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Higher dimensional optical imaging has seen remarkable growth in the past decade. As a representative method, multiplexed structured illumination (MSI) has been widely introduced for its ultra-high resolution of high-dimensional information. In this letter, an imaging framework for recovering higher dimensional image data, which terms quadrature multiplexed structured illumination (QMSI), is proposed and demonstrated. QMSI incorporates the illumination pattern spatial phase information as a new parameter into the encoding process. This strategy can double the frequency spectrum utilization without any overhead compared to MSI, which means it can double the image sequence depth or image spatial resolution. As a proof of concept, we demonstrate the performance of QMSI by experiments on multispectral imaging.

Single-pixel imaging (SPI) has attracted increasing attention in recent years because of its advantages in imaging systems. However, a low reconstruction quality and a long reconstruction time have hindered the development of SPI. Hence, in this study, we propose a Zernike SPI (ZSPI) technique to reduce the number of illumination patterns and reconstruction time whilst retaining robustness. First, the ZSPI technique was theoretically demonstrated. Phase-shifting Zernike moment projections were used to illuminate the target and an inverse Zernike transform was used to reconstruct the desired image. In order to prove the feasibility, numerical simulations were carried out with different sample ratios (SRs) ranging from 0.1 to 0.3; an acceptable reconstruction appeared at approximately 0.1. This result indicated that ZSPI could obtain satisfactory reconstruction results at low SRs. Further simulation and physical experiments were compared with different reconstruction algorithms, including noniterative, linear iterative, and nonlinear iterative methods under speckle modulation patterns at a sample of 0.1 in terms of different targets. The results revealed that ZSPI had a higher imaging quality and required less imaging time, particularly for low-frequency targets. The method presented in this study has advantages for the high-efficiency imaging of low-frequency targets, which can provide a new solution for the SPI method.

Systems neuroscience is focused on how ensemble properties in the brain, such as the activity of neuronal circuits, gives rise to internal brain states and behavior. Many of the studies in this field have traditionally involved electrophysiological recordings and computational approaches that attempt to decode how the brain transforms inputs into functional outputs. More recently, systems neuroscience has received an infusion of approaches and techniques that allow the manipulation (e.g., optogenetics, chemogenetics) and imaging (e.g., two-photon imaging, head mounted fluorescent microscopes) of neurons, neurocircuits, their inputs and outputs. Here, we will review novel approaches that allow the manipulation and imaging of specific molecular mechanisms in specific cells (not just neurons), cell ensembles and brain regions. These molecular approaches, with the specificity and temporal resolution appropriate for systems studies, promise to infuse the field with novel ideas, emphases and directions, and are motivating the emergence of a molecularly oriented systems neuroscience, a new discipline that studies how the spatial and temporal patterns of molecular systems modulate circuits and brain networks, and consequently shape the properties of brain states and behavior.

In this manuscript, we have launched a study on the completely nonsymmetric freeform optical system with neither rotational symmetry nor planar symmetry. An off-axis three-mirror freeform optical system with nonsymmetric geometry is proposed and a direct design method is developed for the nonsymmetric freeform optical system. The design field points are sampled across the full FOV to control the imaging quality and object–image relationship. In this system, the center of the image plane is greatly away from the plane determined by the centers of the three mirrors. This nonsymmetric system with F/1.3, a focal length of 50 mm, and an 8° × 6° field of view can achieve imaging quality close to the diffraction limit. This work provides a feasible nonsymmetric system design idea for the optical community.

For the detection of weak signals, photon counting technology has attracted much attention. In this paper, a method based on photon counting is experimentally demonstrated to realize corona discharge detection at solar-blind ultraviolet (UV) wavelength. In our setup, a solar-blind UV optical filter and a Te-Cs cathode are used to eliminate the effects of light with undesired wavelengths, i.e., outside of the solar-blind band. A two-stage microchannel plate with a high voltage can achieve a gain of up to 106. A phosphor screen coupled with a CMOS can capture complete images without image distortion. By using an ICMOS, the setup can detect single-photon events. Then, applying photon counting statistics, a theoretical probability model of the photon numbers is obtained. Meanwhile, through analyzing the structure of the photon events considering both pixel and temporal resolution, two photon counting algorithms are proposed. Through experiments with an UV light source, the algorithm based on temporal resolution is proved to be more accurate. Finally, through an experiment with a corona discharge device, a solar-blind photon counting image is captured, and the photon number is calculated through the proposed counting algorithm. The probability curve of the practical photon numbers is acquired via several experiments carried out at the same conditions, which proves the accuracy of the setup and algorithm when compared with the theoretical probability model. Therefore, the proposed method can provide a scientific evaluation for corona detection.

This paper describes the construction of a low-cost, open-source system for imaging the contents of multi-well plates., An inexpensive system for automated imaging of the contents of 12-, 24- and 96-well plates has been built. The xyz stage is constructed from parts from a light-duty computer numerical control wood-carving/engraving machine, and the Arduino-based board was wired so that it can trigger still images or movies though a microscope-mounted digital camera. The translation stage provides reproducible three-dimensional movement of the sample over a volume of 160 mm in x, 100 mm in y and 40 mm in z. A Python script generates the G-code command file that scans the plate and collects a series of z-stacked images of each sample. A second Python script automates the calculation of images with a digitally enhanced depth of field. The imaging system is currently being used to facilitate screening for protein crystals, but it could be used to automate the imaging of many other types of samples in multi-well plates.

γ-ray spectrometry is a well-known technique in environmental radioactivity measurements where easily handled systems are needed. Scintillators coupled to a photomultiplier tube (PMT), are typically favoured over solid-state detectors as mobile spectrometers. Replacing PMT with position sensitive devices represents an innovative solution that provides the evaluation of the interaction point of the incident radiation. The knowledge of spectrometry as a function of the depth of interaction (DoI) assures a better understanding of the spectrum and a more reliable identification of the source. In this paper, the efficiency of a simple DoI estimator has been studied using a CRY018 monolithic crystal coupled to a multi-anode photomultiplier tube. The DoI estimator has been evaluated studying charge distributions and the dependency of spectrometric properties on the DoI has been qualitatively analyzed. The estimator has shown to be highly sensitive to the DoI, enabling a better understanding of the internal interaction processes of light and an efficient rejection of the background component on the spectra. The novelty of this work lies in the application of the DoI selection in spectrometry made available by the use of MAPMT. The proposed method is practical since it does not require complicated hardware solutions or complex computational procedures.

