Electronic Camera Research Articles

A NECTAr-based upgrade for the Cherenkov cameras of the H.E.S.S. 12-meter telescopes

The High Energy Stereoscopic System (H.E.S.S.) is one of the three arrays of imaging atmospheric Cherenkov telescopes (IACTs) currently in operation. It is composed of four 12-meter telescopes and a 28-meter one, and is sensitive to gamma rays in the energy range ~ 30 GeV – 100 TeV. The cameras of the 12-m telescopes recently underwent a substantial upgrade, with the goal of improving their performance and robustness. The upgrade involved replacing all camera components except for the photomultiplier tubes (PMTs). This meant developing new hardware for the trigger, readout, power, cooling and mechanical systems, and new software for camera control and data acquisition. Several novel technologies were employed in the cameras: the readout is built around the new NECTAr digitizer chip, developed for the next generation of IACTs; the camera electronics is fully controlled and read out via Ethernet using a combination of FPGA and embedded ARM computers; the software uses modern libraries such as Apache Thrift, ØMQ and Protocol buffers. This work describes in detail the design and the performance of the upgraded cameras.

Analysis of the effects of lead-vehicles on drivers approaching deceleration lanes on a dual carriageway road

The presence of other vehicles interferes with the recognition of the key features of the road environment and induces drivers to concentrate their attention on the moving source of information, reducing the attention towards the fixed elements of the road. In presence of lead-vehicles, drivers focus first on the moving objects and unconsciously slow the search of information for guidance and control. The stimulus-driven attention tends to prevail on the goal-directed attention (Kock, 2004) and the space perception is altered. The aim of this study is to understand how the improper lookout caused by the presence of moving objects like lead-vehicles affects the manoeuvres of drivers navigating interchanges, in proximity to (unexpected) visual elements of the road platform as deceleration lanes. In order to measure the effects of the moving vehicles in the visual scene, a group of twelve drivers preformed driving tests under different conditions in correspondence to the exit lanes of two different interchanges located on a dual carriageway rural road. Their performances were tracked, recorded and analysed by electronic devices and digital cameras installed on the test-car. The results illustrate the drivers’ reaction in presence of lead vehicles located in the centre of their visual field and show how the diverging manoeuvres and the perception of the road environment are influenced.

Image Restoration Model using Total Variance, Bilateral and Wavelet Denoising Filter

iNoise in images are most common due to various degradation. Noises in images are random variations in images due to lighting conditions, camera electronics, surface reflectance, lens, atmospheric conditions and motions (Either camera is moving or object is moving). Image Restoration is a process which restores a degraded image into its original image which has been degraded by some degradation model which degraded the image. Images are degraded due to various reasons. The first and foremost reason for image degradation is the fault in the imaging devices during the image acquisition process. The noise is generated in the imaging devices and is propagated to the image. The second source of degradation in image is the noise added during the image transmission. This type of image degradation is most common. The third source of image degradation is due to the motion blur and atmospheric turbulence. This paper analyzes various image noise models and restoration techniques. Particularly in analyses three kind of filters namely total variance filter, bilateral filter and wavelet image denoising. The image restoration is measured using the PSNR and SSI of original and degraded images

The software and hardware architecture of the real-time protection of in-vessel components in JET-ILW

