Prototype Imaging Research Articles

AN EFFICIENT METHOD FOR HAND GESTURE RECOGNITION USING ROBUST FEATURES VECTOR

Integration of technology for the Fourth Industrial Revolution (IR 4.0) has increased the need for efficient methods for developing dynamic human computer interfaces and virtual environments. In this context, hand gesture recognition can play a vital role to serve as a natural mode of interactive human machine interaction. Unfixed brightness, complex backgrounds, color constraints, dependency on hand shape, rotation, and scale variance are the challenging issues which have an impact on robust performance for the existing methods as per outlined in previous researches. This research presents an efficient method for hand gesture recognition by constructing a robust features vector. The proposed method is performed in two phases, where in the first phase the features vector is constructed by selecting interest points at distinctive locations using a blob detector based on Hessian matrix approximation. After detecting the area of the hand from the features vector, edge detection is applied in the isolated hand followed by edge orientation computation. After this, templates are generated using one and two dimensional mapping to compare candidate and prototype images using adaptive threshold. The proposed research performed extensive experimentation, where a recognition accuracy rate of 98.33% was achieved by it, which is higher as compared to previous research results. Experimental results reveal the effectiveness of the proposed methodology in real time.

Thin-Film Photodetector Optimization for High-Performance Short-Wavelength Infrared Imaging

In this letter, we present a small pixel pitch image sensor optimized for high external quantum efficiency in short-wavelength infrared (SWIR). Thin-film photodiodes based on PbS colloidal quantum dot (CQD) absorber allow us to exceed the spectral limitations of silicon’s absorption while maintaining the benefits of CMOS technology. By monolithically integrating PbS CDQ thin films with CMOS readout arrays, high-pixel density SWIR image sensors can be achieved. To overcome the remaining disadvantages of the CQD-based image sensors over their bulk III-V semiconductor counterparts (lower sensitivity and reduced linearity), the thin-film photodiode stack is adapted towards the used readout circuit. A prototype image sensor with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$768\times 512$ </tex-math></inline-formula> resolution of 5- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> pitch pixels is fabricated by using a modified 130 nm CMOS process for readout IC, together with the new CQD thin-film photodiode on top. Thanks to the optimized photodiode stack and co-integration process, the prototype image sensor shows less than 5% linearity error while having 40% external quantum efficiency in SWIR, which enables acquisition of high-quality images.

Simultaneous Detection of Viability and Concentration of Microalgae Cells Based on Chlorophyll Fluorescence and Bright Field Dual Imaging.

Ship ballast water contains high concentration of plankton, bacteria, and other microorganisms. If the huge amount of ballast water is discharged without being inactivated, it will definitely spell disaster to the marine environment. Microalgae is the most common species exiting in ballast water, so the detection of the concentration and viability of microalgae is a very important issue. The traditional methods of detecting microalgae in ballast water were costly and need the help of bulky equipment. Herein, a novel method based on microalgae cell intracellular chlorophyll fluorescence (CF) imaging combines with cell bright field (BF) microscopy was proposed. The geometric features of microalgae cells were obtained by BF image, and the cell viability was obtained by CF image. The two images were fused through the classic image registration algorithm to achieve simultaneous detection of the viability and concentration of microalgae cells. Furthermore, a low-cost, miniaturized CF/BF microscopy imaging prototype system based on the above principles was designed. In order to verify the effectiveness of the proposed method, four typical microalgae in ballast water (Platymonas, Pyramimonas sp., Chrysophyta, and Prorocentrum lima) were selected as the samples. The experimental results show that the self-developed prototype can quickly and accurately determine the concentration and the viability of microalgae cells in ship ballast water based on the dual images of BF and CF, and the detection accuracy is equivalent to that of commercial microscope. It was the first time to simultaneously detect the viability and concentration of microalgae cells in ship ballast water using the method that combining the fluorescence and bright field images; moreover, a miniaturized microscopic imaging prototype was developed. Those findings expected to contribute to the microalgae detection and ship ballast water management.

