Scanning Operation Research Articles

Construction of a cryogenic dual scanner magnetic force microscope equipped with piezoresistive cantilever

We present a low-temperature magnetic force microscope (MFM) incorporating a piezoresistive cantilever and a dual-range scanner for experiments across a wide temperature range from cryogenic levels to room temperature. The piezoresistor-based MFM eliminates the need for optical readjustment, typically required due to thermal expansion at varying temperatures, thereby providing a more stable and precise measurement environment. The integration of a dual scanner system expands the versatility of scanning operations, enabling accurate sample positioning for detailed exploration of magnetic and superconducting properties under diverse thermal conditions. To demonstrate the capabilities of our MFM, we show detailed imaging of Fe3GaTe2, a van der Waals ferromagnet, and Yb0.7Y0.3CuAs2, a ferromagnetic cluster glass material. These studies demonstrate the potential of our MFM in revealing intricate details of magnetic domain dynamics and contribute to our understanding of materials exhibiting the anomalous Hall effect as well as superconducting phenomena.

Automated intelligent measurement of cracks on bridge piers using a ring-climbing vision scanning operation robot

Detecting cracks on the surface of bridge piers is critical to the health condition of bridges. Aiming at the limitations of existing unmanned aerial vehicles (UAVs) and climbing robots, this research proposes a ring-climbing visual scanning operation robotic disease acquisition system, which achieves entire region, high-definition, and fast acquisition of cracks on bridge piers surfaces. In addition, a crack segmentation network based on an efficient self-attention mechanism and a refined segmentation algorithm are proposed to achieve accurate detection and quantification of cracks on bridge piers. Finally, an experimental prototype was built, and experiments were conducted. The results show that the maximum error of crack quantification is within 0.1 mm. The designed ring-climbing visual scanning operation robotic disease acquisition system can be applied to the surface of any pier with a 1.2 to 1.5 m diameter, which is of great significance for the automatic detection of the health condition of bridge piers.

In Vitro Analysis of the Accuracy of the Use of Waste Zirconia Dust Compared With Optical Scanning Spray on Implant Abutment Models in Extraoral Scanning Protocol.

Introduction The evolution of computer-aided design/computer-aided manufacturing(CAD/CAM) systems has heightened the significance of digital models in dentistry, particularly for fabricating prostheses like inlays, crowns, and bridges. While digital dentistry offers enhanced speed and precision, the initial investment in intraoral scanners may pose a barrier for some clinicians. Extraoral or lab scanners, however, offer a viable alternative, reducing laboratory time and providing accurate prostheses fit, though challenges such as reflective surfaces and availability of scanning sprays persist, impacting scanning quality and operator technique. Optical scanning using laboratory scanners is a routine practice in today's age of digital dentistry. Often these require powder opacification to record fine details. There arenumbered studies on the accuracy of scanning sprays. Materials and methods Tencasts, poured with type 4 dental stone (Elite Rock, Zhermack, Italy) with single implants, were used for the purpose of this study. Each cast was scanned by two different operators, using both mediums. It was scanned using an extraoral scanner (E4, 3Shape, Copenhagen,Denmark). Operator A used easy scan (Alphadent, Korea), followed by zirconia dust (Upcera, Guangdong, China), whereas operator B used zirconia dust first. Digital models within each group were superimposed individually to measure precision. Results Easy scan operator 1 and zirconia dust operator 1 differ by 0.16000 (p = 0.0802). In scenario 2, easy scan operator 2 and zirconia dust operator 2 differ by 0.21900 (p = 0.0212) . Operator type significantly affects performance, emphasizing the need to account for operator variability in relevant contexts. The trueness values obtained for zirconia dust and easy scan among both operators were statistically insignificant. Conclusion Zirconia dust can be reliably used for extraoral scanning of abutments in place of optical scanning sprays.

Hand-held electron spin resonance scanner for subcutaneous oximetry using OxyChip.