For the first time, the JET operation in deuterium–tritium (D–T) plasma, which is scheduled to take place on JET in 2020, will be performed in the ITER mix of plasma-facing component materials. In view of the preparation of the DT campaign (DTE2), several aspects of the plasma operation require significant improvements, such as a real-time protection of the first wall. The risk of damaging the metallic PFCs caused by beryllium melting or cracking of tungsten owing to thermal fatigue required a new reliable D–T compatible active protection system. Therefore, the future development of the JET real time first wall protection is focused on the D–T campaign and the ITER relevant conditions which may cause failure of camera electronics within the Torus hall. In addition to the technological aspect, the intensive preparation of the diverse software tools and real time algorithms for hot spot detection as well as alarm handling strategy required for the wall protection is in progress.This contribution describes the improved design, implementation, and operation of the near infrared (NIR) imaging diagnostic system of the JET-ILW plasma experiment and its integration into the existing JET protection architecture. To provide the reliable wall protection during the DTE2, two more sensitive logarithmic NIR camera systems equipped with new optical relays to take images and cameras outside of the biological shield have been installed on JET-ILW and calibrated with an in-vessel calibration light source (ICLS). Additionally, post-pulse data visualization and advanced analysis of all types of imaging data is provided by the new software framework JUVIL (JET users video imaging library). The formation of hot spots is recognized as a significant threat due to rapid surface temperature rise. Because it could trigger the protection system to stop a pulse, it is important to identify the mechanisms and conditions responsible for the formation of such hot spots. To address this issue the new software tool ‘Hotspot Editor’ has been developed.

Towards Infrared Electronic Eyes: Flexible Colloidal Quantum Dot Photovoltaic Detectors Enhanced by Resonant Cavity

Electronic eye cameras are receiving increasing interest due to their unique advantages such as wide field of view, low aberrations, and simple imaging optics compared to conventional planar focal plane arrays. However, the spectral sensing ranges of most electronic eyes are confined to the visible, which is limited by the energy gaps of the sensing materials and by fabrication obstacles. Here, a potential route leading to infrared electronic eyes is demonstrated by exploring flexible colloidal quantum dot (CQD) photovoltaic detectors. Benefitting from their tunable optical response and the ease of fabrication as solution processable materials, mercury telluride (HgTe) CQD detectors with mechanical flexibility, wide spectral sensing range, fast response, and high detectivity are demonstrated. A strategy is provided to further enhance the light absorption in flexible detectors by integrating a Fabry-Perot resonant cavity. Integrated short-wave IR detectors on flexible substrates have peak D* of 7.5 × 1010 Jones at 2.2 µm at room temperature and promise the development of infrared electronic eyes with high-resolution imaging capability. Finally, infrared images are captured with the flexible CQD detectors at varying bending conditions, showing a practical approach to sensitive infrared electronic eyes beyond the visible range.

High Sensitive Night-time Light Imaging Camera Design and In-orbit Test of Luojia1-01 Satellite.

Luojia1-01 satellite is the first scientific experimental satellite applied for night-time light remote sensing data acquisition, and the payload is an optical camera with high sensitivity, high radiation measurement accuracy and stable elements of interior orientation. At the same time, a special shaped hood is designed, which significantly improved the ability of the camera to suppress stray light. Camera electronics adopts the integrated design of focal plane and imaging processing, which greatly reduces the volume and weight of the system. In this paper, the design of the optical camera is summarized, and the results of in-orbit imaging performance tests are analyzed. The results show that the dynamic modulation transfer function (MTF) of the camera is better than 0.17, and the SNR is better than 35 dB under the condition of 10 lx illuminance and 0.3 reflectivity and all indicators meet the design requirements. The data obtained have been widely applied in many fields such as the process of urbanization, light pollution analysis, marine fisheries detection and military.

Structure Retrieval at Atomic Resolution in the Presence of Multiple Scattering of the Electron Probe.

The projected electrostatic potential of a thick crystal is reconstructed at atomic resolution from experimental scanning transmission electron microscopy data recorded using a new generation fast-readout electron camera. This practical and deterministic inversion of the equations encapsulating multiple scattering that were written down by Bethe in 1928 removes the restriction of established methods to ultrathin (≲50 Å) samples. Instruments already coming on line can overcome the remaining resolution-limiting effects in this method due to finite probe-forming aperture size, spatial incoherence, and residual lens aberrations.