The resolution limit, which characterizes the resolution power of an optical imaging system, is defined as the resolvable minimum-separation between two points. In classical optical imaging, the resolution limit is given by the Rayleigh diffraction limit. In this paper, we propose a concept of critical resolution, which is used to describe the minimum separation of two adjacent objects that an imaging system can resolve. The critical resolution of pseudo-thermal ghost imaging (PGI) system is analyzed. To quantify the critical resolution, we develop a mathematical formula from which one can evaluate whether a prescribed object can be resolved in a PGI system. The evolution process from critical resolution to resolution limit is presented when the object size towards to zero. The results show that the resolution limit of PGI system is 1.98 times the speckle size. Our results can not only promote the development of GI technology, but also provide theoretical guidance for the design of GI system.

Fourier ptychographic microscopy (FPM) is a recently developed microscope technology that overcomes the resolution limit of a low numerical aperture objective lens by employing angular varying illuminations. Combining the concepts of ptychography, synthetic aperture, and phase retrieval, FPM achieves high-resolution, wide-field, and quantitative phase imaging at the same time. In typical FPM systems, the angular varying illuminations are achieved with LED arrays whose positional misalignments bring significant errors in the reconstruction procedure. In previous studies, several LED array alignment methods are developed, which iteratively recover the positional misalignment parameters during the reconstruction. These methods consume additional calculations in FPM reconstruction and may not be practical in other microscopy system. In this work, we represent a preprocessing LED array alignment method by accurately localizing the brightfield area on the sample plane. By applying particle swarm optimization method and random sample consensus method, the global misalignment parameters can be estimated with high accuracy and speed. Both numerical simulations and actual system experiments are carried out to evaluate the effectiveness of our method and the results show that the reconstruction quality of high-resolution images is significantly improved by using our method.

Fourier ptychography microscopy (FPM) is a lately developed technique, which achieves wide field, high resolution, and phase imaging, simultaneously. FPM stitches together the captured low-resolution images corresponding to angular varying illuminations in Fourier domain utilizing the concept of synthetic aperture and phase retrieval algorithms, which can surpass the space-bandwidth product limit of the objective lens and reconstruct a high-resolution complex image. In general FPM system, the LED source is important for the reconstructed quality and it is sensitive to the positions of each LED element. We find that the random positional deviations of each LED element can bring errors in reconstructed results, which is relative to a feedback parameter. To improve the reconstruction rate and correct random deviations, we combine an initial phase guess and a feedback parameter based on differential phase contrast and extended ptychographical iterative engine to propose an optimized iteration process for FPM. The simulated and experimental results indicate that the proposed method shows the reliability and validity towards the random deviations yet accelerates the convergence. More importantly, it is verified that this method can accelerate the convergence, reduce the requirement of LED array accuracy, and improve the quality of the reconstructed results.

We constructed an imaging system to measure the concentration of acetone gas by acetone reduction using secondary alcohol dehydrogenase (S-ADH). Reduced nicotinamide adenine dinucleotide (NADH) was used as an electron donor, and acetone was imaged by fluorescence detection of the decrease in the autofluorescence of NADH. In this system, S-ADH–immobilized membranes wetted with buffer solution containing NADH were placed in a dark box, and UV-LED excitation sheets and a high-sensitivity camera were installed on both sides of the optical axis to enable loading of acetone gas. A hydrophilic polytetrafluoroethylene (H-PTFE) membrane with low autofluorescence was used as a substrate, and honeycomb-like through-hole structures were fabricated using a CO2 laser device. After loading the enzyme membrane with acetone gas standards, a decrease in fluorescence intensity was observed in accordance with the concentration of acetone gas. The degree of decrease in fluorescence intensity was calculated using image analysis software, it was possible to quantify acetone gas at concentrations of 50–2000 ppb, a range that includes the exhaled breath concentration of acetone in healthy subjects. We applied this imaging system to measure the acetone gas in the air exhaled by a healthy individual during fasting.

Time-gated (TG) fluorescence imaging (TGFI) has attracted increasing attention within the biological imaging community, especially during the past decade. With rapid development of light sources, image devices, and a variety of approaches for TG implementation, TGFI has demonstrated numerous biological applications ranging from molecules to tissues. The paper presents inclusive TG implementation mainly based on optical choppers and electronic units for synchronization of fluorescence excitation and emission, which also serves as guidelines for researchers to build suited TGFI systems for selected applications. Note that a special focus will be put on TG implementation based on optical choppers for TGFI of long-lived probes (lifetime range from microseconds to milliseconds). Biological applications by TG imaging of recently developed luminescent probes are described.

We performed a detailed comparative study of the parametric high degree (cubic, fourth, and fifth) power phase apodization on compensation defocusing and chromatic aberration in the imaging system. The research results showed that increasing the power degree of the apodization function provided better independence (invariance) of the point spread function (PSF) from defocusing while reducing the depth of field (DOF). This reduction could be compensated by increasing the parameter α, however, this led to an increase in the size of the light spot. A nonlinear relationship between the increase in the DOF and spot size was shown (due to a small increase in the size of the light spot, the DOF can be significantly increased). Thus, the search for the best solution was based on a compromise of restrictions on the circle of confusion (CoC) and DOF. The modeling of color image formation under defocusing conditions for the considered apodization functions was performed. The subsequent deconvolution of the resulting color image was demonstrated.

The use of 3D plant models for high-throughput phenotyping is increasingly becoming a preferred method for many plant science researchers. Numerous camera-based imaging systems and reconstruction algorithms have been developed for the 3D reconstruction of plants. However, it is still challenging to build an imaging system with high-quality results at a low cost. Useful comparative information for existing imaging systems and their improvements is also limited, making it challenging for researchers to make data-based selections. The objective of this study is to explore the possible solutions to address these issues. We introduce two novel systems for plants of various sizes, as well as a pipeline to generate high-quality 3D point clouds and meshes. The higher accuracy and efficiency of the proposed systems make it a potentially valuable tool for enhancing high-throughput phenotyping by integrating 3D traits for increased resolution and measuring traits that are not amenable to 2D imaging approaches. The study shows that the phenotype traits derived from the 3D models are highly correlated with manually measured phenotypic traits (R2 > 0.91). Moreover, we present a systematic analysis of different settings of the imaging systems and a comparison with the traditional system, which provide recommendations for plant scientists to improve the accuracy of 3D construction. In summary, our proposed imaging systems are suggested for 3D reconstruction of plants. Moreover, the analysis results of the different settings in this paper can be used for designing new customized imaging systems and improving their accuracy.