Large-Area Periodic Organic–Inorganic Hybrid Perovskite Nanopyramid Arrays for High-Performance Photodetector and Image Sensor Applications

The rapid growth of organic–inorganic hybrid perovskite materials (such as methylammonium lead triiodide, MAPbI3) in photoelectric applications has prompted investigations of novel strategies to improve photodetection performance. Although a few surface nanofabrication methods have been applied to texture perovskite thin films to enhance light trapping, it remains challenging to pattern large-area periodic perovskite nanoarrays in a tunable and scalable manner. In this work, we report a facile and low-cost approach to fabricate large-area SiO2/Si nanopyramids arrays through nanosphere lithography. These nanopyramids arrays are used to pattern MAPbI3 thin films. We find that the introduction of nanopyramid arrays enhances the light intensity within the perovskite film, which is confirmed by light absorption tests and optical simulations. As a result, the photodetectors based on MAPbI3 with nanopyramid structures show excellent responsivity of 28.8 ± 1.0 A/W and detectivity of (3.5 ± 0.1) × 1011 Jones at 650 nm. The photoresponse of the photodetector to pulsed light is highly stable and reproducible, with rise and decay times of ∼0.7 and 1.1 ms, respectively. They also have a broader light sensitivity range from ultraviolet to infrared light, i.e., 340 nm to 1100 nm, compared to those without nanostructures. Finally, we demonstrate a prototype image sensor using these photodetector arrays.

Achieving 256 × 256‐Pixel Color Images by Perovskite‐Based Photodetectors Coupled with Algorithms

AbstractPerovskites have been found with their exceptional optoelectronic properties that may bring new options to high‐performance cameras. However, the best images obtained by perovskite‐based photodetectors (PDs) have only 32 × 32 pixels, far below megapixels of camera images. In this study, a perovskite single‐PD color imaging prototype coupled with computation algorithms is fabricated, by which images with 256 × 256 pixels, whose quality has prevailed over those obtained by any perovskite‐based device so far are obtained. The technology shows its unique advantages by obtaining satisfying photographs, even when the PD is covered with frosted glass/moving smoke or facing a wall instead of the target, in addition to possessing some ability to resist ambient light interference. Moreover, a new Q factor is proposed to evaluate new‐material‐based PD for the imaging technology and prove its usability by comparing an atomic‐layer‐deposition (ALD)‐Al2O3 optimized CsBi3I10 PD and an unoptimized CsBi3I10 PD. Finally, the material choices are successfully extended to other types of perovskites, including photovoltaic MAPbI3 PD (structure: Spiro‐OMeTAD/MAPbI3/SnO2/FTO), ALD‐Al2O3 MAPbI3 PD, and ALD‐Al2O3 CsPbBr3 PD. The technology may bring an innovative approach to improve the performance of cameras and extend the application range of advanced functional materials.

Abbreviated on-treatment CBCT using roughness penalized mono-energization of kV-MV data and a multi-layer MV imager

Simultaneous acquisition of cone beam CT (CBCT) projections using both the kV and MV imagers of an image guided radiotherapy system reduces set-up scan times—a benefit to lung cancer radiation oncology patients—but increases noise in the 3D reconstruction. In this article, we present a kV‐MV scan time reduction technique that uses two noise-reducing measures to achieve superior performance. The first is a high-DQE multi-layer MV imager prototype. The second is a beam hardening correction algorithm which combines poly-energetic modeling with edge-preserving, regularized smoothing of the projections. Performance was tested in real acquisitions of the Catphan 604 and a thorax phantom. Percent noise was quantified from voxel values in a soft tissue volume of interest (VOI) while edge blur was quantified from a VOI straddling a boundary between air and soft material. Comparisons in noise/resolution performance trade-off were made between our proposed approach, a dose-equivalent kV-only scan, and a kV‐MV reconstruction technique previously published by Yin et al (2005 Med. Phys. 32 9). The proposed technique demonstrated lower noise as a function of spatial resolution than the baseline kV‐MV method, notably a 50% noise reduction at typical edge blur levels. Our proposed method also exhibited fainter non-uniformity artifacts and in some cases superior contrast. Overall, we find that the combination of a multi-layer MV imager, acquiring at a LINAC source energy of 2.5 MV, and a denoised beam hardening correction algorithm enables noise, resolution, and dose performance comparable to standard kV-imager only set-up CBCT, but with nearly half the gantry rotation time.

Random access DNA memory using Boolean search in an archival file storage system.

DNA is an ultrahigh-density storage medium that could meet exponentially growing worldwide demand for archival data storage if DNA synthesis costs declined sufficiently and if random access of files within exabyte-to-yottabyte-scale DNA data pools were feasible. Here, we demonstrate a path to overcome the second barrier by encapsulating data-encoding DNA file sequences within impervious silica capsules that are surface labelled with single-stranded DNA barcodes. Barcodes are chosen to represent file metadata, enabling selection of sets of files with Boolean logic directly, without use of amplification. We demonstrate random access of image files from a prototypical 2-kilobyte image database using fluorescence sorting with selection sensitivity of one in 106 files, which thereby enables one in 106N selection capability using N optical channels. Our strategy thereby offers a scalable concept for random access of archival files in large-scale molecular datasets.

