Concept Of Camera Research Articles

Development of a compact bolometer camera concept for investigation of radiation asymmetries at Wendelstein 7-X.

Power exhaust is one of the central challenges in magnetically confined fusion plasmas. Radiative detachment can be employed to reduce particle and heat fluxes to the divertor target, mitigating divertor damage and erosion. However, accomplishing this for a non-axisymmetric machine such as Wendelstein 7-X is a non-trivial task because of the complex role of transport and plasma-wall interaction in a three-dimensional magnetic field topology. We introduce a new bolometer camera design that can be easily installed in multiple toroidal locations and adapted to the required geometry, providing additional spatial coverage. This can be used to locally enhance tomographic capabilities or to resolve spatial variations of the plasma emissivity. By including these non-uniformities in the total radiated power estimate, global power balance measurements can be improved. We model each bolometer camera using ray tracing. We then analyze the forward-modeled detector response to several physically motivated synthetic emission phantoms with respect to its capability to quantify the local average emissivity. The results prove this concept as a promising asset for the investigation of poloidal and toroidal radiated power asymmetries in Wendelstein 7-X. The first CBC prototypes have undergone development and installation for the next experimental campaign.

Single-layer Compton camera based on a 1 mm thick pixelated CDTE detectors

Compton camera is a novel γ-camera paradigm that relies upon the kinematics of Compton scattering for image reconstruction. A Conventional Compton camera uses two layers of sensors - the Absorber and the Scatterer. This work reports the proof of concept of a single-layer Compton camera (SLCC) where simultaneous Compton pairs events are registered in a single High-Z semiconductor sensor. The Hybrid pixel detector (HPD) is 1 mm thick, 256 x 256 square pixels with 55 μm pixel pitch CdTe sensor bonded to a Timepix3 readout ASIC. The superior spectroscopic imaging and fast timing capabilities of the Timepix3 readout ASIC coupled with a microscopic and highly pixelated CdTe enable simultaneous event detection of multi-energies occurring at multiple positions. The concept was exemplified by measuring the 122 KeV γ-ray emitted from a 57Co radioisotope source at two positions. Data were captured in the Timepix3 data-driven mode with the KATHERINE readout system via Gigabyte Ethernet data transfer. A bespoke Compton kinematics criterion algorithm implemented in Python 3 IDE was used for data analysis and Compton’s image reconstruction. Numerous events (5.2 million) were captured for 30-minute acquisitions. However, due to the thin nature of CdTe, fewer events (≈ 0.01 %) met the Compton event selection criteria. Nevertheless, the algorithm accurately pinpointed the radioisotope’s location, demonstrating proof of concept of the SLCC system.

An innovative sCMOS based autonomous astronomical camera dedicated to universal use for SST and other fields of optical astronomy

Creotech Instruments is advancing a game-changing sCMOS camera series. The Final Prototype Model of an astronomical camera for Space Surveillance and Tracking (SST) is in the test campaign phase. Designed for SST, NEO, and debris detection, its adaptable platform suits quantum tech and biological microscopy. Edge computing sets it apart, leveraging FPGA-based SoC for real-time processing and Linux-based pre-processing. Operating autonomously, it supports on-camera ML algorithms, revolutionizing astronomy. Data pre-processing, like frame stacking, reduces data load. This paper introduces the camera's concept, architecture, and prototype test results, emphasizing specific use cases and future product line development.

Single-shot synthetic wavelength imaging: Sub-mm precision ToF sensing with conventional CMOS sensors

We present a novel single-shot interferometric ToF camera targeted for precise 3D measurements of dynamic objects. The camera concept is based on Synthetic Wavelength Interferometry, a technique that allows retrieval of depth maps of objects with optically rough surfaces at submillimeter depth precision. In contrast to conventional ToF cameras, our device uses only off-the-shelf CCD/CMOS detectors and works at their native chip resolution (as of today, theoretically up to 20 Mp and beyond). Moreover, we can obtain a full 3D model of the object in single-shot, meaning that no temporal sequence of exposures or temporal illumination modulation (such as amplitude or frequency modulation) is necessary, which makes our camera robust against object motion.In this paper, we introduce the novel camera concept and show the first measurements that demonstrate the capabilities of our system. We present 3D measurements of small (cm-sized) objects with > 2 Mp point cloud resolution (the native pixel resolution of our used detector) and up to sub-mm depth precision. We also report a “single-shot 3D video” acquisition and a first single-shot “Non-Line-of-Sight” measurement. Our technique has great potential for high-precision applications with dynamic object movement, e.g., in AR/VR, industrial inspection, medical imaging, and imaging through scattering media like fog or human tissue.