Electron spin resonance (ESR) is used to measure oxygen partial pressure (pO2) in biological media with many clinical applications. Traditional clinical ESR involves large magnets that encompass the subject of measurement. However, certain applications might benefit from a scanner operating within local static magnetic fields. Our group recently developed such a compact scanner for transcutaneous (surface) pO2 measurements of skin tissue. Here we extend this capability to subsurface (subcutaneous) pO2 measurements and verify it using an artificial tissue emulating (ATE) phantom. We introduce a new scanner, tailored for subcutaneous measurements up to 2 mm beneath the skin's surface. This scanner captures pulsed ESR signals from embedded approximate 1-mm oxygen-sensing solid paramagnetic implant, OxyChip. The scanner features a static magnetic field source, producing a uniform region outside its surface, and a compact microwave resonator, for exciting and receiving ESR signals. ESR readings derived from an OxyChip, positioned approximately 1.5 mm from the scanner's surface, embedded in ATE phantom, exhibited a linear relation of 1/T2 versus pO2 for pO2 levels at 0, 7.6, 30, and 160 mmHg, with relative reading accuracy of about 10%. The compact ESR scanner can report pO2 data in ATE phantom from an external position relative to the scanner. Implementing this scanner in preclinical and clinical applications for subcutaneous pO2 measurements is a feasible next phase for this development. This innovative design also has the potential to operate in conjunction with artificial skin graft for wound healing, combining therapeutic and pO2 diagnostic features.

Accessing Pyridines via a Nitrene Internalization Process

AbstractPyridines are valuable pharmacophores, and their access via direct and selective transmutation of carbon atom with desired nitrogen could become crucial in drug discovery processes. However, only scarce examples can be found when it comes C‐to‐N‐transmutation reactions of aromatics that could lead to the facile synthesis of pyridines or other azaarenes. In this context, Levin and co‐workers recently disclosed a process leading to pyridines from the corresponding aryl azides via the regioselective nitrene internalization process. Notably, the transformation did not lead to any further modification of the rest of the aromatic skeleton. This innovative work enabled selectively accessing various pyridine derivatives through direct nitrogen scan operations on benzene derivatives, which were otherwise not feasible.

Accessing Pyridines via a Nitrene Internalization Process.

Pyridines are valuable pharmacophores, and their access via direct and selective transmutation of carbon atom with desired nitrogen could become crucial in drug discovery processes. However, only scarce examples can be found when it comes C-to-N-transmutation reactions of aromatics that could lead to the facile synthesis of pyridines or other azaarenes. In this context, Levin and co-workers recently disclosed a process leading to pyridines from the corresponding aryl azides via the regioselective nitrene internalization process. Notably, the transformation did not lead to any further modification of the rest of the aromatic skeleton. This innovative work enabled selectively accessing various pyridine derivatives through direct nitrogen scan operations on benzene derivatives, which were otherwise not feasible.

The Accuracy of Full-Arch Intraoral Optical Impressions (IOS): Clinical Pilot Study of the Influence of the Scan Strategy, Operator, and Intraoral Scanner.

To investigate the influence of a novel scanning strategy-using two new intraoral scanner devices with different operators-on the full-arch scanning accuracy for a dentate maxilla. Two scanning strategies, a test and a control strategy, were used to produce full-arch impressions of the dentate maxilla of a study patient. Two intraoral scanning (IOS) devices were used. Five expert operators performed a total of 40 scans. The scan time was recorded for each. A reference model was obtained from the patient's maxillary arch with an analog impression. The model was later scanned with a high-precision laboratory scanner to create a digital reference model (DRM). The scanning accuracy was analyzed with 3D-analysis software using a root mean square (RMS) calculation method, and qualitative analysis was executed using machine learning software. The mean RMS result for the test strategy was 82.8 ± 16 μm compared to 81.5 ± 16 μm for the control strategy. The mean RMS results were 84.7 ± 15 μm for Primescan (PS) and 79.6 ± 17 μm for 3Shape (3S). As such, the scanning strategies and IOS devices did not influence the scanning accuracy. Yet, a significant difference was found when the two strategies' scanning times were compared (P = .001), as well as the IOS devices (P = .001). The operator was found to have no influence on the scanning strategy. The accuracy of digital impressions is not influenced by different strategies, devices, or operators, in contrast with the scanning time, which is influenced by both strategies and devices.