Lake Qooqa as a Narrative: Finding Meanings in Social Memory (A Narrative Inquiry)

Lake Qooqa in Oromia/Ethiopia started out as a man-made lake back in the 1960s, formed by the damming of the Awash River and other rivers for a practical function, i.e., for hydroelectric power. The lake flooded over the surrounding picturesque landscape, shattered sacred sites and the livelihoods of the Siiba Oromo, and damaged the ecosystem in the area, which was later resuscitated to have an aesthetic function for tourists. Available sources showed that people used the lake for irrigation, washing, fishing, and drinking, while tanneries, flower farms, and manufacturing facilities for soap and plastic products were set up along the banks without enough environmental impact assessment and virtually with no regulations on how to get rid of their effluents, which contained dangerous chemicals such as arsenic, mercury, chromium, lead, and cadmium, giving the lake a blue and green color locally called bulee; hence, the name the “Green Lake”. In the present study, following a string of “narrative turns” in other disciplinary fields of humanities and social sciences (folklore, history, and anthropology), I use social memory and life hi/story narratives from Amudde, Arsi, Oromia/Ethiopia, to consider a few methodological and theoretical questions of folkloric and ecological nature in doing a narrative study: What is social memory? What does social memory reveal about the people and the environment in which they live? Is a personal narrative story folklore? Where do stories come from? What should the researcher do with the stories s/he collected? Hence, this study aims to tackle two objectives: first, using social memory data as a means to connect social identity and historical memory set in a social context in which people shape their group identity and debate conflicting views of the past, I explore the Green Lake as a narrative, which is, in its current situation, a prototypical image of degradation and anthropogenic impacts, and trace trajectories and meanings of social memory about the shared past, i.e., the historical grief of loss that people in the study area carry in their memory pool. Second, toward this end, I use people’s stories from the research site, particularly Amina’s story about the loss of seven members of her family from complications related to drinking the polluted water, as evidence to show, sharing Sandra Dolby Stahl’s claim, that the narrative of personal experience belongs in folklore studies to the established genre of the family story.

Adaptation of the polarimetric multi-spectral Aerosol Limb Imager for high altitude aircraft and satellite observations.

An elegant breadboard prototype of the Aerosol Limb Imager (ALI) has been developed to meet key performance parameters that will meet requirements for the retrieval of aerosol from the upper troposphere and stratosphere from limb scattered sunlight radiance measurements. Similar in concept to previous high altitude balloon-based generations, this instrument pairs a liquid crystal polarization rotator with an acousto-optic tunable filter to capture polarimetric multi-spectral images of the atmospheric limb. This design improves the vertical resolution, signal-to-noise ratio, and athermalization, all of which will facilitate observation from a moving high altitude aircraft platform, which provides a platform analogous to the spatially varying measurements that would be made from a satellite. Finally, a preliminary design is presented for a satellite-based generation of ALI.

Ohmic Dissipation‐Assisted Complex Amplitude Hologram with High Quality

AbstractTailoring the phase and amplitude of electromagnetic waves has drawn great attention in the microwave, terahertz, and even optics domains. However, the existing method for simultaneous control of these two essential properties suffers from inadequate efficiency and narrow bandwidth, especially for microwave devices. Here, a strategy of overcoming this difficulty is proposed by introducing the ohmic sheet into a Fabry–Pérot‐like cavity. The arbitrary phase modulation can be realized by changing the geometric parameters and the orientation of elliptical split resonance ring; via changing the intensity of ohmic dissipation, the amplitude can be continuously adjusted from 0 to 1. Its most significant advantage is arbitrary wide‐band complex‐amplitude modulation without introducing cross‐polarization crosstalk and backward scattering field interference. To verify its feasibility, three phase‐amplitude holographic imaging ​prototypes at 12, 14, and 16 GHz are designed. Both the simulated and measured results manifest the excellent performances of the proposed metasurface, demonstrating the excellent performances with a remarkable signal‐to‐noise ratio and low root‐mean‐square error. This proposed strategy provides an alternative method to control the phase and amplitude arbitrarily, which not only realizes high‐quality holography but also paves a way for random beamforming and so on.

