Scanning Device Research Articles

Target-surface multiplexed quantitative dynamic phase microscopic imaging based on the transport-of-intensity equation.

Microscopic phase digital imaging based on the transport of intensity equation, known as TIE, is widely used in optical measurement and biomedical imaging since it can dispense with the dependence of traditional phase imaging systems on mechanical rotational scanning and interferometry devices. In this work, we provide a single exposure target-surface multiplexed phase reconstruction (SETMPR) structure based on TIE, which is remarkably easy to construct since it directly combines a conventional bright-field inverted microscope with a special image plane transmission structure that is capable of wavefront shaping and amplification. In practice, the SETMPR is able to achieve dynamic, non-interferometric, quantitative refractive index distribution of both static optical samples and dynamic biological samples in only one shot, meaning that the only limitation of measuring frequency is the frame rate. By comparing the measurement results of a microlens array and a grating with a standard instrument, the quantitative measurement capability and accuracy are demonstrated. Subsequently, both in situ static and long-term dynamic quantitative imaging of HT22 cells were performed, while automatic image segmentation was completed by introducing machine learning methods, which verified the application prospect of this work in dynamic observation of cellular in the biomedical field.

An Enhanced Methodology for Creating Digital Twins within a Paleontological Museum Using Photogrammetry and Laser Scanning Techniques

In recent years, researchers in the field of natural heritage have intensified their efforts to develop new ways to enhance the promotion and accessibility of natural content in order to attract more audiences using virtual representations of physical objects (digital twins). Therefore, they are increasingly incorporating new technologies and digital tools in their operations since their usage by the general public and in the natural heritage (NH) museums is considered particularly effective. Simultaneously, the increasing quality of the produced digitizations has opened up new opportunities for the exploitation of the outcomes of digitization beyond the initial anticipations. Responding to the growing demand of museum visitors for a personalized digital tour experience, especially amidst the recent COVID-19 pandemic, the v-PalM project aims to develop a digital platform to offer virtual guidance and education services at the Museum of Paleontology and Geology, which is hosted at the National Kapodistrian University of Athens. The development of the platform will be based on collecting data through various methods, including crowdsourcing, innovative information, and communication technologies, taking advantage of content digitization using 3D scanning devices. This paper demonstrates an enhanced methodology for the digitization of paleontological exhibits. The methodology uses photogrammetry and laser scanning methods from various devices, such as drones, laser scanners, and smartphones. These methods create digital twins that are suitable for various scenarios, including research, education, and entertainment. The proposed methodology has been applied to over fifty paleontological museum exhibits of varying sizes and complexities, and the resulting 3D models exhibit high accuracy in both their material and geometric aspects, while they also feature crucial details that assist researchers and the scientific community.

Microwave dielectric properties and frequency-controlled beam scanning application of Nb5+-substituted calcium-magnesium vanadate low-temperature sintered ceramics

Beam scanning devices in the X-band allow spatial reorientation of the beam, but this poses challenges for material and device design. To meet such challenges, the development of microwave dielectric materials and the design of special structures are crucial. Here, the microwave dielectric properties of Ca5Mn4V6-xNbxO24 (x = 0.00–0.08) ceramics are systematically investigated by using first-principles calculations and microstructural analysis. The ceramic has the best microwave dielectric properties (εr = 10.92 ± 0.14, Q × f = 50032 ± 1795 GHz (@10.52 GHz), τf = −59.58 ± 3.81 ppm/°C) when x = 0.04 and T = 875 °C. As a concept demonstration for device applications, a frequency-controlled beam scanning device in the X-band is designed by using this ceramic and copper electrode. This device has a beam scanning space of 3.248° (from 27.143° to 32.371°) in the frequency range of 10–11 GHz while maintaining high reflectivity (≥0.6). This function is verified by simulation results for far-field amplitude and far-field phase. This work contributes to the application of microwave dielectric ceramics.