We have developed an instrument and a method to perform in vivo hyperspectral imaging of the human iris in order to quantitatively measure its spectral reflectance. Understanding age-related changes in the reflectance properties of the iris is important for multiple aspects of vision research. The images are acquired in the spectral range 450–810nm from three healthy volunteers. The spectral resolution is equal to 30nm, while each image of 1024×768 pixels has a spatial resolution of 22.5μm. The instrument appears suitable for measuring iris pigmentation changes over time. These measurements could offer new diagnostic possibilities in ophthalmology.

The purpose of this study is to evaluate the accuracy and reproducibility of the IsoCal geometric calibration system for kilovoltage (kV) and megavoltage (MV) imagers on Varian C‐series linear accelerators (linacs). IsoCal calibration starts by imaging a phantom and collimator plate using MV images with different collimator angles, as well as MV and kV images at different gantry angles. The software then identifies objects on the collimator plate and in the phantom to determine the location of the treatment isocenter and its relation to the MV and kV imager centers. It calculates offsets between the positions of the imaging panels and the treatment isocenter as a function of gantry angle and writes a correction file that can be applied to MV and kV systems to correct for those offsets in the position of the panels. We performed IsoCal calibration three times on each of five Varian C‐series linacs, each time with an independent setup. We then compared the IsoCal calibrations with a simplified Winston‐Lutz (WL)‐based system and with a Varian cubic phantom (VC)‐based system. The maximum IsoCal corrections ranged from 0.7 mm to 1.5 mm for MV and 0.9 mm to 1.8 mm for kV imagers across the five linacs. The variations in the three calibrations for each linac were less than 0.2 mm. Without IsoCal correction, the WL results showed discrepancies between the treatment isocenter and the imager center of 0.9 mm to 1.6 mm (for the MV imager) and 0.5 mm to 1.1 mm (for the kV imager); with IsoCal corrections applied, the differences were reduced to 0.2 mm to 0.6 mm (MV) and 0.3 mm to 0.6 mm (kV) across the five linacs. The VC system was not as precise as the WL system, but showed similar results, with discrepancies of less than 1.0 mm when the IsoCal corrections were applied. We conclude that IsoCal is an accurate and consistent method for calibration and periodic quality assurance of MV and kV imaging systems. PACS numbers: 87.55.Qr, 87.56.Fc

The paper presents the calibration activity on the imaging system of the MINLU instrument, an autonomous sensor suite designed for monitoring light pollution using commercial off-the-shelf components. The system is extremely compact and with an overall mass below 3 kg can be easily installed as a payload for drones or sounding balloons. Drones and air balloons can in fact play an important role in completing upward light emission measurement from satellites allowing an increased spatial and time resolution from convenient altitudes and positions. The proposed system can efficiently measure the luminous intensity and the spectral power density of on-ground emissions providing a useful tool to identify polluting sources and to quantify upward light flux. The metrological performance of the imaging system has been verified through an extensive laboratory test activity using referenced light sources: the overall uncertainty of the multi-luminance meter has been calculated to be 7% of the reading, while the multi-spectrometer has shown a full width at half maximum (FWHM) equal to 10 nm within the measuring range between 400 nm and 700 nm. When operating at an altitude of 200 m, the system can achieve a horizontal resolution at a ground level of 0.12 m with a wavelength resolution able to identify the different lamp technology of outdoor light sources, including light-emitting diode (LED) lights that are undetected by satellites.

Multi-pixel photon counting detectors can produce images in low-light environments based on passive photon counting technology. However, the resulting images suffer from problems such as low contrast, low brightness, and some unknown noise distribution. To achieve a better visual effect, this paper describes a denoising and enhancement method based on a block-matching 3D filter and a non-subsampled contourlet transform (NSCT). First, the NSCT was applied to the original image and histogram-equalized image to obtain the sub-band low- and high-frequency coefficients. Regional energy and scale correlation rules were used to determine the respective coefficients. Adaptive single-scale retinex enhancement was applied to the low-frequency components to improve the image quality. The high-frequency sub-bands whose line features were best preserved were selected and processed using a symbol function and the Bayes-shrink threshold. After applying the inverse transform, the fused photon counting image was subjected to an improved block-matching 3D filter, significantly reducing the operation time. The final result from the proposed method was superior to those of comparative methods in terms of several objective evaluation indices and exhibited good visual effects and details from the objective impression.

Purpose. Cone beam computed tomography (CBCT) image quality is limited by scattered photons. Monte Carlo (MC) simulations provide the ability of predicting the patient-specific scatter contamination in clinical CBCT imaging. Lengthy simulations prevent MC-based scatter correction from being fully implemented in a clinical setting. This study investigates the combination of using fast MC simulations to predict scatter distributions with a ray tracing algorithm to allow calibration between simulated and clinical CBCT images. Material and methods. An EGSnrc-based user code (egs_cbct), was used to perform MC simulations of an Elekta XVI CBCT imaging system. A 60keV x-ray source was used, and air kerma scored at the detector plane. Several variance reduction techniques (VRTs) were used to increase the scatter calculation efficiency. Three patient phantoms based on CT scans were simulated, namely a brain, a thorax and a pelvis scan. A ray tracing algorithm was used to calculate the detector signal due to primary photons. A total of 288 projections were simulated, one for each thread on the computer cluster used for the investigation. Results. Scatter distributions for the brain, thorax and pelvis scan were simulated within 2% statistical uncertainty in two hours per scan. Within the same time, the ray tracing algorithm provided the primary signal for each of the projections. Thus, all the data needed for MC-based scatter correction in clinical CBCT imaging was obtained within two hours per patient, using a full simulation of the clinical CBCT geometry. Conclusions. This study shows that use of MC-based scatter corrections in CBCT imaging has a great potential to improve CBCT image quality. By use of powerful VRTs to predict scatter distributions and a ray tracing algorithm to calculate the primary signal, it is possible to obtain the necessary data for patient specific MC scatter correction within two hours per patient.