Correcting for Mobile X-Band Weather Radar Tilt Using Solar Interference

Precise knowledge of the antenna pointing direction is a key facet to ensure the accuracy of observations from scanning weather radars. The sun is an often-used reference point to aid accurate alignment of weather radar systems and is particularly useful when observed as interference during normal scanning operations. In this study, we combine two online solar interference approaches to determine the pointing accuracy of an X-band mobile weather radar system deployed for 26 months in northern England (54.517°N, 3.615°W). During the deployment, several shifts in the tilt of the radar system are diagnosed between site visits. One extended period of time (>11 months) is shown to have a changing tilt that is independent of human intervention. To verify the corrections derived from this combined approach, quantitative precipitation estimates (QPEs) from the radar system are compared to surface observations: an approach that takes advantage of the variations in the magnitude of partial beam blockage corrections required due to tilting of the radar system close to mountainous terrain. The observed improvements in QPE performance after correction support the use of the derived tilt corrections for further applications using the corrected dataset. Finally, recommendations for future deployments are made, with particular focus on higher latitudes where solar interference spikes show more seasonality than those at mid-latitudes.

A secure scan architecture using dynamic key to thwart scan-based side-channel attacks

Scan testing is widely used in the rigorous testing of modern integrated circuits. However, the controllable and observable nature of the scan design also provides opportunities for attackers who can utilise this structure to steal secret information stored in the chip. This paper proposes a secure Design for Testability (DFT) architecture to prevent scan-based attacks. The scheme uses a modified Linear Feedback Shift Register (LFSR) to dynamically generate keys for the scan design key generator and verifies them against a specific selection of test key flip-flops in the original scan chain, and locks the control signals by transmitting the outputs of the verification comparisons to a OR gate. When the test authorisation key is correct, the circuit performs a normal scan operation; otherwise, the circuit enters an abnormal test mode and the data in the scan chain is dynamically obfuscated, thus preventing from observing valid data or deriving an encryption key through the output of the scan chain.

Developments in scan shift power reduction: a survey

While power reduction during testing is necessary for today's low-power devices, it also lowers test costs. Scan-based methods are the most widely used approach for testing integrated circuits (IC). Test vectors are shifted into and out of scan chains bit by bit during shift operation. The time required for shift operation dominates the test time. With the geometries shrinking (7 nm→5 nm→3 nm→1.8 nm), ICs are required to be tested for newer defects, increasing test time. The most effective way to reduce test time for scan operation is to increase the frequency of the shift operation. Reduction in shift power enables scan operation to be performed with increased frequency, reducing test time, and test cost. This paper presents a survey of techniques proposed recently for shift power reduction. Various techniques, including special flip-flop usage, segmentation, reordering, and low-pass filter, are being reviewed. The techniques are organized based on main attributes to underscore their similarities and differences. Pros and cons in terms of complexities involved in their implementation are discussed. We believe this paper will provide a point of reference for further studies in scan shift power reduction and will be helpful to both industry and academia.

A Simple and Economical System for Automatic Near-Field Scanning for Power Electronics Converters

Electromagnetic compatibility issues must be considered from the early steps in the design of electronic devices. A specific topic is the near-field emission generated by the device due to the traces on a printed circuit board and the specific routing. The analysis of near-field emission is essential to detect potential electromagnetic interference with nearby devices. This problem is crucial in high power density applications. Therefore, especially in these applications, it is necessary to optimize the circuit and the layout to minimize the generated noise. The design and construction of systems able to scan volumes to determine the spatial distribution of electrical E and/or magnetic B fields in the near-field region of a device under test is a very complex process. The realization of equipment that explores a given surface at a given distance from the device is easier. The main purpose of this paper is to show how it is possible to build a cheap two-dimensional scanner, starting from simple hardware not explicitly designed for near-field scan operations. The presented firmware and software solution can map, with good accuracy, the spatial distribution of fields B and E on a fixed plan close to the board. Finally, the developed system has been used in a GaN-based bi-directional DC/DC Converter.