Survey of Point Cloud Registration Methods and New Statistical Approach

The use of a 3D range scanning device for autonomous object description or unknown environment mapping leads to the necessity of improving computer methods based on identical point pairs from different point clouds (so-called registration problem). The registration problem and three-dimensional transformation of coordinates still require further research. The paper attempts to guide the reader through the vast field of existing registration methods so that he can choose the appropriate approach for his particular problem. Furthermore, the article contains a regression method that enables the estimation of the covariance matrix of the transformation parameters and the calculation of the uncertainty of the estimated points. This makes it possible to extend existing registration methods with uncertainty estimates and to improve knowledge about the performed registration. The paper’s primary purpose is to present a survey of known methods and basic estimation theory concepts for the point cloud registration problem. The focus will be on the guiding principles of the estimation theory: ICP algorithm; Normal Distribution Transform; Feature-based registration; Iterative dual correspondences; Probabilistic iterative correspondence method; Point-based registration; Quadratic patches; Likelihood-field matching; Conditional random fields; Branch-and-bound registration; PointReg. The secondary purpose of this article is to show an innovative statistical model for this transformation problem. The new theory needs known covariance matrices of identical point coordinates. An unknown rotation matrix and shift vector have been estimated using a nonlinear regression model with nonlinear constraints. The paper ends with a relevant numerical example.

Unmanned aerial vehicle orthogonal laser localization by Gaussian mixture model‐based map representation

AbstractLocalization is a core problem in mobile robot navigation. Simultaneous localization and mapping (SLAM) costs much for an unmanned aerial vehicle (UAV). This research aims to design an orthogonal laser scan device for localization and to save computation costs. Based on disturbance analysis, residual influences on sensor state are quantitative, and they are related to uncertainty and sensitivity. This research applied the residual selection method to a UAV. The feature point detection utilises multi‐scale and Gaussian model fitting techniques to guarantee true positives. The map is represented by Gaussian Mixture Models (GMM) with lower memory costs. The orthogonal laser scan device is composed and placed on a UAV for real‐time three‐dimensional localization, whose errors are at the centimeter level.

Geometrical digital twins of the as-built microstructure of three-leaf stone masonry walls with laser scanning

Research on irregular stone masonry walls is hampered by the lack of detailed geometrical models of their internal micro-structure, i.e. the shape and size of each stone and its position within the wall. Without such a geometric digital twin of walls tested in the laboratory, it is difficult to evaluate the accuracy of existing numerical simulation techniques. Here, we describe the generation of geometrical digital twins of three irregular stone masonry walls built in the laboratory. We labelled each stone manually and then obtained the geometry of the individual stones using a portable laser scanning device. With the same device we scanned the wall after the construction of each layer. We then registered the position of each stone in the layer. This paper outlines the methodology for the data acquisition and digital reconstruction and presents the datasets for the walls. The developed geometrical digital twins provide unique information regarding the micro-structure of constructed walls that is key for the development and validation of numerical simulation techniques for stone masonry.

Phased Array Ultrasonic Testing for Inspection of LNG Storage Tank

Liquefied natural gas (LNG) is liquefied at -162°C at atmospheric pressure and stored in the inner shell. Due to the transport and storage characteristics of such low temperature conditions, 9% high nickel steel, which shows excellent strength and toughness even at low temperatures, is used for the inner wall. On the other hand, the base material of the inner wall has a tempered martensite structure, whereas the weld metal has an Inconel- based austenite structure with high damping properties in acoustics. Also, the weld metal is composed of an anisotropic structure completely different from the base material. These are considered obstacles in non-destructive testing. We applied automated phased array ultrasonic testing(PAUT) as a replacement of radiographic testing in inspection of LNG storage tank. To obtain the reference value data, a reference specimen for each thickness was prepared, and an automatic scanning device was designed and manufactured. Also, a customized phased array(PA) probe was developed and applied. All parts are integrated and operated as one system, and the data is analyzed and stored through an operating program developed in-house. The current system has proven its performance through field application to a much-improved level in the existing scanning device, probe and application method. In conclusion, it was proved that our technology can be commercialized by showing excellent detection ability.

