTG) microsphere lenses are semi-immersed in a S1805 layer with a refractive index of 1.65, and then, the semi-immersed microspheres are fully embedded in an elastomer with an index of 1.4. We experimentally demonstrate that this structure, in combination with a conventional optical microscope, can clearly resolve a two-dimensional 200-nm-diameter hexagonally close-packed (hcp) silica microsphere array. On the contrary, the widely used structure where BTG microsphere lenses are fully immersed in a liquid or elastomer cannot even resolve a 250-nm-diameter hcp silica microsphere array. The improvement in resolution through the proposed structure is due to an increase in the effective numerical aperture by semi-immersing BTG microsphere lenses in a high-refractive-index S1805 layer. Our results will inform on the design of microsphere-based high-resolution imaging systems.

Recent developments in high-resolution-gamma-ray cargo-inspection technology

Under US Department of Homeland Security sponsorship, Spectral Labs Incorporated has developed a prototype high-resolution retrofit for an existing mobile VACIS, named the High-Resolution Imaging System (HiRIS). The legacy 256 NaI detectors in the VACIS detector column were replaced with 576 CsI detectors, more than doubling the pixel count. Using SiPMs to replace conventional PMTs allowed the packing of more detectors in the same VACIS detector enclosure. Legacy analog signal-processing electronics were replaced with advanced digital signal-processing electronics. Replacing gross counting in the legacy system with multichannel analysis of the counts from each detector will allow better control of detector crosstalk. The HiRIS detector modules were installed on a VACIS truck refurbished to as-new condition. Initial testing of the HiRIS prototype demonstrates enhanced spatial resolution by a factor of two as compared to the legacy system, without any degradation in throughput capability (20 containers per hour).

新真空太阳望远镜多波段高分辨率成像系统的视场定标

新真空太阳望远镜多波段高分辨率成像系统的视场定标

The applications of optical coherence tomography angiography in diabetic retinopathy

Optical coherence tomography angiography (OCTA), an extent function of traditional optical coherence tomography (OCT), is a non-invasive, high-resolution imaging system designed to display vascular networks. The fundamental principle of OCTA is to achieve the signal of blood flow based on the analysis of complex OCT signal, amplitude of OCT signal or phase of OCT signal. OCTA can display and monitor the vascular abnormalities in patients with diabetic retinopathy (DR), including microaneurysms, vessel density (VD), nonperfusion, neovascularization, and other lesions. OCTA offers a new and potential horizon in the monitor of the DR progress and evaluation of DR treatment.

Large-scale DNA organization is a prognostic marker of breast cancer survival.

Breast cancer is the leading cause of cancer-related deaths among women worldwide. We investigated whether changes in large-scale DNA organization (LDO) of tumor epithelial nuclei are an indicator of the aggressiveness of the tumor. We tested our algorithm on a set of 172 duplicates TMA cores samples coming from 95 breast cancer patients. Thirty-five patients died of breast cancer, and 60 were still alive 10years after surgery. Duplicates cores were used to create training and test set. The TMA slides were stained with Feulgen-thionin and imaged using our in-house high-resolution Imaging system. Automated segmentation of cell nuclei followed by manual selection of intact, in-focus nuclei resulted in an average of 50 cell nuclei per sample available for analysis. Using forward stepwise linear discriminant analysis, a combination of six features that combined linearly gave the best discrimination between the two groups of cells: cells collected from 'deceased' patients TMA specimens and cells collected from "survivors" patients TMA specimens. Five of these features measure the spatial organization of DNA chromatin. The resulting canonical score is named cell LDO score. A patient LDO score, percentage of cell nuclei with a cell LDO score higher than a predefined cutoff value, was processed for the specimens in the test set, and a cutoff value was defined to classify patients with a low or a high LDO score. Using this binary test, 82.1% of patients were correctly classified are "deceased" or "survivors," with a specificity of 79% and a sensitivity of 88%. The relative risk of death of an individual with a high LDO score was nine times higher than for a patient with a low LDO score. When testing the combination of LDO score, node status, histological grade, and tumor grade to predict breast cancer survival, LDO was the most significant predictor. LDO classification was also highly associated with survival for only grade 1 and 2 patients as well as for only grade 3 patients. Our result confirms the potential of LDO to measure phenotypic changes associated with more aggressive disease and could be evaluated to identify patients more likely to benefit from adjuvant therapies.