Design and Implementation of 3U CubeSat Platform Architecture

This paper describes the main concept and development of a standard platform architecture of 3U Cube Satellite, whose design and performance were implemented and verified through the development of KAUSAT-5 3U CubeSat. The 3U standard platform is built in 1.5U size and developed as a modular concept to add and expand payloads and attitude control actuators to meet the user’s needs. In the case of the electrical power system, the solar panel, the battery, and the deployment mechanism are designed to be configured by the user. Mechanical system design maximizes the electrical capability to accommodate various payloads and to integrate and miniaturize EEE (Electrical, Electronic, and Electromechanical) parts and subsystem functions/performance into limited-size PCBs. The performance of KAUSAT-5 adopting standard platform was verified by mounting the VSCMG (Variable Speed Control Moment Gyro), which is one payload for technical demonstration, at the bottom of the platform and the infrared (IR) camera, which is the other payload for science mission, on the top. The 3U CubeSat equipped with the electronic optical camera is under development implementing the standard platform to reduce development cost and schedule by minimizing additional verification.

A low-cost and efficient cloud monitoring camera system design for imaging satellites

ABSTRACTDesign and development of a cloud monitoring camera (CMC) as a secondary camera for imaging/remote-sensing satellites is proposed here. It is well known that presence of clouds alters the earth-atmospheree energy budget by scattering and absorbing the shortwave radiation and absorbing and re-emitting the infrared radiation. Detection of clouds at precise positions, prior to the initiation of the imaging session of the primary (super resolution) camera can aid in saving power as well as memory storage of the satellite. Key feature of the proposed system is the implementation of an onboard cloud detection system in the visible band. The proposed system is miniature in size and cost-effective when compared to the existing integrated visible and infrared band detection system. It primarily consists of lens assembly, detector head assembly, field programmable gate array (FPGA)-based camera electronics system with supporting proximity electronics. Cloud detection algorithm for the visible band images is derived and simulated with the help of Laboratory Virtual Instrument Engineering Workbench software. The verification and hardware realization of the algorithm is achieved by implementing it on a FPGA-based system. Overall simulated and measured efficiency of more than 94% was achieved. The volume of the system is 85 mm × 85 mm × 25 mm and weighs approximately 2 kg, making it suitable for satellite mounting.

UAV application for precision agriculture

PurposeThe purpose of this study is to show the potentials of a cost-effective unmanned aerial vehicles (UAV) system for agriculture industry. The current population growth rate is so vast that farming industry must be highly efficient and optimized. As a response for high quality food demands, the new branch of the agriculture industry has been formed – the precision agriculture. It supports farming process with sensors, automation and innovative technologies. The UAV advantages over regular aviation are withering. Not only they can fly at lower altitude and are more precise but also offer same high quality and are much cheaper.Design/methodology/approachThe main objective of this project was to implement an exemplary cost-effective UAV system with electronic camera stabilizer for gaining useful data for agriculture. The system was based on small, unmanned flying wing able to perform fully autonomous missions, a commercially available camera and an own-design camera stabilizer. The research plan was to integrate the platform and run numerous experimental flights over farms, fields and woods collecting aerial pictures. All the missions have been planned to serve for local farming and forest industries and cooperated with local business authorities.FindingsIn preliminary flight tests, the variety of geodetic, forest and agriculture data have been acquired, placed for post processing and applied for the farming processes. The results of the research were high quality orthophoto maps, 3D maps, digital surface models and images mosaics with normalized difference vegetation index. The end users were astonished with the high-quality results and claimed the high importance for their business.Originality/valueThe case study results proved that this kind of a small UAV system is exceptional to manage and optimize processes at innovative farms. So far only professional, high-cost UAV platforms or traditional airships have been applied for agriculture industry. This paper shows that even simple, commercially available equipment could be used for professional applications.

Analysis of prediction methods applied to a selected road vehicle tracing system

The system which is developed in Department of Transport and Electrical Engineering UTH Rad. consists of collecting, analyzing and selecting data from existing observation units, and such to be installed in the future, including photo-radars, electronic fee collection and traffic monitoring cameras. The aim is tracking of objects distinguished by certain visual features. The present paper specifies the road net on chosen area and further, algorithms for the prediction of the continuations of vehi-cle tracks registered by the system are on consideration and assessed.