Compact snapshot hyperspectral camera for ophthalmology

Hyperspectral imaging is an emerging technique that allows measurement of spectral absorption at each point of a scene, thus offering the capability to identify and characterize important biomarkers for clinical practice and therapeutic research, as well as enhancing image identification of important structures. So far, few hyperspectral cameras have been used for retinal scanning because of the need to acquire the image in a fraction of a second. Here, and to the best of our knowledge, we present a novel concept of a snapshot hyperspectral camera suited for retinal imaging. We demonstrate the technique by presenting the optical density spectrum of a healthy patient’s retina in the 450–700 nm range, together with the spectral response of several retinal features.

Payload Camera Breadboard for Space Surveillance—Part I: Breadboard Design and Implementation

The rapid increase of space debris poses a risk to space activities, so it is vital to develop countermeasures in terms of space surveillance to prevent possible threats. The current Space Surveillance Network is majorly composed of radar and optical telescopes that regularly observe and track space objects. However, these measures are limited by size, being able to detect only a tiny amount of debris. Hence, alternative solutions are essential for securing the future of space activities. Therefore, this paper proposes the design of a payload camera breadboard for space surveillance to increase the information on debris, particularly for the under-catalogued ones. The device was designed with similar characteristics to star trackers of small satellites and CubeSats. Star trackers are attitude devices usually used in satellites for attitude determination and, therefore, have a wide potential role as a major tool for space debris detection. The breadboard was built with commercial off-the-shelf components, representing the current space-camera resolution and field of view. The image sensor was characterized to compute the sensitivity of the camera and evaluate the detectability performance in several simulated positions. Furthermore, the payload camera concept was tested by taking images of the night sky using satellites as proxies of space debris, and a photometric analysis was performed to validate the simulated detectability performance.

Robust Vision-Based Sliding Mode Control for Uncooperative Ground Target Searching and Tracking by Quadrotor

In this paper, the problem of searching and tracking uncooperative and unidentified mobile ground target using a quadcopter unmanned aerial vehicle (QUAV) is investigated. The proposed strategy is an Image-Based Visual Servoing (IBVS) approach, combined with the virtual camera concept and robust control. This strategy makes use of the rough prior information of the target, in contrast with existing strategies, which will alleviate the problem of altitude estimation noise and enhance the overall accuracy. Hence, a new vision-based sliding mode controller (SMC) is designed to control the quadcopter taking into account the flight phase’s heterogeneity, the external disturbances and parameters uncertainties as well as the target maneuverability. In order to get a better insight about the SMC tuning and adjustment, three different reaching laws are evaluated and compared. The proposed controller allows an automatic execution of the flight strategy whilst the searching phase relies on the Camera Coverage Area (CCA) technique. The vision-based technique allows an automatic QUAV altitude tuning for optimal target observation and tracking. Another contribution of this work is the fact that the designed controller validity and stability overspan the entire scenario to reach the universal and to smoothen out surges generated by control switching. Numerical simulations are conducted to compare the proposed SMC controllers and validate the effectiveness of the whole strategy.

A high-resolution neutron spectroscopic camera for the SPARC tokamak based on the Jet European Torus deuterium-tritium experience.