Fundus Imaging-Based Healthcare: Present and Future

A fundus image is a two-dimensional pictorial representation of the membrane at the rear of the eye that consists of blood vessels, the optical disc, optical cup, macula, and fovea. Ophthalmologists use it during eye examinations to screen, diagnose, and monitor the progress of retinal diseases or conditions such as diabetes, age-marked degeneration (AMD), glaucoma, retinopathy of prematurity (ROP), and many more ocular ailments. Developments in ocular optical systems, image acquisition, processing, and management techniques over the past few years have contributed to the use of fundus images to monitor eye conditions and other related health complications. This review summarizes the various state-of-the-art technologies related to the fundus imaging device, analysis techniques, and their potential applications for ocular diseases such as diabetic retinopathy, glaucoma, AMD, cataracts, and ROP. We also present potential opportunities for fundus imaging–based affordable, noninvasive devices for scanning, monitoring, and predicting ocular health conditions and providing other physiological information, for example, heart rate (HR), blood components, pulse rate, heart rate variability (HRV), retinal blood perfusion, and more. In addition, we present different types of technological, economical, and sociological factors that impact the growth of the fundus imaging–based technologies for health monitoring.

Fisheye lens-based UWOC system with an FOV of ±90°.

The link alignment is a challenge in underwater wireless optical communication (UWOC). This paper proposes a UWOC system adopting a fisheye lens with a field of view (FOV) of ±90° at the receiver to alleviate alignment requirement, and a mobile scanning device (MSD) is exploited to track the variation of the imaging position generated by the fisheye lens due to different incidence angles. In a 7-m tap water channel, a transmission with a data rate of 400 Mbps and an FOV of ±90° is realized with 16-quadrature amplitude modulating-orthogonal frequency division multiplexing (16-QAM-OFDM) modulation and orthogonal matching pursuit (OMP) channel estimation algorithm.

Construction of a radiation beam scanner and investigation of volume averaging correction factor effects on beam-profile.

In radiation beam-profile measurements, an accurate positioning of the detector with high position resolution is essential. For this purpose, we built a scanning device capable of moving a detector in three dimensions (3D) using mainly parts from a commercial 3D-printer. The accuracy and repeatability of movement was tested with caliper, laser displacement sensor and repeated 60Co beam-profile measurements in a water phantom. The results from the caliper and the sensor showed position accuracy for the scanner to be better than $\pm$150μm. The standard deviation of the error in position from laser sensor measurements was approximately 30μm, and the beam profile scans showed a maximum deviation from the mean position of 50μm. The effect of volume averaging correction factors on 60Co beam-profile was investigated with two different sized ionization chambers. The differences in the profiles were reduced significantly after applying the correction factors.

Quasi-phase extraction-based surface plasmon resonance imaging method for coffee ring effect monitoring and biosensing.

Wavelength interrogation surface plasmon resonance imaging (WSPRi) sensing has unique advantages in high-throughput imaging detection. The refractive index resolution (RIR) of WSPRi is limited to the order of 10-6 RIU. This paper demonstrates a novel WSPRi sensing system with a wavelength scanning device of an acousto-optic tunable filter (AOTF) and a low-cost speckle-free SPR excitation source of a halogen lamp. We developed a sensitive quasi-phase extraction method for data processing. The new technique achieved an RIR of 8.84×10-7 RIU, which is the first WSPRi system that has an RIR in the order of 10-7 RIU. Moreover, we performed a real-time recording of the formation of the coffee ring effect during brine evaporation and enhanced the biosensor performance of SPR for the first time. We believe the higher RIR and accuracy of the system will benefit more potential applications toward exploring the biomolecules' behaviors in biological and biochemistry studies.