High-Resolution Wide-Swath Imaging of Spaceborne Multichannel Bistatic SAR With Inclined Geosynchronous Illuminator

Spaceborne bistatic synthetic aperture radar (SAR) system with an inclined geosynchronous (GEO) illuminator and a low-earth-orbit (LEO) receiver is capable of providing a vast area of surveillance and fine spatial resolution, which presents huge potentials for future earth observation. In this letter, inclined GEO–LEO azimuth multichannel SAR (MC-SAR) system for high-resolution wide-swath imaging is investigated. Starting from modeling geometry of inclined GEO–LEO bistatic MC-SAR, the signal model is analyzed in detail for the first time, and the equivalent positions of the received channels are obtained. Then, we found the spatial-variant residual phase error cannot be compensated accurately by conventional effective phase center (EPC) processing. Moreover, because of the complex bistatic configuration, the frequency-domain imaging algorithms become extremely difficult to achieve a well-focused and phase-preserved image. Meanwhile, the time-domain back-projection algorithm (BPA) faces with a technical challenge due to the nonuniform sampling in azimuth. To address these issues, a bistatic weighted BPA (BWBPA) for GEO–LEO MC-SAR is derived and presented. Without the procedure of EPC, the BWBPA can suppress azimuth ambiguities effectively and yield phase-preserved SAR images. Simulated data results show the validity of the presented method.

High axial resolution imaging system for large volume tissues using combination of inclined selective plane illumination and mechanical sectioning.

To resolve fine structures of biological systems like neurons, it is required to realize microscopic imaging with sufficient spatial resolution in three dimensional systems. With regular optical imaging systems, high lateral resolution is accessible while high axial resolution is hard to achieve in a large volume. We introduce an imaging system for high 3D resolution fluorescence imaging of large volume tissues. Selective plane illumination was adopted to provide high axial resolution. A scientific CMOS working in sub-array mode kept the imaging area in the sample surface, which restrained the adverse effect of aberrations caused by inclined illumination. Plastic embedding and precise mechanical sectioning extended the axial range and eliminated distortion during the whole imaging process. The combination of these techniques enabled 3D high resolution imaging of large tissues. Fluorescent bead imaging showed resolutions of 0.59 μm, 0.47μm, and 0.59 μm in the x, y, and z directions, respectively. Data acquired from the volume sample of brain tissue demonstrated the applicability of this imaging system. Imaging of different depths showed uniform performance where details could be recognized in either the near-soma area or terminal area, and fine structures of neurons could be seen in both the xy and xz sections.

Benthic Habitat Mapping Using Multispectral High-Resolution Imagery: Evaluation of Shallow Water Atmospheric Correction Techniques.

Remote multispectral data can provide valuable information for monitoring coastal water ecosystems. Specifically, high-resolution satellite-based imaging systems, as WorldView-2 (WV-2), can generate information at spatial scales needed to implement conservation actions for protected littoral zones. However, coastal water-leaving radiance arriving at the space-based sensor is often small as compared to reflected radiance. In this work, complex approaches, which usually use an accurate radiative transfer code to correct the atmospheric effects, such as FLAASH, ATCOR and 6S, have been implemented for high-resolution imagery. They have been assessed in real scenarios using field spectroradiometer data. In this context, the three approaches have achieved excellent results and a slightly superior performance of 6S model-based algorithm has been observed. Finally, for the mapping of benthic habitats in shallow-waters marine protected environments, a relevant application of the proposed atmospheric correction combined with an automatic deglinting procedure is presented. This approach is based on the integration of a linear mixing model of benthic classes within the radiative transfer model of the water. The complete methodology has been applied to selected ecosystems in the Canary Islands (Spain) but the obtained results allow the robust mapping of the spatial distribution and density of seagrass in coastal waters and the analysis of multitemporal variations related to the human activity and climate change in littoral zones.

Improved Water-Resistance Test Methods Utilizing a Multispectral Imaging System to Quantify Black and Color Ink Bleeding for Plain Paper Office and Legal Documents Printed with Pigment- and Dye-Based Inkjet Inks

Current ISO standards that pertain to water-resistance testing with inkjet prints were developed for moisture-impermeable RC photo papers and do not take into account the kinds of ink diffusion behavior that can occur with inkjet printing on highly absorbent plain papers, especially with dye-based inks. Contact with water with plain paper documents can result in significant lateral ink bleeding, migration of inks through the paper to the backside of the sheet, transfer of ink from one sheet to adjacent sheets, and two-way transfer of inks with double-sided printed documents. Shipping labels and envelopes can become illegible should they become wet, and Barcodes and QR codes may be rendered completely unreadable. This study attempts to better understand the water-resistance behavior of plain paper documents printed with dye-based and pigment inkjet inks. The use of high-resolution multispectral imaging and colorimetric analysis systems to provide a quantitative assessment of ink bleeding, migration, and ink transfer to adjacent pages is explored as an alternative to the subjective, qualitative, water-resistance evaluation methods specified in current ISO standards.