In this paper, the practical tradeoffs for designing submillimeter wavelength imagers based on optomechanical systems combined with focal plane arrays (FPAs) are presented. The architecture of these systems differs for operation at short and long ranges. General formulas to derive the effective field of view of diffraction limited quasi-optical systems in these two scenarios are shown. These formulas can be used to evaluate the performance of a specific optical system implementation. As an application example, we present the design of an optomechanical system that can operate at both ranges in a modular approach. The presented implementation achieves an effective field of view, which is $\hbox{70}\%$ of the canonical one. The proposed solution consists of a linear FPA of eight active transceivers combined with a raster scan technique. The system for short-range scenario is a side-fed dual-reflector Dragonian architecture because of its good scanning performance when illuminated by an FPA. Thanks to the system's small aperture, the scanner is arranged after the primary mirror, without causing additional scan loss. The Dragonian system is then used to illuminate a confocal dual-reflector architecture to magnify its aperture, and can be used in the long-range scenario. The scanner in this case is before the main aperture and it has to be considered in the performance optimization of the optical system since it adds phase aberration loss.

Terahertz electromagnetic radiation (from 0.1 THz up op 10 THz) lies in the boundary region between microwave frequencies and infrared and has attracted a great deal of attention in recent years due to all its interesting and remarkable properties. This frequency range is notable for its ability to penetrate non-conductive materials (clothes, paper, cardboard and plastics) with low attenuation, providing a high resolution in imaging techniques, in addition to offering higher resolution than other lower frequencies according to their lower wavelength. A very important aspect to take into account is that, despite being at high frequencies, it is a non-ionizing energy, so it is not harmful to the health of humans. There are numerous applications at Terahertz frequencies, for example making use of their property to be reflected after hitting with metals, arise applications related to people security, such as imaging systems for detection of concealed weapons under clothes. The work presented is this thesis will be focused in the technologies required for this application and its main objective is to acquire the necessary knowledge and experience on Terahertz frequencies to make these technologies available to the national R&D&I system, contributing to its development and evolution. It is remarkable to say that in these high frequencies there are several technology limitations such as: the reduced dimensions of the circuits due to the small wavelength, a very limited number of companies offering components in these bands and limitations in manufacturing and measuring equipment in terms of high cost, higher performance and demanded accuracy. All this restrictions make more complex the development of systems at these frequencies compared to lower frequencies. This work has contributed to extend the previous background of our research group from lower microwave frequencies to reach the W band, starting point of the Terahertz range. Focusing the work in W band which ranges from 75 up to 110 GHz, a comparison between two types of active and passive Imaging systems has been done, analyzing their characteristic parameters. For that, studies have been carried out on the available technologies and several designs of structures and circuits necessary to implement them have been developed. Thus, low noise amplifiers, medium power amplifier, RF power detectors and total power radiometer combining the previous ones have been characterized and integrated in waveguide assemblies. A coupled microstrip band pass filter has been designed and manufactured, as well as different versions of detectors based on a zero bias diode, which has been previously modeled. In addition, it has been modeled the low frequency noise of diodes part of already available detectors in lower frequency, as a preliminary step to afford later the same task in W band detectors. To have a system perspective, beyond the individual components, some basic experiments have been carried out to evaluate reliability of EM simulation procedures of imaging scenarios and its connection to circuit and system simulations. RESUMEN: La radiación electromagnética de Terahercios (desde 0.1 THz hasta 10 THz), que se sitúa en la región limítrofe entre las frecuencias de microondas y el infrarrojo, ha suscitado un gran interés en los últimos años debido a sus interesantes y destacables propiedades. Este rango de frecuencias destaca por su gran capacidad de penetración en materiales no conductores (ropa, papel, cartón y plásticos) con una baja atenuación, obteniendo una alta resolución en técnicas de Imaging, además de ofrecer mayor resolución que otras frecuencias inferiores, de acuerdo con su menor longitud de onda. Un aspecto muy importante a tener en cuenta, es que a pesar de encontrarnos en frecuencias elevadas, se trata de una energía no ionizante, por lo que no es perjudicial para la salud de los seres humanos. Existen numerosas aplicaciones a frecuencias de Terahercios y haciendo uso de la propiedad de reflejar la radiación emitida al chocar con metales, surgen aplicaciones relacionadas con la seguridad de las personas, tales como sistemas de “Imaging” para detección de armas ocultas bajo la ropa. El trabajo presentado es esta tesis se enfocará en las tecnologías necesarias para el desarrollo de dicha aplicación y su objetivo principal es adquirir el conocimiento y la experiencia necesarios sobre las frecuencias de Terahercios para poner estas tecnologías a disposición del sistema I+D+i a nivel nacional, haciendo aportaciones a su evolución y desarrollo. Cabe destacar que, en estas elevadas frecuencias, existen varias limitaciones tecnológicas tales como: las dimensiones reducidas de los circuitos debido a la pequeña longitud de onda, un número limitado de empresas que ofrezcan componentes en estas bandas y las limitaciones en equipos en términos de coste elevado, mayor rendimiento y una precisión más exigente. Todas estas restricciones hacen más complejo el desarrollo de sistemas a estas frecuencias comparado con frecuencias más bajas de microondas. Por este motivo el trabajo ha contribuido al avance y la extensión de los rangos frecuenciales cubiertos hasta ahora por las tecnologías de fabricación y medida con las que se tenía experiencia en nuestro grupo de investigación, llevándonos a cubrir la banda W, puerta de los Terahercios. Centrándonos en el trabajo en la banda W, comprendida entre 75 y 110 GHz, se ha realizado una comparativa entre dos tipos de sistemas de Imaging, activos y pasivos, analizando sus parámetros característicos. Y para ello, se han llevado a cabo estudios sobre las tecnologías disponibles y se han desarrollado los diseños de estructuras y circuitos necesarios para implementarlos. Así, se han caracterizado e integrado en montajes con accesos en guía de onda de amplificadores de bajo ruido, de media potencia, detectores de RF y radiómetro de potencia total combinando los anteriores. Se han diseñado y fabricado un filtro de líneas acopladas, así como diferentes versiones de detectores basados en un diodo zero bias, el cual ha sido previamente modelado. Además se ha modelado el ruido en baja frecuencia de diodos que forman parte de detectores ya disponibles en más baja frecuencia, como paso previo para hacerlo después en banda W. Para tener una perspectiva de sistema, más allá de los componentes individuales, se han llevado a cabo algunos experimentos sencillos para evaluar la fiabilidad de los procedimientos de simulación EM de los escenarios de obtención de imágenes y su interacción con simulaciones de circuitos y sistemas. I would like to thank mainly the financial support provided by the Spanish government through project CONSOLIDER-INGENIO CSD2008-00068 (TERASENSE) and the University of Cantabria Industrial Doctorate programme 2014, project: “Estudio y Desarrollo de Tecnologías para Sistemas de Telecomunicación a Frecuencias Milimétricas y de Terahercios con Aplicación a Sistemas de Imaging en la Banda 90 GHz-100GHz”. Additional financial support was provided by the Spanish government through projects CONSOLIDER-INGENIO CSD2010-00064, CSD2008-00066, FEDER co-founded TEC2011-29126-C03-01, TEC2011-29264-C03-01, TEC2010-21496-C03-01 and TEC2014-58341-C4-1-R.