Dynamics of Transformation from Platinum Icosahedral Nanoparticles to Larger FCC Crystal at Millisecond Time Resolution

Atomic motion at grain boundaries is essential to microstructure development, growth and stability of catalysts and other nanostructured materials. However, boundary atomic motion is often too fast to observe in a conventional transmission electron microscope (TEM) and too slow for ultrafast electron microscopy. Here, we report on the entire transformation process of strained Pt icosahedral nanoparticles (ICNPs) into larger FCC crystals, captured at 2.5 ms time resolution using a fast electron camera. Results show slow diffusive dislocation motion at nm/s inside ICNPs and fast surface transformation at μm/s. By characterizing nanoparticle strain, we show that the fast transformation is driven by inhomogeneous surface stress. And interaction with pre-existing defects led to the slowdown of the transformation front inside the nanoparticles. Particle coalescence, assisted by oxygen-induced surface migration at T ≥ 300 °C, also played a critical role. Thus by studying transformation in the Pt ICNPs at high time and spatial resolution, we obtain critical insights into the transformation mechanisms in strained Pt nanoparticles.

Experimental Study of Combustion Characteristics of Circular Ring Thin-Layer Pool Fire

For clarifying the combustion behavior of circular ring thin-layer pool fire, a series of experiments with varying pool diameters were carried out. The equivalent pool area of 0.071 m^2 and an initial n-heptane thickness of 10 mm were fixed. Electronic balance, digital camera and K-type thermocouples were used respectively to measure burning rate, flame height as well as centerline temperature. The results show that more burning stages can appear with the increase of the inner and outer diameters of circular ring pool. Fire merging can occur at any one of initial growth, quasi-steady burning with surface boiling, transition to bulk boiling and bulk boiling burning stages, and moreover the maximum burning rate of fire merging is about 3.5 times the one of the ordinary pool fire with same area. The core hollow region plays an important effect in decreasing the burning rate, flame height and fire merging time etc. The evolutions of the characteristic parameters e.g. burning rate, flame height and centerline ...

Reverse logistics network design: a case of mobile phones and digital cameras

The world is producing electrical and electronic waste (e-waste) more than ever before. According to a UN study, between 2009 and 2014, the global annual production of electronic waste has been approximately fixed at 42 million tonnes. The improper and unscientific disposal of e-waste is a big threat to the environment. The purpose of this paper is to develop a mathematical model for the network design of a multi-product, multi-echelon reverse logistics system. Different recovery options such as remanufacturing, repairing and recycling are considered in this study. Based on the residual value of the used product, the returns are graded into two categories—low product residual value (PRV) and high PRV returns. Although the process of grading results in additional grading costs, it assists the decision maker in choosing appropriate recovery option. An integer linear programming formulation is used to model and solve the problem. Two commonly used consumer electronic goods, mobile phones and digital cameras, are considered for validation. The proposed model determines the optimal number and location of different facilities to be established. By way of explicit consideration of the product structure, the analysis is carried out down to the level of components across the different stages of the supply chain. Further, detailed analysis is performed to determine minimum quantities of high PRV returns for a remanufacturing facility to be economically viable. The results provide interesting information about the relevance of quantum of products with high PRV on the network design decisions. Also, the results underscore the importance of transportation costs on the overall profitability of the reverse supply chain.