Influence of Intraoral Scanners, Operators, and Data Processing on Dimensional Accuracy of Dental Casts for Unsupervised Clinical Machine Learning: An In Vitro Comparative Study.

This study assessed the impact of intraoral scanner type, operator, and data augmentation on the dimensional accuracy of in vitro dental cast digital scans. It also evaluated the validation accuracy of an unsupervised machine-learning model trained with these scans. Twenty-two dental casts were scanned using two handheld intraoral scanners and one laboratory scanner, resulting in 110 3D cast scans across five independent groups. The scans underwent uniform augmentation and were validated using Hausdorff's distance (HD) and root mean squared error (RMSE), with the laboratory scanner as reference. A 3-factor analysis of variance examined interactions between scanners, operators, and augmentation methods. Scans were divided into training and validation sets and processed through a pretrained 3D visual transformer, and validation accuracy was assessed for each of the five groups. No significant differences in HD and RMSE were found across handheld scanners and operators. However, significant changes in RMSE were observed between native and augmented scans with no specific interaction between scanner or operator. The 3D visual transformer achieved 96.2% validation accuracy for differentiating upper and lower scans in the augmented dataset. Native scans lacked volumetric depth, preventing their use for deep learning. Scanner, operator, and processing method did not significantly affect the dimensional accuracy of 3D scans for unsupervised deep learning. However, data augmentation was crucial for processing intraoral scans in deep learning algorithms, introducing structural differences in the 3D scans. Clinical Significance. The specific type of intraoral scanner or the operator has no substantial influence on the quality of the generated 3D scans, but controlled data augmentation of the native scans is necessary to obtain reliable results with unsupervised deep learning.

Improving domain generalization performance for medical image segmentation via random feature augmentation.

Deep convolutional neural networks (DCNNs) have shown remarkable performance in medical image segmentation tasks. However, medical images frequently exhibit distribution discrepancies due to variations in scanner vendors, operators, and image quality, which pose significant challenges to the robustness of trained models when applied to unseen clinical data. To address this issue, domain generalization methods have been developed to enhance the generalization ability of DCNNs. Feature space-based data augmentation methods have been proven effective in improving domain generalization, but they often rely on prior knowledge or assumptions, which can limit the diversity of source domain data. In this study, we propose a novel random feature augmentation (RFA) method to diversify source domain data at the feature level without prior knowledge. Specifically, our RFA method perturbs domain-specific information while preserving domain-invariant information, thereby adequately diversifying the source domain data. Furthermore, we propose a dual-branches invariant synergistic learning strategy to capture domain-invariant information from the augmented features of RFA, enabling DCNNs to learn a more generalized representation. We evaluate our proposed method on two challenging medical image segmentation tasks, optic cup/disc segmentation on fundus images and prostate segmentation on MRI images. Extensive experimental results demonstrate the superior performance of our method over state-of-the-art domain generalization methods.