Dedicated nuclear diagnostics have been designed, developed, and built within EUROFUSION enhancement programs in the last ten years for installation at the Joint European Torus and capable of operation in high power Deuterium-Tritium (DT) plasmas. The recent DT Experiment campaign, called DTE2, has been successfully carried out in the second half of 2021 and provides a unique opportunity to evaluate the performance of the new nuclear diagnostics and for an understanding of their behavior in the record high 14MeV neutron yields (up to 4.7 × 1018 n/s) and total number of neutrons (up to 2 × 1019n) achieved on a tokamak. In this work, we will focus on the 14MeV high resolution neutron spectrometers based on artificial diamonds which, for the first time, have extensively been used to measure 14MeV DT neutron spectra with unprecedented energy resolution (Full Width at Half Maximum of ≈1% at 14 MeV). The work will describe their long-term stability and operation over the DTE2 campaign as well as their performance as neutron spectrometers in terms of achieved energy resolution and high rate capability. This important experience will be used to outline the concept of a spectroscopic neutron camera for the SPARC tokamak. The proposed neutron camera will be the first one to feature the dual capability to measure (i) the 2.5 and 14MeV neutron emissivity profile via the conventional neutron detectors based on liquid or plastics scintillators and (ii) the 14MeV neutron spectral emission via the use of high-resolution diamond-based spectrometers. The new opportunities opened by the spectroscopic neutron camera to measure plasma parameters will be discussed.

Intelligent electromagnetic metasurface camera: system design and experimental results

Abstract Electromagnetic (EM) sensing is uniquely positioned among nondestructive examination options, which enables us to see clearly targets, even when they visually invisible, and thus has found many valuable applications in science, engineering and military. However, it is suffering from increasingly critical challenges from energy consumption, cost, efficiency, portability, etc., with the rapidly growing demands for the high-quality sensing with three-dimensional high-frame-rate schemes. To address these difficulties, we propose the concept of intelligent EM metasurface camera by the synergetic exploitation of inexpensive programmable metasurfaces with modern machine learning techniques, and establish a Bayesian inference framework for it. Such EM camera introduces the intelligence over the entire sensing chain of data acquisition and processing, and exhibits good performance in terms of the image quality and efficiency, even when it is deployed in highly noisy environment. Selected experimental results in real-world settings are provided to demonstrate that the developed EM metasurface camera enables us to see clearly human behaviors behind a 60 cm-thickness reinforced concrete wall with the frame rate in order of tens of Hz. We expect that the presented strategy could have considerable impacts on sensing and beyond, and open up a promising route toward smart community and beyond.

Single-pixel scatter-plate microscopy.

Based on the optical memory effect of scattered light, we developed a new single-pixel camera concept. The retrieved images contain both 3D and spectral information about the sample. A spatial light modulator (SLM) generates a random intensity modulation. The signal recorded by the single-pixel detector is cross correlated by the calculated point spread function (PSF) signals of the SLM to retrieve the image. In this publication, both simulations and experimental results are presented.

Fluorescence lifetime imaging via spatio-temporal speckle patterns in a single-pixel camera configuration.

Photoluminescence (PL) spectroscopy offers excellent methods for mapping the PL decay on the nanosecond time scale. However, capturing maps of emission dynamics on the microsecond timescale can be highly time-consuming. We present a new approach to fluorescence lifetime imaging (FLIM), which combines the concept of random temporal speckles excitation (RATS) with the concept of a single-pixel camera based on spatial speckles. The spatio-temporal speckle pattern makes it possible to map PL dynamics with unmatched simplicity. Moreover, the method can acquire all the data necessary to map PL decay on the microsecond timescale within minutes. We present proof-of-principle measurements for two samples and compare the reconstructed decays to the non-imaging measurements. Finally, we discuss the effect of the preprocessing routine and other factors on the reconstruction noise level. The presented method is suitable for lifetime imaging processes in several samples, including monitoring charge carrier dynamics in perovskites or monitoring solid-state luminophores with a long lifetime of PL.