Measuring Tumor Microenvironment pH During Radiotherapy Using a Novel Cerenkov Emission Multispectral Optical Probe Based on Silicon Photomultipliers

Cerenkov Emission (CE) multispectral analysis with silicon photomultiplier (SiPM)-based optical probes is a promising tool for online tumor microenvironment interrogation and targeting during radiotherapy delivery. With the extreme sensitivity of SiPMs, deep tissue multispectral CE measurements can be realized in a clinical setting. In this work, we utilize our Cerenkov Emission Multi-spectral Imaging (CMSI) prototype probe to interrogate the spectral components of the CE signal generated during external beam radiotherapy. Our results demonstrated that CMSI enables effective probing of in vitro quantitative changes in the pH of cell media to monitor cancer cell proliferation after various treatment pathways and differentiate between varying treatment resistance cell lines. In addition, the feasibility of using the CMSI probe in vivo was also successfully demonstrated by measuring tumor pH during a pilot mouse study.

Sparse Common Feature Representation for Undersampled Face Recognition

This work investigates the problem of undersampled face recognition (i.e., insufficient training data) encountered in practical Internet-of-Things (IoT) applications. Insufficient and uncertain samples captured by IoT devices may include background and facial disguise that makes face recognition more challenging than that with sufficient and reliable images. Many models work well in face recognition on a big data set, but when training data are insufficient, they achieve unsatisfactory performance. This work proposes a novel method named sparse common feature-based representation (SCFR) that provides a unique and stable result and completely avoids very time-consuming training required by a deep learning model. Specially, it constructs a common feature dictionary using both training and test images. Thereinto, a common feature is based on a discriminative common vector and learned by a Gaussian mixture model for both training and test images in a semisupervised learninig manner, which would reduce the difference among samples in each class. In the optimization, the latent indicator of test data is initialized by the estimated label. This can avoid learning invalid information and lead to good prototype images. A new variation dictionary characterizes variables that can be shared by different classes. Finally, this work adopts minimum reconstruction residuals to recognize test images, thus bringing about a substantial improvement in SCFR's performance. Extensive results on benchmark face databases demonstrate that the proposed method is better than the state-of-the-art methods handling undersampled face recognition.

Metasurface-Enhanced Antennas for Microwave Brain Imaging.

Stroke is a very frequent disorder and one of the major leading causes of death and disability worldwide. Timely detection of stroke is essential in order to select and perform the correct treatment strategy. Thus, the use of an efficient imaging method for an early diagnosis of this syndrome could result in an increased survival’s rate. Nowadays, microwave imaging (MWI) for brain stroke detection and classification has attracted growing interest due to its non-invasive and non-ionising properties. In this paper, we present a feasibility study with the goal of enhancing MWI for stroke detection using metasurface (MTS) loaded antennas. In particular, three MTS-enhanced antennas integrated in different brain scanners are presented. For the first two antennas, which operate in a coupling medium, we show experimental measurements on an elliptical brain-mimicking gel phantom including cylindrical targets representing the bleeding in haemorrhagic stroke (h-stroke) and the not oxygenated tissue in ischaemic stroke (i-stroke). The reconstructed images and transmission and reflection parameter plots show that the MTS loadings improve the performance of our imaging prototype. Specifically, the signal transmitted across our head model is indeed increased by several dB‘s over the desired frequency range of 0.5–2.0 GHz, and an improvement in the quality of the reconstructed images is shown when the MTS is incorporated in the system. We also present a detailed simulation study on the performance of a new printed square monopole antenna (PSMA) operating in air, enhanced by a MTS superstrate loading. In particular, our previous developed brain scanner operating in an infinite lossy matching medium is compared to two tomographic systems operating in air: an 8-PSMA system and an 8-MTS-enhanced PSMA system. Our results show that our MTS superstrate enhances the antennas’ return loss by around 5 dB and increases the signal difference due to the presence of a blood-mimicking target up to 25 dB, which leads to more accurate reconstructions. In conclusion, MTS structures may be a significant hardware advancement towards the development of functional and ergonomic MWI scanners for stroke detection.