Long-term Live Imaging Device for Improved Experimental Manipulation of Zebrafish Larvae.

The zebrafish larva is an important model organism for both developmental biology and wound healing. Further, the zebrafish larva is a valuable system for live high-resolution microscopic imaging of dynamic biological phenomena in space and time with cellular resolution. However, the traditional method of agarose encapsulation for live imaging can impede larval development and tissue regrowth. Therefore, this manuscript describes the zWEDGI (zebrafish Wounding and Entrapment Device for Growth and Imaging), which was designed and fabricated as a functionally compartmentalized device to orient larvae for high-resolution microscopy while permitting caudal fin transection within the device and subsequent unrestrained tail development and re-growth. This device allows for wounding and long-term imaging while maintaining viability. Given that the zWEDGI mold is 3D printed, the customizability of its geometries make it easily modified for diverse zebrafish imaging applications. Furthermore, the zWEDGI offers numerous benefits, such as access to the larva during experimentation for wounding or for the application of reagents, paralleled orientation of multiple larvae for streamlined imaging, and reusability of the device.

Application of Speckle-Tracking Echocardiography in an Experimental Model of Isolated Subendocardial Damage

The subendocardium is highly vulnerable to damage and is thus affected even in subclinical disease stages. Therefore, methods reflecting subendocardial status are of great clinical relevance for the early detection of cardiac damage and the prevention of functional impairment. The aim of this study was to investigate the potentialability of myocardial strain parameters to evaluate changes within the subendocardium. Male 129/Sv mice were injected with isoproterenol (ISO; n=32) to induce isolated subendocardial fibrotic lesions or saline as appropriate control (n=15). Transthoracic echocardiography was performed using a 30-MHz linear-frequency transducer coupled to a high-resolution imaging system, and acquired images were analyzed for conventional and strain parameters. The degree of collagen content within the different cardiac layers was quantified by histologic analysis and serum levels of tissue inhibitor of metalloproteinase-1, abiomarker for fibrosis, were assessed. ISO treatment induced a marked increase in subendocardial collagen content in response to cell loss (control vs ISO, 0.6±0.3% vs 5.8±0.9%; P<.001) and resulted in a moderate increase in left ventricular wall thickness with preserved systolic function. Global longitudinal peak strain (LS) and longitudinal strain rate were significantly decreased in ISO-treated animals (LS, -15.49% vs -11.49% [P=.001]; longitudinal strain rate, -4.81 vs -3.88sec-1 [P<.05]), whereas radial and circumferential strain values remained unchanged. Global LS was associated with subendocardial collagen content (r=0.46, P=.01) and tissue inhibitor of metalloproteinase-1 serum level (r=0.52, P<.05). Further statistical analyses identified global LS as a superior predictor for the presence of subendocardial fibrosis (sensitivity, 84%; specificity, 80%; cutoff value, -14.4%). Assessment of LS may provide a noninvasive method for the detection of subendocardial damage and may consequently improve early diagnosis of cardiac diseases.

Characterization of a sCMOS-based high-resolution imaging system

The detection system is a key part of any imaging station. Here the performance of the novel sCMOS-based detection system installed at the ID17 biomedical beamline of the European Synchrotron Radiation Facility and dedicated to high-resolution computed-tomography imaging is analysed. The system consists of an X-ray-visible-light converter, a visible-light optics and a PCO.Edge5.5 sCMOS detector. Measurements of the optical characteristics, the linearity of the system, the detection lag, the modulation transfer function, the normalized power spectrum, the detective quantum efficiency and the photon transfer curve are presented and discussed. The study was carried out at two different X-ray energies (35 and 50 keV) using both 2× and 1× optical magnification systems. The final pixel size resulted in 3.1 and 6.2 µm, respectively. The measured characteristic parameters of the PCO.Edge5.5 are in good agreement with the manufacturer specifications. Fast imaging can be achieved using this detection system, but at the price of unavoidable losses in terms of image quality. The way in which the X-ray beam inhomogeneity limited some of the performances of the system is also discussed.