Elimination of resampling errors in wide area motion imagery (WAMI)

Extraction of useful information from Wide Area Motion Imagery (WAMI) data is limited by the resolution and clarity of the image. The resolution of the raw image is defined by the camera, optics, and conversion electronics. For use by an analyst, the raw image must be converted to a geo-rectified image. This projection process requires resampling, which results in a loss of resolution. In addition, compression may be required to accommodate a limited band width transmission link or limited storage space, again with a loss of resolution. Resampling and compression can reduce the clarity of the image as seen by the analyst. In this article, the impact of resampling and compression for the Wright Patterson Air Force Base (WPAFB) 20091021 data set are analyzed. This data set contains both raw images and projected images. The projected images are generated using the traditional sensor exploitation tool (SET) model. The raw images are then projected using the SET model developed here. The resolution of the traditional SET and the proposed SET are measured. Measurement of the compression loss shows that compression is not responsible for the loss of resolution. The resolution is limited by the resampling process. To eliminate resampling errors, a novel SET model is proposed. The proposed SET model preserves the resolution of the original raw image by eliminating the resampling process before data storage and transmission.

The Aesthetics of Astrophysics: How to Make Appealing Color-composite Images that Convey the Science

Astronomy has a rich tradition of using color photography and imaging, for visualization in research as well as for sharing scientific discoveries in formal and informal education settings (i.e., for “public outreach”). In the modern era, astronomical research has benefitted tremendously from electronic cameras that allow data and images to be generated and analyzed in a purely digital form with a level of precision that previously was not possible. Advances in image-processing software have also enabled color-composite images to be made in ways that are much more complex than with darkroom techniques, not only at optical wavelengths but across the electromagnetic spectrum. The Internet has made it possible to rapidly disseminate these images to eager audiences. Alongside these technological advances, there have been gains in understanding how to make images that are scientifically illustrative as well as aesthetically pleasing. Studies have also given insights on how the public interprets astronomical images and how that can be different than professional astronomers. An understanding of these differences will help in the creation of images that are meaningful to both groups. In this invited review, we discuss the techniques behind making color-composite images as well as examine the factors one should consider when doing so, whether for data visualization or public consumption. We also provide a brief history of astronomical imaging with a focus on the origins of the “modern era” during which distribution of high-quality astronomical images to the public is a part of nearly every professional observatory’s public outreach. We review relevant research into the expectations and misconceptions that often affect the public’s interpretation of these images.

The upgrade of the H.E.S.S. cameras

The High Energy Stereoscopic System (HESS) is an array of imaging atmospheric Cherenkov telescopes (IACTs) located in the Khomas highland in Namibia. It was built to detect Very High Energy (VHE >100GeV) cosmic gamma rays. Since 2003, HESS has discovered the majority of the known astrophysical VHE gamma-ray sources, opening a new observational window on the extreme non-thermal processes at work in our universe. HESS consists of four 12-m diameter Cherenkov telescopes (CT1–4), which started data taking in 2002, and a larger 28-m telescope (CT5), built in 2012, which lowers the energy threshold of the array to 30GeV. The cameras of CT1–4 are currently undergoing an extensive upgrade, with the goals of reducing their failure rate, reducing their readout dead time and improving the overall performance of the array. The entire camera electronics has been renewed from ground-up, as well as the power, ventilation and pneumatics systems, and the control and data acquisition software. Only the PMTs and their HV supplies have been kept from the original cameras. Novel technical solutions have been introduced, which will find their way into some of the Cherenkov cameras foreseen for the next-generation Cherenkov Telescope Array (CTA) observatory. In particular, the camera readout system is the first large-scale system based on the analog memory chip NECTAr, which was designed for CTA cameras. The camera control subsystems and the control software framework also pursue an innovative design, exploiting cutting-edge hardware and software solutions which excel in performance, robustness and flexibility. The CT1 camera has been upgraded in July 2015 and is currently taking data; CT2-4 have been upgraded in fall 2016. Together they will assure continuous operation of HESS at its full sensitivity until and possibly beyond the advent of CTA. This contribution describes the design, the testing and the in-lab and on-site performance of all components of the newly upgraded HESS camera.