Effects of Eight-week Dynamic Neuromuscular Stabilization Exercises on the Static and Dynamic Balance of Educable Mentally Retarded Female Students

Background and Aims Balance is an important factor in people with intellectual disability to have an independent life. These people are weak static and dynamic balance due to lack of development in their central nervous system, defects in the sensory-motor pathways, and having a sedentary life. This study aims to determine the effect of eight weeks of dynamic neuromuscular stabilization (DNS) exercises on static and dynamic balance of educable mentally retarded female students Methods In this study, participants were 26 educable mentally retarded female students aged 15-20 years (Mean age: 17.19±1.50 years, IQ: 61.15±6.07, weight: 58.9±12.73 kg, height: 157.92±6.07 cm) who were selected using purposive and convenience sampling methods and randomly divided into two groups of training (n=13) and control (n=13). Before and after training, their static balance and dynamic balance on the right and left feet were evaluated using a foot scan device. Subjects in the training group performed DNS exercises at 24 sessions, each session for 40 minutes. No intervention was provided to the control group; they performed their routine activities. Repeated measures analysis of variance was used to analyze the data. The significance level was set at 0.05. Results After eight weeks of DNS exercises, the results showed a significant improvement in static balance (F=72.54, P=0.001), dynamic balance on the right foot (F=90.90, P=0.002) and dynamic balance on the left foot (F=61.58, P=0.001) in the training group compared to the pretest scores and compared to the control group. Conclusion DNS exercises can be used as an effective method to improve static and dynamic balance of educable mentally retarded female students.

FAST OR EXTENSIVE? COMPARING WORKFLOWS FOR THE GEOMETRICAL ANALYSIS OF THE BUILT HERITAGE

Abstract. Three-dimensional digitization has been widely used for the documentation of built heritage. This paper presents two different approaches to the three-dimensional documentation of historic buildings using active 3D Terrestrial Laser Scanning (TLS) devices and data integration from other heterogeneous sources. Both methods aim to produce accurate and complete 3D surveys by integrating data from other sources, such as historical photographs, conservation reports, and traditional drawings, to enable a geometric analysis of the buildings. The first approach aims for completeness and redundancy of geometric information. The second method focuses on rapidness and is suitable for situations where the building is not easily accessible. The two approaches are applied to the case studies of Diotti Palace in Milan and Uzbekistan Hotel in Tashkent, demonstrating the efficiency of the two different datasets for analyzing the built heritage. The paper compares these two approaches and highlights their advantages and drawbacks in terms of the reliability of the resulting data. The study shows how two different methodologies can be adopted in different scenarios to obtain a comprehensive database for reliable and in-depth analysis of historic buildings.

Compact and Low Power-Consumption Solid-State Two-Dimensional Beam Scanner Integrating a Passive Optical Phased Array and Hybrid Wavelength-Tunable Laser Diode

Large-scale optical phased arrays have attracted attention as devices for solid-state beam scanning employing light detection and ranging. However, conventional optical phased arrays using electro-optic phase shifters require active phase control for each antenna. Because the power consumption of the active phase shifters is proportional to the number of antennas, the total power consumption increases in a large-scale optical phased array with a narrow beam divergence. In this study, we propose a passive beam scanner that realizes two-dimensional beam scanning through the wavelength sweep of a laser light. Additionally, most studies on optical phased arrays use external laser diodes as light sources. This increases the size of the beam-scanning system. Therefore, there is a demand for integrating an optical phased array and a laser light source in a combined chip. In this study, we integrated a 64-channel passive optical phased array and a hybrid wavelength-tunable laser diode into a combined chip. The size of the device was 5 mm × 1.5 mm, and the power consumption for beam scanning was 49.3 mW. The field of view was 44.2° × 13.7°, and the full width at half maximum of the beam divergence was 0.517° × 3.67°. Compared with the device used in a previous study, our device was nine times smaller, and the total power consumption was only tens of milliwatts. This device consumes less power and achieves a fully integrated light detection and ranging.

FORM-based Document Understanding Sequential Model

Abstract: Image recognition and optical character recognition technologies have become an integral part of our daily lives due to the ever-increasing power of computing and the ubiquity of scanning devices. Sequence modeling has performed state-of-theart on natural. Language and document comprehension tasks. However, this is the challenge of properly serializing tokens into form-like documents in practice due to the variety of layout patterns. We propose FormNet, a structure-aware layout model that reduces most serialization of forms. Form-based documents with the help of the OCR, we can search and recognize the text in documents and can easily convert them into human-readable text. It motivates us to make life simple to read the data which is unstructured as we convert it into a structured and simple format so that it becomes easy to read vast textual data.