Quality Management System in Clinical Digital Pathology Operations at a Tertiary Cancer Center

Digital pathology workflows can improve pathology operations by allowing reliable and fast retrieval of digital images, digitally reviewing pathology slides, enabling remote work and telepathology, use of computer-aided tools, and sharing of digital images for research and educational purposes. The need for quality systems is a prerequisite for successful clinical-grade digital pathology adoption and patient safety. In this article, we describe the development of a structured digital pathology laboratory quality management system (QMS) for clinical digital pathology operations at Memorial Sloan Kettering Cancer Center (MSK). This digital pathology–specific QMS development stemmed from the gaps that were identified when MSK integrated digital pathology into its clinical practice. The digital scan team in conjunction with the Department of Pathology and Laboratory Medicine quality team developed a QMS tailored to the scanning operation to support departmental and institutional needs. As a first step, systemic mapping of the digital pathology operations identified the prescan, scan, and postscan processes; instrumentation; and staffing involved in the digital pathology operation. Next, gaps identified in quality control and quality assurance measures led to the development of standard operating procedures and training material for the different roles and workflows in the process. All digital pathology–related documents were subject to regulatory review and approval by departmental leadership. The quality essentials were developed into an extensive Digital Pathology Quality Essentials framework to specifically address the needs of the growing clinical use of digital pathology technologies. Using the unique digital experience gained at MSK, we present our recommendations for QMS for large-scale digital pathology operations in clinical settings.

Procedural Point Cloud Modelling in Scan-to-BIM and Scan-vs-BIM Applications: A Review

Point cloud processing is an essential task in many applications in the AEC domain, such as automated progress assessment, quality control and 3D reconstruction. As much of the procedure used to process the point clouds is shared among these applications, we identify common processing steps and analyse relevant algorithms found in the literature published in the last 5 years. We start by describing current efforts on both progress and quality monitoring and their particular requirements. Then, in the context of those applications, we dive into the specific procedures related to processing point clouds acquired using laser scanners. An emphasis is given to the scan planning process, as it can greatly influence the data collection process and the quality of the data. The data collection phase is discussed, focusing on point cloud data acquired by laser scanning. Its operating mode is explained and the factors that influence its performance are detailed. Data preprocessing methodologies are presented, aiming to introduce techniques used in the literature to, among other aspects, increase the registration performance by identifying and removing redundant data. Geometry extraction techniques are described, concerning both interior and outdoor reconstruction, as well as currently used relationship representation structures. In the end, we identify certain gaps in the literature that may constitute interesting topics for future research. Based on this review, it is evident that a key limitation associated with both Scan-to-BIM and Scan-vs-BIM algorithms is handling missing data due to occlusion, which can be reduced by multi-platform sensor fusion and efficient scan planning. Another limitation is the lack of consideration for laser scanner performance characteristics when planning the scanning operation and the apparent disconnection between the planning and data collection stages. Furthermore, the lack of representative benchmark datasets is hindering proper comparison of Scan-to-BIM and Scan-vs-BIM techniques, as well as the integration of state-of-the-art deep-learning methods that can give a positive contribution in scene interpretation and modelling.

3D SURVEY AND DATA PROCESSING OF BOLIVIAN ARCHAEOLOGY: THE RITUAL RECEPTACLE FROM TIWANAKU

Abstract. The archaeological site of Tiwanaku is among the most important examples of Bolivian archaeology and UNESCO World Heritage Site since 2000. This works reports a geomatic-based surveying and modelling methodology applied to a ritual receptacle excavated from the semi-subterranean temple in the archaeological complex. A high-resolution 3D survey was conducted through structured-light projection scanning and post-processing operations were carried out to emphasize surface details. Most of the operations were conducted in open-source software, with the aim to establish a quick and repeatable methodology to be applied to similar case studies. The final outputs, consisting of geometry projections (unrolled meshes), digitally enhanced surfaces and vector graphics can support the work of archaeologists in interpreting the iconography depicted on the receptacle and to conduct further studies to shed light about culture and religion of the civilization that inhabited Tiwanaku.