Politik Kamera: Rumen Yeni Dalga Sinemasında Bakışın İdeolojikleşmesi ve Kadın Bedeninin Temsili | Political Camera: The Ideologization of View in Romanian New Wave Cinema and Representation of Women’s Body

Sinema, toplumsal konuların işlenmeleri sürecinde bir pratikler bütünü şeklinde değerlendirilmekte ve meydana gelen olayların ele alınıp aktarılmasında önemli bir araç olarak kabul edilmektedir. Çeşitli ideolojilerin yeniden üretildiği bir alan olan sinema, ana akım anlatıya karşıt söylemler için de kullanılabilmektedir. Rumen Yeni Dalga sineması, ele aldığı temalar ve kullandığı teknikler bakımından ana akım anlatıya karşıt bir tutum sergilemektedir. Çavuşesku rejiminin kitleler üzerinde oluşturduğu korku, tehdit ve güvensizlik hâlinin Rumen Yeni Dalga sinemasında sıklıkla ele alındığı bilinmekte ve döneme yönelik filmlerde geçmişle hesaplaşma kaygısı taşındığı düşünülmektedir. Buna göre, Çavuşesku rejiminin Romanyalı vatandaşlarda yarattığı travmaya birçok kişi kayıtsız kalmakta ve bu noktada sinema, sesin duyurulması anlamında etkin bir biçimde kullanılmaktadır. Dönemin nitelikleri, soğuk renklerle, plan-sekanslarla, karanlık alanlar gibi biçimsel kodlarla yeniden inşa edilmekte ve böylece gerginliğin izler-kitleye aktarılması gibi yorumun da yine izler-kitleye bırakılması söz konusu olmaktadır. Bu çalışma kapsamında Cristian Mungiu’nun Rumen Yeni Dalga’sının önde gelen yönetmenlerinden biri olmasından hareketle, yönetmenin 4 Luni, 3 Săptămâni şi 2 Zile (4 Ay, 3 Hafta, 2 Gün- 2007) filmi örnek olarak ele alınmakta, ilgili film, eril bakış ve toplumsal cinsiyet kodları temel alınarak analiz edilmektedir. Bakışın eril bir nitelik taşıması ve kadın bedenini izlenebilir kılması, analizin çıkış noktasını oluşturmakta ve Mungiu’nun eril kodları tersine çevirerek dönemin Romanya’sına karşı bir meydan okuma/hesaplaşma kaygısı güttüğü düşünülmektedir. Bu nedenle film analizi, politik kamera kavramından hareketle politik bir okumayı da içermektedir.

An Analysis of Students’ Misconceptions on the Implementation of Active Learning of Optics and Photonics Approach Assisted by Computer Simulation

Misconceptions take place in a variety of Physics lesson subjects including the Light and Optics. This study aimed at determining the students’ misconceptions and the effectiveness of Active Learning of Optics and Photonics (ALOP) approach assisted by computer simulation to reduce misconceptions among students on the material of optical instruments. The mixed method was employed in this study using embedded mixed method design. The study was conducted to students of grade XI in one senior high school in Bandung. The participants were divided into two groups: control group and experimental group in which each group consisted of 23 students. A conventional learning was applied in the con-trol group while the experimental class implemented ALOP computer-aided simulation learning. The instrument used to identify students’ misconceptions were Four-Tier Optics and Photonics Test (FTOPT), consisted of 18 items, which was given during the pre-test and post-test. The results showed that misconceptions were disseminated over the concept of eyes, camera, magnifier, mi-croscopes, and telescopes. Additionally, ALOP approach using computer-aided simulations is effective to reduce students’ misconceptions on the material of op-tical instrument.

Single layer Compton camera based on Timepix3 technology

The Compton camera concept is based on reconstruction of recorded Compton scattering events for incoming gamma rays. The camera usually consist of two or more position (2D) and energy sensitive detectors. The Compton scattering of the incoming gamma ray recoiling an electron occurs in the first detector. The position and energy of recoiled electron is recorded. The scattered gamma ray continues to the next detector where it is absorbed and its energy and position is recorded too. Knowing both positions and energies the scattering angle can be calculated using the Compton equation. By detecting multiple events the position and image of the gamma source can be reconstructed. The Compton scattering and absorption of the scattered gamma can occur within a single detector too. Such events can be used for reconstruction only if the detector provides information on 3D positions of both events along with their energies. The Timepix3, a hybrid single photon counting pixel detector, is perfect device for such measurements. It can record time-of-arrival (ToA) and energy of incident gamma rays simultaneously in each pixel. In this article we present a concept of miniaturized single layer Compton camera consisting of a single Timepix3 detector with a thick 2 mm CdTe sensor. Thanks to Timepix3 high resolution ToA measurement (1.6 ns), it is possible to measure the drift time of charge transport within the sensor and thus determine the vertical position (depth) of both interactions. By knowing both energy and position of the events in the sensor, we can reconstruct the image of the gamma source. The angular resolution of the presented Compton camera depends on the detected energy and reaches the order of a few degrees.