Providing consistently high-eating-quality meat products to consumers is crucial for the meat industry. Inconsistent meat tenderness has been identified as one of the major quality-related challenges for the meat industry. Thus, development of a precise and consistent method to predict meat tenderness will greatly benefit the meat industry by enabling it to ensure a constant high-quality meat supply to consumers. A novel noninvasive anisotropic image scanning technology has been recently developed to evaluate and predict microstructural and physicochemical changes in muscle. Thus, the objective of this study was to evaluate the efficacy of the novel anisotropic imaging system in assessing meat tenderness during postmortem aging periods. In this study, loins (Musculus longissimus lumborum) from one side of three beef carcasses were removed at 1-day postmortem. Beef samples were divided into four equal sections, and four aging times (7, 14, 21, and 28 days) were randomly assigned to each section. Two steaks were collected from each section; one steak was used for meat tenderness measurement (using the Warner-Bratzler shear force—WBSF) after each assigned aging time. The other steak was scanned using the anisotropic imaging system to analyze the muscle structural change. The results showed that as the aging period increased, both the WBSF and reflectance results decreased (p < 0.05), indicating an improvement in meat tenderness with aging. Furthermore, the WBSF and reflectance results showed a strong correlation with an r2 value of 0.995 (p = 0.003). This result suggests that the scattering anisotropy imaging method can be used as a viable noninvasive prediction tool for determining the extent of meat tenderization.

International audience; This paper deals with the experimental characterization of an array probe dedicated to the eddy current imaging of sub-millimetric surface breaking defects appearing in bore holes of metallic parts. The probe is constituted of a large inducer generating an uniformly oriented EC flow within the inspected material, and a sensing array probe featuring bobbin coils to sense the radial component of the magnetic field resulting from the eddy currents/defects interactions within the wall of the bore hole. The probe was designed with accurate defect characterization in view, i.e. to provide multi-frequency and high spatial resolution images with a reduced acquisition time, so as to enhance the informative content of the acquired eddy current data. An experimental set-up was build in order to validate the imaging performances of such a probe. A prototype featuring a large inducer and a single sensing coil which can be accurately positioned in the sensing area, has been developed in order to evaluate the sensing performances as well as to study the influence of the sensing array configuration on the imaging performances. The experimental results demonstrate a good sensing ability of the designed probe in the 10-800 kHz frequency range, with peak-signal-to-noise ratios higher than 36 dB at 10 kHz (and 62 dB at 800 kHz) for defects featuring dimensions as small as 0.4 mm × 0.2 mm × 0.2 mm. Furthermore, a staggered row arrangement of the sensing array was proposed so as to significantly reduce the error due to the sampling step resulting from the pickup coils geometry (from 35% to less than 9% in the worst case). The experimental evaluation of the probe provides promising prospects for the accurate characterization of defects, by means of advanced multifrequency signal processing algorithms.

Three-dimensional ghost imaging LiDAR via sparsity constraint (3D GISC LiDAR), as a staring imaging method, can obtain both the range information and spatial distribution of a remote target with a single-pixel time-resolved detector. However, previous demonstrations mainly focused on the relatively static scene in visible light. Here we propose an airborne near infrared 3D GISC LiDAR system and airborne high-resolution imaging is implemented. Experimental results show that an image with 0.48 m horizontal resolution as well as 0.5 m range resolution at approximately 1.04 km height can be achieved. Some considerations on the improvement of this LiDAR system are also discussed.

Thenormalized backscattered intensity (NBI) profiles at various locations of human thorax by multiprobe laser reflectometer are obtained. These data after digitization, interpolation, and filtering are color-coded and displayed as images on the outline of the human thorax. For optical characterization of tissues in terms of their parameters, scattering and absorption coefficients and the anisotropy parameter (g) are obtained by matching the measured NBI profile with that as obtained by Monte Carlo simulation procedure. Corresponding to the variation of the NBI over the various regions, the optical parameters show their respective changes. The maximum absorption and minimum scattering coef- ficients are observed at the areola, clavicle, sternum, scapula, and vertebral column. The minimum absorption and maximum scattering coefficients are observed at the pectoralis major of chest and rectus abdominis of abdomen regions, as compared to the other regions, attributed to their tissue compositional variations. To visualize the various tissues in lower regions of the thorax, the color-coded scheme of the NBI variation, as measured by the third fiber, is further expanded. By this procedure, the outlines of the heart and lungs, as detected through intercostals regions, are observed, which is in good agreement with that as determined by the chest radiograph of the same subject taken in PA position. Similarly the lower sections of the liver and stomach, due to their distinct optical parameters, are also observed. � 2006 IEEE.