Updatable Learned Indexes Meet Disk-Resident DBMS - From Evaluations to Design Choices

Although many updatable learned indexes have been proposed in recent years, whether they can outperform traditional approaches on disk remains unknown. In this study, we revisit and implement four state-of-the-art updatable learned indexes on disk, and compare them against the B+-tree under a wide range of settings. Through our evaluation, we make some key observations: 1) Overall, the B+-tree performs well across a range of workload types and datasets. 2) A learned index could outperform B+-tree or other learned indexes on disk for a specific workload. For example, PGM achieves the best performance in write-only workloads while LIPP significantly outperforms others in lookup-only workloads. We further conduct a detailed performance analysis to reveal the strengths and weaknesses of these learned indexes on disk. Moreover, we summarize the observed common shortcomings in five categories and propose four design principles to guide future design of on-disk, updatable learned indexes: (1) reducing the index's tree height, (2) better data structures to lower operation overheads, (3) improving the efficiency of scan operations, and (4) more efficient storage layout.

Ultrasound-guide prostate biopsy robot and calibration based on dynamic kinematic error model with POE formula

In the transrectal ultrasound-guided transperineal prostate biopsy, the application of robots can effectively reduce the interference of low-quality ultrasound images on the physician to determine the biopsy route and improve the positive detection rate. In this paper, an 8-degree-of-freedom (DOF) prostate biopsy robot for clinical is developed to realize the operation of ultrasonic probe scanning, the inserting point and target lesion point positioning, and the needle insertion. Considering the dynamic errors caused by different motions of robot joints, a dynamic product-of-exponentials (POE) based kinematic model that can reflect non-geometric errors is proposed by integrating the errors into each joint. Moreover, the parameters in the model are identified by linearizing the dynamic POE-based kinematic model. Finally, the experiment shows the maximum errors can be limited to 0.60 and 1.16 mm for inserting point and needle endpoint after compensation, and the maximum inserting angle error is limited to 1.381°. It proves the feasibility of the kinematic model proposed in this paper and indicates that the robot system can meet the requirements of clinical biopsy.

Use of scanners for colorimetric analysis of microfluidic paper-based analytical devices (µPADs): A practical guide

Office style scanners are often used by researchers for the colorimetric detection in the development of microfluidic paper-based analytical devices (µPADs). However, little attention has been paid to nuances in calibration curve responses caused by varying settings of a single image-capturing device. Hence, in this study, the effect of parameters, such as the scanner operation conditions, the method of data analysis used (e.g., choice of colour space system, suitable channel), and the influence of the physical characteristics of the µPAD (e.g., template colour, type of lamination pouches used) on the colorimetric detection were evaluated for the first time.Combinations of the scanning parameters were thoroughly examined and their impact on the quality of a mock calibration curve assessed. The most sensitive calibration curve was achieved only by the selection of the optimal scanning conditions combined with an appropriate choice of colorimetric system. A flatbed scanner, used in this study, showed greater variation of signal with varying scanning setup, whereas a portable scanner provided nearly identical responses under diverse scanning conditions. Gamma correction, scanning resolution, region of interest (ROI) surrounding colour (i.e., template colour), bit-depth, image file type, and the number of analysed pixels were found not to markedly affect the dynamics of the calibration curve when colour in the ROI is homogeneous. Parameters that had an effect on the colorimetric detection were the scanner settings, colour of the blank, image acquisition mode (colour vs greyscale), and µPAD covering (e.g., lamination). Based on these findings, generic guidelines for optimal data acquisition and µPAD manipulation with respect to µPAD calibration have been formulated.

BIM-based scan planning for scanning with a quadruped walking robot

Scan positioning for documenting the geometry of an existing building still relies on the experience of an expert surveyor. Therefore, it is important to utilize optimal scan positioning for an automated scanning process with an autonomous robot platform. This study presents an automated framework to determine the optimal scan planning for a stop-and-go mapping procedure with a quadruped walking robot based on BIM. The proposed framework comprises four main phases: Generation of scan-position candidates; optimal scan positioning; ordering of the optimal scan positions; data collection with an autonomous scanning system. The experimental results showed that the proposed framework presented better performance than those of the conventional approaches. Furthermore, the number of scan positions and the scan operation time were significantly reduced compared with manual scanning by skilled surveyors in real-world indoor environments. A future work will focus on an automated registration process and enhancement of computational performance.