Single-pixel camera photoacoustic tomography.

.Since it was first demonstrated more than a decade ago, the single-pixel camera concept has been used in numerous applications in which it is necessary or advantageous to reduce the channel count, cost, or data volume. Here, three-dimensional (3-D), compressed-sensing photoacoustic tomography (PAT) is demonstrated experimentally using a single-pixel camera. A large area collimated laser beam is reflected from a planar Fabry–Pérot ultrasound sensor onto a digital micromirror device, which patterns the light using a scrambled Hadamard basis before it is collected into a single photodetector. In this way, inner products of the Hadamard patterns and the distribution of thickness changes of the FP sensor—induced by the photoacoustic waves—are recorded. The initial distribution of acoustic pressure giving rise to those photoacoustic waves is recovered directly from the measured signals using an accelerated proximal gradient-type algorithm to solve a model-based minimization with total variation regularization. Using this approach, it is shown that 3-D PAT of imaging phantoms can be obtained with compression rates as low as 10%. Compressed sensing approaches to photoacoustic imaging, such as this, have the potential to reduce the data acquisition time as well as the volume of data it is necessary to acquire, both of which are becoming increasingly important in the drive for faster imaging systems giving higher resolution images with larger fields of view.

INVESTIGATIONS ON THE GEOMETRIC QUALITY OF CAMERAS FOR UAV APPLICATIONS USING THE HIGH PRECISION UAV TEST FIELD ZOLLERN COLLIERY

Abstract. The geodetic-photogrammetric test field at the industrial monument Zollern colliery in Dortmund offers a scenario for carrying out geometric and radiometric tests of UAV systems. The foundation for this builds a geodetic precision network (position and height accuracy approx. 2 mm) with a total of 45 ground control points, distributed over an area of approx. 7 hectares. Within the scope of a campaign carried out in autumn 2017, various UAV sensor systems were tested under comparable conditions. Within this paper geometric investigations of two current DJI cameras, Zenmuse X4S (20 Mpix) and X5S (20.8 Mpix), as well as a Phase One IXU 1000 (100 Mpix) are presented. While the Zenmuse cameras reflect the current state of development of the manufacturer DJI, the medium format camera system from Phase One is primarily settled in the classic aerial segment. However, the desire for increased measurement accuracy (e. g. for engineering applications) also makes such a high-performance sensor interesting for UAV applications.In addition to the configuration of the test field, the system comparison requires identical parameters for flight planning, in particular image overlapping, a complete cross flight configuration at different flight altitudes and the definition of a uniform ground resolution (GSD = 14 mm).The investigations show clear differences in the achievable quality of the cameras. Though the high-priced Phase One system shows the best results, the most cost-effective system, the Zenmuse X4S, delivers only slightly worse results. In contrast, the Zenmuse X5S performs significantly worse than the other systems, mainly resulting from the mechanically unstable camera concept with interchangeable lenses. Finally, the comparison of the software products Pix4D Pix4Dmapper, Inpho UASMaster by Trimble and Agisoft PhotoScan partly shows significant differences in the results of image orientation. In particular in settings with sparse GCP usage the results vary considerably, indicating different strategies on how the residuals are distributed and the datum is defined, mostly Pix4Dmapper outperforms the others. In better GCP configurations there is no significant difference between Pix4mapper and Agisoft PhotoScan, while UASMaster does never deliver the best results.