Poly(styrene sulfonic acid) (PSSA) content in poly(vinyl alcohol) (PVA) and PSSA blend membrane is varied and its effect on proton conductivity is studied at varying relative humidity (RH) values. The maximum proton conductivity is observed for the PVA-PSSA membrane with about 35 wt. % PSSA at all humidity values. At 30% RH value, the conductivity of PVA-PSSA blend membrane is 1.20 � 10-3 S/cm, which is about two orders of magnitude higher than the conductivity value of 2.27 � 10-5 S/cm observed for pristine PVA membrane. Water self-diffusion coefficients and water release kinetics of these materials have been characterized by nuclear magnetic resonance (NMR) imaging technique, which validate the use of this membrane in polymer electrolyte fuel cells (PEFCs). A peak power density of 210 mW/cm2 at a load current-density of 500 mA/cm2 is achieved for the PEFC with the optimized PVA-PSSA membrane as electrolyte compared to a peak power density of only 38 mW/cm2 observed at a load current-density of 80 mA/cm2 for the PEFC with pristine PVA membrane as electrolyte while operating at 75 �C with H2 and O2 feeds to the fuel cell maintained at atmospheric pressure. � 2008 Elsevier B.V. All rights reserved.

The Optical, Spectroscopic, and Infrared Remote Imaging System OSIRIS is the scientific camera system onboard the Rosetta spacecraft (Figure 1). The advanced high performance imaging system will be pivotal for the success of the Rosetta mission. OSIRIS will detect 67P/Churyumov-Gerasimenko from a distance of more than 106 km, characterise the comet shape and volume, its rotational state and find a suitable landing spot for Philae, the Rosetta lander. OSIRIS will observe the nucleus, its activity and surroundings down to a scale of ~2 cm px−1. The observations will begin well before the onset of cometary activity and will extend over months until the comet reaches perihelion. During the rendezvous episode of the Rosetta mission, OSIRIS will provide key information about the nature of cometary nuclei and reveal the physics of cometary activity that leads to the gas and dust coma. OSIRIS comprises a high resolution Narrow Angle Camera (NAC) unit and a Wide Angle Camera (WAC) unit accompanied by three electronics boxes. The NAC is designed to obtain high resolution images of the surface of comet 67P/Churyumov-Gerasimenko through 12 discrete filters over the wavelength range 250–1000 nm at an angular resolution of 18.6 μrad px−1. The WAC is optimised to provide images of the near-nucleus environment in 14 discrete filters at an angular resolution of 101 μrad px−1. The two units use identical shutter, filter wheel, front door, and detector systems. They are operated by a common Data Processing Unit. The OSIRIS instrument has a total mass of 35 kg and is provided by institutes from six European countries. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Sweden (SNSB), and Spain (MEC) is gratefully acknowledged. Substantial support for the development of the Data Processing Unit was provided by the ESA Technical Directorate through the Technical Research Programme. In addition to the formal co-authors of this paper (comprising lead scientists, Co-Is, project managers, and lead engineers ), the project was supported by an enormous number of scientists, engineers, and technicians involved in the day-to-day development of the hardware. These include J. C. Blanc, D. Pouliquen, M. Saisse (France), A. Alvarez, A. L. Arteaga, A. Carretero, M. Fernández, H. Guerrero, P. Gutiérrez, J. L. Lizondo, V. Luengo, J. A. Martín, M. A. Martín, J. Meseguer, J. M. Mi, L. Moreno, J. Navarro, A. Núñez, E. Ragel, D. Rodríguez, G. Rosa, A. Sanchez, J. C. Sanmartín, G. Tonellotto (Spain), W. Boogaerts, W. Engelhardt, K. Eulig, B. Fiethe, A. Fischer, M. Gartner, K. Grabig, K. Kellner, A. Kiihn. W. Kiihn. J. Knollenberg, W. Neumann, J. Nitsch, P. Rüffer, H. Schüddekopf, U. Schiihlc. I. Sebastian, S. Stelzer, U. Strohmeyer, T. Tzscheetzsch, M. Wassermeyer (Germany), B. Johlander (ESTEC), M. Baessato, P. F. Brunello, S. Casotto, F. Don-, M. Lazzarin, E. Marchetti, F. Marzari, P. G. Nicolosi, F. Perón, F. Rampazzi, B. Saggin, G. Tondello, S. Verani, P. Zambolin ' (Italy), J. Lagerros, and B. Davidsson (Sweden). Peerreview

Detailed reconstruction of the spatiotemporal history of embryonic cells is key to understanding tissue formation processes but is often complicated by the large number of cells involved, particularly so in vertebrates. Through a combination of high-resolution time-lapse lineage tracing and antibody staining, we have analyzed the movement of mesencephalic and metencephalic cell populations in the early zebrafish embryo. To facilitate the analysis of our cell tracking data, we have created TracePilot, a software tool that allows interactive manipulation and visualization of tracking data. We demonstrate its utility by showing novel visualizations of cell movement in the developing zebrafish brain. TracePilot (http://www.mpi-cbg.de/tracepilot) is Java-based, available free of charge, and has a program structure that allows the incorporation of additional analysis tools. Developmental Dynamics 235:928 –933, 2006. © 2006 Wiley-Liss, Inc.

Diffusely backscattered signals from the human foot sole tissues of normal subjects (n=5) were obtained by multiprobe laser reflectometry. The colour-coded images were constructed from data on the variation of normalised backscattered intensity (NBI), after interpolation and median filtering. The maximum and minimum NBI values at the arch and heel regions of the foot sole, respectively, were observed. The mean NBI at the arch region was significantly higher compared with that at other regions (p < 0.0001). The images of optical parameters of normal tissues show point-to-point variation, attributed to their compositional changes. The pattern of variation of the NBI of a diabetic subject (glucose level 170 mg dl-1) was associated with highly significant variation at the lateral sides of the fore- and middle-foot compared with that of normal subjects. ? IFMBE: 2005.