A New Expander Mechanism of an Infrared Laser Based on Different Nanometre Quantum Dot Particles

A New Expander Mechanism of an Infrared Laser Based on Different Nanometre Quantum Dot Particles The traditional beam expander mechanism is derived from the Galilean and Kepler telescopes and the glass prism, which have been used for hundreds of years. Our experiments reveal that two different ITO quantum dots and NaYF4:Yb, Er nanometre particles mixed uniformly can be used to realize a Laser beam expander. The expander can be detected only by a CCD electronic camera. The expander of the infrared laser does not depend on a prism; it is a novel quantum mechanism. The mixed nanometre powder 0.2-1 mm-thickness wafer can expand the laser light spot by 2-4 times. Although the expanded laser light energy strength clearly decreases, it can still be detected well by the CCD camera. The new mechanism supplies a new possibility for improving infrared laser range radar finders, positioning, 3D processing and laser disc information storage.

Resonance Energy Transfer-Based Nucleic Acid Hybridization Assays on Paper-Based Platforms Using Emissive Nanoparticles as Donors.

Quantum dots (QDs) and upconverting nanoparticles (UCNPs) are luminescent nanoparticles (NPs) commonly used in bioassays and biosensors as resonance energy transfer (RET) donors. The narrow and tunable emissions of both QDs and UCNPs make them versatile RET donors that can be paired with a wide range of acceptors. Ratiometric signal processing that compares donor and acceptor emission in RET-based transduction offers improved precision, as it accounts for fluctuations in the absolute photoluminescence (PL) intensities of the donor and acceptor that can result from experimental and instrumental variations. Immobilizing NPs on a solid support avoids problems such as those that can arise with their aggregation in solution, and allows for facile layer-by-layer assembly of the interfacial chemistry. Paper is an attractive solid support for the development of point-of-care diagnostic assays given its ubiquity, low-cost, and intrinsic fluid transport by capillary action. Integration of nanomaterials with paper-based analytical devices (PADs) provides avenues to augment the analytical performance of PADs, given the unique optoelectronic properties of nanomaterials. Herein, we describe methodology for the development of PADs using QDs and UCNPs as RET donors for optical transduction of nucleic acid hybridization. Immobilization of green-emitting QDs (gQDs) on imidazole functionalized cellulose paper is described for use as RET donors with Cy3 molecular dye as acceptors for the detection of SMN1 gene fragment. We also describe the covalent immobilization of blue-emitting UCNPs on aldehyde modified cellulose paper for use as RET donors with orange-emitting QDs (oQDs) as acceptors for the detection of HPRT1 gene fragment. The data described herein is acquired using an epifluorescence microscope, and can also be collected using technology such as a typical electronic camera.

A Major Upgrade of the H.E.S.S. Cherenkov Cameras

The High Energy Stereoscopic System (H.E.S.S.) is an array of imaging atmospheric Cherenkov telescopes (IACTs) located in Namibia. It was built to detect Very High Energy (VHE, >100 GeV) cosmic gamma rays, and consists of four 12 m diameter Cherenkov telescopes (CT1-4), built in 2003, and a larger 28 m telescope (CT5), built in 2012. The larger mirror surface of CT5 permits to lower the energy threshold of the array down to 30 GeV. The cameras of CT1-4 are currently undergoing an extensive upgrade, with the goals of reducing their failure rate, reducing their readout dead time and improving the overall performance of the array. The entire camera electronics has been renewed from ground-up, as well as the power, ventilation and pneumatics systems, and the control and data acquisition software. Technical solutions forseen for the next-generation Cherenkov Telescope Array (CTA) observatory have been introduced, most notably the readout is based on the NECTAr analog memory chip. The camera control subsystems and the control software framework also pursue an innovative design, increasing the camera performance, robustness and flexibility. The CT1 camera has been upgraded in July 2015 and is currently taking data; CT2-4 will upgraded in Fall 2016. Together they will assure continuous operation of H.E.S.S at its full sensitivity until and possibly beyond the advent of CTA. This contribution describes the design, the testing and the in-lab and on-site performance of all components of the newly upgraded H.E.S.S. camera.