Feasibility of lung imaging with a large field-of-view spectral photon-counting CT system

PurposeThe purpose of this study was to characterize the technical capabilities and feasibility of a large field-of-view clinical spectral photon-counting computed tomography (SPCCT) prototype for high-resolution (HR) lung imaging. Materials and methodsMeasurement of modulation transfer function (MTF) and acquisition of a line pairs phantom were performed. An anthropomorphic lung nodule phantom was scanned with standard (120kVp, 62mAs), low (120kVp, 11mAs), and ultra-low (80kVp, 3mAs) radiation doses. A human volunteer underwent standard (120kVp, 63mAs) and low (120kVp, 11mAs) dose scans after approval by the ethics committee. HR images were reconstructed with 1024 matrix, 300mm field of view and 0.25mm slice thickness using a filtered-back projection (FBP) and two levels of iterative reconstruction (iDose 5 and 9). The conspicuity and sharpness of various lung structures (distal airways, vessels, fissures and proximal bronchial wall), image noise, and overall image quality were independently analyzed by three radiologists and compared to a previous HR lung CT examination of the same volunteer performed with a conventional CT equipped with energy integrating detectors (120kVp, 10mAs, FBP). ResultsTen percent MTF was measured at 22.3lp/cm with a cut-off at 31lp/cm. Up to 28lp/cm were depicted. While mixed and solid nodules were easily depicted on standard and low-dose phantom images, higher iDose levels and slice thicknesses (1mm) were needed to visualize ground-glass components on ultra-low-dose images. Standard dose SPCCT images of in vivo lung structures were of greater conspicuity and sharpness, with greater overall image quality, and similar image noise (despite a flux reduction of 23%) to conventional CT images. Low-dose SPCCT images were of greater or similar conspicuity and sharpness, similar overall image quality, and lower but acceptable image noise (despite a flux reduction of 89%). ConclusionsA large field-of-view SPCCT prototype demonstrates HR technical capabilities and high image quality for high resolution lung CT in human.

Radiative lifetime-encoded unicolour security tags using perovskite nanocrystals

Traditional fluorescence-based tags, used for anticounterfeiting, rely on primitive pattern matching and visual identification; additional covert security features such as fluorescent lifetime or pattern masking are advantageous if fraud is to be deterred. Herein, we present an electrohydrodynamically printed unicolour multi-fluorescent-lifetime security tag system composed of lifetime-tunable lead-halide perovskite nanocrystals that can be deciphered with both existing time-correlated single-photon counting fluorescence-lifetime imaging microscopy and a novel time-of-flight prototype. We find that unicolour or matching emission wavelength materials can be prepared through cation-engineering with the partial substitution of formamidinium for ethylenediammonium to generate “hollow” formamidinium lead bromide perovskite nanocrystals; these materials can be successfully printed into fluorescence-lifetime-encoded-quick-read tags that are protected from conventional readers. Furthermore, we also demonstrate that a portable, cost-effective time-of-flight fluorescence-lifetime imaging prototype can also decipher these codes. A single comprehensive approach combining these innovations may be eventually deployed to protect both producers and consumers.

Imagination of the North in Context of Development of Natural Environment: Mammoth in Mythological Representations of Yakuts

A number of negative characters in Yakut mythology, as well as individual images of folklore, are considered. The point of view, according to which the basis for the emergence of certain mythological ideas among the Yakuts was the real world, the features of the landscape and climate, to the extent that they influenced a person, is proved. It is noted that the culture of the Sakha people is based on rich mythological concepts that have developed during the development of the vast expanses of the Arctic space. The authors analyze ethnographic notes of the XIX—XX centuries and modern scientific publications, which examine the mythology and folklore of the Sakha people (Yakuts). An attempt has been made to clarify the question of the influence of knowledge about the fossil remains of the mammoth fauna on the formation of mythological ideas related to the peculiarities of the climate of the region being developed. The image of a mammoth is analyzed in the broad context of the mythological views of the Yakuts. It is concluded that secondary esoteric ideas about mammoths, caused by the discovery of their remains, could form the basis of a prototypical image for a number of characters in Yakut mythology, for example, a water bull and a cold bull. It is proved that the idea of mammoths could be reflected in the external appearance of the abaasy heroes in the epic folklore of the Sakha.

Helium radiography with a digital tracking calorimeter—a Monte Carlo study for secondary track rejection