Magnetic resonance-electrical impedance tomography (MREIT) algorithms fall into two categories: those utilizing internal current density and those utilizing only one component of measured magnetic flux density. The latter group of algorithms have the advantage that the object does not have to be rotated in the magnetic resonance imaging (MRI) system. A new algorithm which uses only one component of measured magnetic flux density is developed. In this method, the imaging problem is formulated as the solution of a non-linear matrix equation which is solved iteratively to reconstruct resistivity. Numerical simulations are performed to test the algorithm both for noise-free and noisy cases. The uniqueness of the solution is monitored by looking at the singular value behavior of the matrix and it is shown that at least two current injection profiles are necessary. The method is also modified to handle region-of-interest reconstructions. In particular it is shown that, if the image of a certain xy-slice is sought for, then it suffices to measure the z-component of magnetic flux density up to a distance above and below that slice. The method is robust and has good convergence behavior for the simulation phantoms used.

Photoacoustic measurement in an imaging system is a unique method as it uses optical disturbance but observes its effect acoustically. Acoustical observation increases the quality of a measurement by reducing the scattering effect that often occurs in optical research. However, a few problems, such as cost and complexity, hinder development of a photoacoustic system. This report presents a design of a photoacoustic system using a laser diode and a commercial microphone as the acoustic emission source and sensor, respectively. Analysis of the photoacoustic signal received by the microphone was performed with software-based Fourier transformation, which makes the photoacoustic system simpler and lower in cost. By measuring the amplitude of the signal, the system accurately detects surface micrometer cracks. The report shows that the system is capable of producing a photoacoustic image of an object with micro-cracks on its surface. The results indicate that the photoacoustic imaging system developed in the experiment is a more promising way to generate images of cracks than optical imaging

A terahertz transmission imaging system based on a quantum-cascade laser (QCL), a fast scanning mirror, and a sensitive Ge:Ga detector is demonstrated. In order to reduce artifacts, special care was taken on the optics and the conversion of the measured data into the image. Images with a diameter of approximately 40 mm and a signal-to-noise ratio of up to 28 dB were obtained within 1.1 s. The system was used to record three dimensional images of objects in an ellipsoidal volume with axes of approximately 40 mm by computed tomography within 87 s. In addition to the Ge:Ga detector, a more compact pyroelectric device was also used for detection.

We demonstrate Adaptive optics - Optical Coherence Tomography (OCT) with modal sensorless Adaptive Optics correction with the use of novel Adaptive Lens (AL) applied for in-vivo imaging of mouse retinas. The AL can generate low order aberrations: defocus, astigmatism, coma and spherical aberration that were used in an adaptive search algorithm. Accelerated processing of the OCT data with a Graphic Processing Unit (GPU) permitted real time extraction of image projection total intensity for arbitrarily selected retinal depth plane to be optimized. Wavefront sensorless control is a viable option for imaging biological structures for which AOOCT cannot establish a reliable wavefront that could be corrected by wavefront corrector. Image quality improvements offered by adaptive lens with sensorless AO-OCT was evaluated on in vitro samples followed by mouse retina data acquired in vivo.

© 2013 IEEE. Recent progress in retinal image acquisition techniques, including optical coherence tomography (OCT) and scanning laser ophthalmoscopy (SLO), combined with improved performance of adaptive optics (AO) instrumentation, has resulted in improvement in the quality of in vivo images of cellular structures in the human retina. Here, we present a short review of progress on developing AO-OCT instruments. Despite significant progress in imaging speed and resolution, eye movements present during acquisition of a retinal image with OCT introduce motion artifacts into the image, complicating analysis and registration. This effect is especially pronounced in high-resolution datasets acquired with AO-OCT instruments. Several retinal tracking systems have been introduced to correct retinal motion during data acquisition. We present a method for correcting motion artifacts in AO-OCT volume data after acquisition using simultaneously captured adaptive optics-scanning laser ophthalmoscope (AO-SLO) images. We extract transverse eye motion data from theAO-SLO images, assign a motion adjustment vector to each AO-OCTA-scan, and re-sample from the scattered data back onto a regular grid. The corrected volume data improve the accuracy of quantitative analyses of microscopic structures.

Витебский государственный университет имени П. М. Машерова. Ученые записки УО "ВГУ им. П. М. Машерова" : сборник научных трудов. - Витебск : ВГУ имени П. М. Машерова, 2014. - Т. 18. - С. 143-148. - Бібліягр.: с. 148 (2 назв.)., Мэта дадзенага артыкула – шматаспектна раскрыць вытокі аўтарскага “казачнага” стылю, вызначыць ідэйна-тэматычны вектар згаданых твораў, выявіць сутнасць і функцыянальнае прызначэнне падзейна драматычных эпізодаў з акцэнтам на іх мастацкім псіхалагізме. = The purpose of this work – to reveal the origins of many aspects of the author’s “fairytale” style, define the conceptual and thematic vector of mentioned works, to identify the nature and functionality of the event dramatic episodes with an emphasis on their artistic psychological character.

Мэта дадзенага артыкула – шматаспектна раскрыць вытокі аўтарскага “казачнага” стылю, вызначыць ідэйна-тэматычны вектар згаданых твораў, выявіць сутнасць і функцыянальнае прызначэнне падзейна драматычных эпізодаў з акцэнтам на іх мастацкім псіхалагізме. = The purpose of this work – to reveal the origins of many aspects of the author’s “fairytale” style, define the conceptual and thematic vector of mentioned works, to identify the nature and functionality of the event dramatic episodes with an emphasis on their artistic psychological character.

" spectral-domain analysis is presented for the scattering by perfectly conducting cylindrical objects behind a dielectric wall. The solution is developed with an analytical-numerical technique, based on the cylindrical wave approach. Suitable cylindrical functions and their spectral representations are introduced as basis functions for the scattered fields, to deal with their interaction with the planar interfaces bounding the wall. The numerical solution is given in TE and TM polarizations states, and in both near- and far-field zones. The model yields an accurate computation of direct scattering that can be useful for through-wall-imaging applications. A stack of three different dielectric media is considered in the theoretical model. In the numerical results, the upper medium, where the incident field is generated, is assumed to be filled by air, the central layer represents the wall, and the lower medium, which contains the scatterers, is air filled, too. Also general problems of scattering by buried objects can be simulated, being the cylinders buried in a medium of arbitrary permittivity, placed below a dielectric layer."