Compton camera based on Timepix3 technology

The Compton camera concept is based on the reconstruction of recorded Compton scattering events of incoming gamma rays. The scattering of primary gamma ray occurs in the first detector (called scattering detector—usually thin) recording the position and energy of the recoiled electron. The scattered gamma quantum continues towards the second detector (called absorption detector - usually thick) where it is absorbed. The second detector records the energy and the position of this scattered gamma. Using the Compton scattering equation it is possible to determine the scattering angle, and estimate possible directions of the original gamma ray as a surface of a cone. When the Compton camera records the number of such events, the location and the shape of the gamma source can be reconstructed. Timepix3, a hybrid single photon counting imaging pixel detector, is a perfect device for creation of a compact Compton camera. Timepix3 is an event based readout chip (every hit pixel is immediately sent to a readout) and can record the time-of-arrival (ToA) and energy of an incident gamma simultaneously in each pixel. The chip offers high energy resolution (1 keV at 60 keV, 7 keV at 356 keV), as well as time resolution (1.6 ns). The Timepix3 readout chip can be combined with different sensor materials (Si, CdTe, CZT). In this contribution, we present a very compact detector system for imaging with gamma-rays using the Compton camera principle. The system consists of at least two layers of hybrid pixel detectors Timepix3 with the sensors being optimized for gamma-ray tracking. The front detector layer (scattering) is made of silicon of 1 mm thickness, while the last layer (absorbing) is equipped with thick CdTe or CZT sensors up to 2 mm in thickness. The total absorption of the whole detector can be very high if several CdTe or CZT layers are used. The maximal number of layers is not limited, but the practical evaluation was performed with 2 layers. Thanks to Timepix3 simultaneous measurement of ToA and energy, it is possible to precisely detect coincidence events in the detector layers. Based on the energy and position of these events, it is possible to estimate the possible direction of the original gamma. The angular resolution of the presented Compton camera depends on the detected energy, and it is in the order of 1 degree.

4D Cubism: Modeling, Animation, and Fabrication of Artistic Shapes.

This article deals with creating artistic shapes in a cubist style. The authors propose adding cubist features to (or cubification of) time-variant sculptural shapes. A new concept of a 4D cubist camera is introduced for multiple projections from 4D space-time to 3D space, and 3D printing for stop-motion animation is applied.

Simulation study of the second-generation MR-compatible SPECT system based on the inverted compound-eye gamma camera design

In this paper, we present simulation studies for the second-generation MRI compatible SPECT system, MRC-SPECT-II, based on an inverted compound eye (ICE) gamma camera concept. The MRC-SPECT-II system consists of a total of 1536 independent micro-pinhole-camera-elements (MCEs) distributed in a ring with an inner diameter of 6 cm. This system provides a FOV of 1 cm diameter and a peak geometrical efficiency of approximately 1.3% (the typical levels of 0.1%–0.01% found in modern pre-clinical SPECT instrumentations), while maintaining a sub-500 μm spatial resolution. Compared to the first-generation MRC-SPECT system (MRC-SPECT-I) (Cai 2014 Nucl. Instrum. Methods Phys. Res. A 734 147–51) developed in our lab, the MRC-SPECT-II system offers a similar resolution with dramatically improved sensitivity and greatly reduced physical dimension. The latter should allow the system to be placed inside most clinical and pre-clinical MRI scanners for high-performance simultaneous MRI and SPECT imaging.

Development of a SiPM based camera for Cherenkov Telescope Array

The Italian Institute of Nuclear Physics (INFN) is involved in the development of a prototype for a SiPM-based camera for the Cherenkov Telescope Array (CTA), a new generation of telescopes for ground - based gamma ray astronomy. In this framework, an R&D program for the development of SiPMs suitable for Cherenkov light detection (Near-Ultraviolet SiPMs) has been carried out. The developed device is a High Density NUV-SiPM based on a micro cell of 30 μm × 30 μm and 6 mm × 6 mm area produced by Fondazione Bruno Kessler (FBK). A full characterisation of the single SiPM will be presented and compared with the old technology (NUV-SiPM) and with other SiPMs commercially available. The NUV-HD SiPM will be tested in the pSCT (Schwarzschild-Couder Telescope prototype) for CTA which is leading to a camera concept based on 8 × 8 NUV-HD SiPM module as detection unit. An update on recent tests on the detectors arranged in this matrix configuration and on the front-end electronics will be given.