Radiation therapy using protons and heavier ions is a fast-growing therapeutic option for cancer patients. A clinical system for particle imaging in particle therapy would enable online patient position verification, estimation of the dose deposition through range monitoring and a reduction of uncertainties in the calculation of the relative stopping power of the patient.Several prototype imaging modalities offer radiography and computed tomography using protons and heavy ions. A Digital Tracking Calorimeter (DTC), currently under development, has been proposed as one such detector. In the DTC 43 longitudinal layers of laterally stacked ALPIDE CMOS monolithic active pixel sensor chips are able to reconstruct a large number of simultaneously recorded proton tracks.In this study, we explored the capability of the DTC for helium imaging which offers favorable spatial resolution over proton imaging. Helium ions exhibit a larger cross section for inelastic nuclear interactions, increasing the number of produced secondaries in the imaged object and in the detector itself. To that end, a filtering process able to remove a large fraction of the secondaries was identified, and the track reconstruction process was adapted for helium ions.By filtering on the energy loss along the tracks, on the incoming angle and on the particle ranges, 97.5% of the secondaries were removed. After passing through 16 cm water, 50.0% of the primary helium ions survived; after the proposed filtering 42.4% of the primaries remained; finally after subsequent image reconstruction 31% of the primaries remained. Helium track reconstruction leads to more track matching errors compared to protons due to the increased available focus strength of the helium beam. In a head phantom radiograph, the Water Equivalent Path Length error envelope was 1.0 mm for helium and 1.1 mm for protons. This accuracy is expected to be sufficient for helium imaging for pre-treatment verification purposes.

Modeling the system of beliefs that influence driving under the influence of cannabis (DUIC)

Cannabis use is increasing in the U.S. Driving under the influence of cannabis (DUIC) may be increasing as well potentially resulting in fatal and serious injury crashes. The purpose of this article is to explore the belief system associated with driving under the influence of cannabis (DUIC) using structural equation modeling (SEM). A sample (n = 2,084) of surveys collected from adults in the U.S. was analyzed using SEM to reveal the latent structure of the belief system associated with DUIC. The results of this analysis indicated that reported DUIC behavior (frequency and recency) was predicted by willingness that influenced intention. Willingness and intention were directly influenced by control beliefs, attitudes, norms, and attitudes (prototype image) toward people who never DUIC. Intention was also influenced by attitudes toward people who do DUIC. Intention had a stronger influence on DUIC than willingness alone. These components were influenced by underlying behavioral, normative, and control beliefs. Thus, strategies that can change these beliefs may also reduce DUIC.

A comprehensive cognitive-perceptual model of analysis for contextually determined components of a conceptualized term

The authors analyze major features of complex multidisciplinary analysis models of the recipient’s perceptual capacity related to desobjectifying contextually determined transdisciplinary borrowing of newly emerging components within a semantic hierarchy. Critical analysis and comparison are applied to some alternative approaches in linguistic studies of transdisciplinary terminologization. There is a role revealed, which belongs to the cognitive-perceptual aspect in the respective knowledge field. The comprehensive phenomenon of component transgression within the meaning hierarchy is viewed from different angles: metaphoric and metonymic explication, and from the stance of conceptual integration of mental spaces and grammatical constructions of implicit meaning generation. The semantic foundations of the frame &amp; semantic model of the borrowing theory serve a prototype of a comprehensive analytical model relevant not only in Linguistics, yet in other humanities (Literature, Psychology, Sociology). The comprehensive method of bottom-up analysis in studying explication of contextually determined overtones (forced reinterpretation of terms and terminoids) implies desobjectification of the semantic hierarchy at several levels. The analysis suggests that standard linguistic mechanisms can be employed through deautomation in the said cognitive modeling function. Reactivating a prototypical mental image within a new reflexive space is viewed as the most effective way of explicating the respective components.

Proof of concept image artifact reduction by energy-modulated proton computed tomography (EMpCT).

To reduce imaging artifacts and improve image quality of a specific proton computed tomography (pCT) prototype scanner by combining pCT data acquired at two different incident proton energies to avoid protons stopping in sub-optimal detector sections. Image artifacts of a prototype pCT scanner are linked to protons stopping close to internal structures of the scanner's multi-stage energy detector. We aimed at avoiding such protons by acquiring pCT data at two different incident energies and combining the data in post-processing from which artifact-reduced images of the relative stopping power (RSP) were calculated. Energy-modulated pCT (EMpCT) images were assessed visually and quantitatively and compared to the original mono-energetic images in terms of RSP accuracy and noise. Data were acquired for a homogeneous water phantom. RSP images reconstructed from the mono-energetic datasets displayed local image artifacts which were ring-shaped due to the homogeneity of the phantom. The merged EMpCT dataset achieved a superior visual image quality with reduced artifacts and only minor remaining rings. The inter-quartile range (25/75) of RSP values was reduced from 0.7% with the current standard acquisition to 0.2% with EMpCT due to the reduction of ring artifacts. In this study, dose was doubled compared to a standard scan, but we discuss strategies to reduce excess dose. EMpCT allows to effectively avoid regions of the energy detector that cause image artifacts. Thereby, image quality is improved.