A high-speed (100 kHz A-scans/s) complex conjugate resolved 1 μ swept source optical coherence tomography (SS-OCT) system using coherence revival of the light source is suitable for dense three-dimensional (3-D) imaging of the anterior segment. The short acquisition time helps to minimize the influence of motion artifacts. The extended depth range of the SS-OCT system allows topographic analysis of clinically relevant images of the entire depth of the anterior segment of the eye. Patients with the type 1 Boston Keratoprosthesis (KPro) require evaluation of the full anterior segment depth. Current commercially available OCT systems are not suitable for this application due to limited acquisition speed, resolution, and axial imaging range. Moreover, most commonly used research grade and some clinical OCT systems implement a commercially available SS (Axsun) that offers only 3.7 mm imaging range (in air) in its standard configuration. We describe implementation of a common swept laser with built-in k-clock to allow phase stable imaging in both low range and high range, 3.7 and 11.5 mm in air, respectively, without the need to build an external MZI k-clock. As a result, 3-D morphology of the KPro position with respect to the surrounding tissue could be investigated in vivo both at high resolution and with large depth range to achieve noninvasive and precise evaluation of success of the surgical procedure. © The Authors.

We present a new design for a reflective afocal AO-OCT retinal imaging system. The optical performance of this instrument is compared to our previous multimodal AO-OCT/AO-SLO retinal imaging system. The feasibility of new instrumentation for improved visualization of microscopic retinal structures will be discussed. Examples of images acquired with this new AO-OCT instrument will be presented. © 2013 Copyright SPIE.

Pinned insect specimens stored in museum collections are a fragile and valuable resource for entomological research. As such, they are usually kept away from viewing by the public and hard to access by experts. Here we present a method for mass imaging insect specimens, using GigaPan technology to achieve highly explorable, many-megapixel panoramas of insect museum drawers. We discuss the advantages and limitations of the system, and describe future avenues of collections research using this technology.

We evaluate methods to visualize human retinal micro-circulation in vivo by standard intensity-based optical coherence tomography (OCT), speckle-variance optical coherence tomography (svOCT), and phase-variance optical coherence tomography (pvOCT). En face projection views created from the same volumetric data set of the human retina using all three data processing methods are created and compared. Additionally we used support vector machine (SVM) based semi-automatic segmentation to generate en face projection views of individual retinal layers. The layers include: first, the whole inner retina (from the nerve fiber layer to the outer nuclear layer), and second, from the ganglion cell layer to the outer nuclear layer. Finally, we compare the retinal vasculature images processed from the three OCT techniques and fluorescein angiography (FA). © 2012 SPIE.

We present high-speed Fourier-domain optical coherence tomography (Fd-OCT) with the phase variance based motion contrast method for visualizing retinal micro-circulation in vivo. This technique allows non-invasive visualization of a two-dimensional retinal perfusion map and concurrent volumetric morphology of retinal microvasculature with high sensitivity. The high-speed acquisition rate at 125kHz A-scans enables reduction of motion artifacts with increased scanning area if compared to previously reported results. Several scanning schemes with different sampling densities and scanning areas are evaluated to find optimal parameters for in vivo imaging. In order to evaluate this technique, we compare OCT micro-capillary imaging using the phase variance technique with fundus fluorescein angiography (FA). Additionally, volumetric visualization of blood flow for a normal subject is presented. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Eye movements present during acquisition of a retinal image with optical coherence tomography (OCT) introduce motion artifacts into the image, complicating analysis and registration. This effect is especially pronounced in highresolution data sets acquired with adaptive optics (AO)-OCT instruments. Several retinal tracking systems have been introduced to correct retinal motion during data acquisition. We present a method for correcting motion artifacts in AOOCT volume data after acquisition using simultaneously captured adaptive optics-scanning laser ophthalmoscope (AOSLO) images. We extract transverse eye motion data from the AO-SLO images, assign a motion adjustment vector to each AO-OCT A-scan, and re-sample from the scattered data back onto a regular grid. The corrected volume data improve the accuracy of quantitative analyses of microscopic structures. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

We describe results of retinal imaging with a novel instrument that combines adaptive optics - Fourier-domain optical coherence tomography (AO-OCT) with an adaptive optics scanning laser ophthalmoscope (AO-SLO). One of the benefits of combining Fd-OCT with SLO includes automatic co-registration between the two imaging modalities and the potential for correcting lateral and transversal eye motion resulting in motion artifact-free volumetric retinal imaging. Additionally this allows for direct comparison between retinal structures that can be imaged with both modalities (e.g., photoreceptor mosaics or microvasculature maps). This dual imaging modality could provide insight into some retinal properties that could not be accessed by a single imaging system. Additionally, extension of OCT and SLO beyond structural imaging may open new avenues for diagnostics and testing in ophthalmology. In particular, non-invasive vasculature mapping with these modalities holds promise of replacing fluorescein angiography in vascular identification. Several new improvements of our system are described, including results of testing a novel 97-actuator deformable mirror and AO-SLO light intensity modulation. © 2010 SPIE.

Liquid crystal displays (LCDs) are widely used as spatial light modulators (SLMs) in many applications (optical signal processing, holographic data storage, diffractive optics...). In particular, as an alternative microoptics recording scheme we have explored the possibility to use a LCD to display the diffractive optical element (DOE) to be recorded onto a photosensitive phase material, so as to enhance the flexibility of the recording architecture. In this application the LCD acts as an amplitude dynamic transparency. By means of an optical system we image the function addressed to the LCD onto the recording material. The element to be recorded onto the phase material can be easily changed simply by changing the function addressed to the LCD. Among the recording materials, photopolymers provide very attractive capabilities. They present a great flexibility in their composition, the recording layer can be manufactured in a wide range of possible thicknesses, and they are inexpensive. These properties make it an interesting material to generate the phase DOEs. Both the composition and the thickness need to be optimized for the application to DOEs. In this work we explore the results dealing with the calibration of the recording setup and the photopolymer material. We also analyse the performance of phase-only diffractive lenses generated onto the photopolymer. Promising results have been obtained, where the focalization of the diffractive lenses generated has been demonstrated. This work was supported by “Ministerio de Ciencia e Innovación”, Spain, under projects FIS2008-05856-C02-01 and FIS2008-05856-C02-02), and by the “Generalitat Valenciana”, Spain (projects ACOMP/2009/150, ACOMP/2009/160 and GVPRE/2008/137).