Text Recognition Using Image Processing Technology for Visiting Card

Abstract: Image recognition and optical character recognition technologies have become an integral part of our daily lives due to increasing computing power and the proliferation of scanning devices. A printed document can be quickly converted to a digital text file using optical character recognition and edited by the user. The time required to digitize documents is therefore minimal. This is especially useful when archiving large print volumes. In this study, we show how image processing techniques can be used in combination with optical character recognition to improve recognition accuracy and improve efficiency in extracting text from images. Two of his software systems are developed and tested in this study: a character recognition system applied to cosmetics-related advertising images and a recognition and text recognition system for natural scenes. Experimental results show that the proposed system can accurately recognize text in images. Keywords: Image processing, Text detection, Visiting card, Optical character recognition (OCR),Named entity recognition (NER),Computer vision, OpenCV, Pytesseract, Tesseract OCR engine, Grayscale conversion, Noise removal, Thresholding, Named entities, Business name extraction, Owner name extraction, Address extraction, Contact number extraction, Email address extraction, Website extraction, Data categorization, Information extraction, Data organization, Spreadsheet integration, Accuracy enhancement, Efficiency improvement, Error reduction, Python programming, Data processing, Data extraction, Text extraction

Automatic Passenger Counting on the Edge via Unsupervised Clustering

We present a device- and network-based solution for automatic passnger counting that operates on the edge in real time. The proposed solution consists of a low-cost WiFi scanner device equipped with custom algorithms for dealing with MAC address randomization. Our low-cost scanner is able to capture and analyze 802.11 probe requests emitted by passengers’ devices such as laptops, smartphones, and tablets. The device is configured with a Python data-processing pipeline that combines data coming from different types of sensors and processes them on the fly. For the analysis task, we have devised a lightweight version of the DBSCAN algorithm. Our software artifact is designed in a modular way in order to accommodate possible extensions of the pipeline, e.g., either additional filters or data sources. Furthermore, we exploit multi-threading and multi-processing for speeding up the entire computation. The proposed solution has been tested with different types of mobile devices, obtaining promising experimental results. In this paper, we present the key ingredients of our edge computing solution.

Intelligent recognition method of laser image based on big data analysis technology

In order to improve the recognition effect of laser images, this study designed an intelligent recognition method of laser images based on big data analysis technology. On the basis of setting up the laser holographic scanning device and parameters, the laser image is obtained by using the calibration method of vision system. In order to avoid the limitation of coordinate system in the process of laser image recognition, a rational function model with general attributes is constructed. Then, convolutional neural network is used to output the feature data of laser images, and Spark parallel support vector machine algorithm is used to complete the classification of laser images. Finally, the SVM classification model based on the big data analysis technology is constructed. The texture feature data can be input to quickly output the classification results of laser images, and then the intelligent classification and recognition of laser images can be realized according to the probability distribution. Experimental results show that this method can accurately identify the tiny features in laser images, and the recognition results have high peak signal-to-noise ratio and high recognition accuracy.

Line Scan Hyperspectral Imaging Framework for Open Source Low-Cost Platforms

With advancements in computer processing power and deep learning techniques, hyperspectral imaging is continually being explored for improved sensing applications in various fields. However, the high cost associated with such imaging platforms impedes their widespread use in spite of the availability of the needed processing power. In this paper, we develop a novel theoretical framework required for an open source ultra-low-cost hyperspectral imaging platform based on the line scan method suitable for remote sensing applications. Then, we demonstrate the design and fabrication of an open source platform using consumer-grade commercial off-the-shelf components that are both affordable and easily accessible to researchers and users. At the heart of the optical system is a consumer-grade spectroscope along with a basic galvanometer mirror that is widely used in laser scanning devices. The utilized pushbroom scanning method provides a very high spectral resolution of 2.8 nm, as tested against commercial spectral sensors. Since the resolution is limited by the slit width of the spectroscope, we also provide a deconvolution method for the line scan in order to improve the monochromatic spatial resolution. Finally, we provide a cost-effective testing method for the hyperspectral imaging platform where the results validate both the spectral and spatial performances of the platform.

Comparison of the accuracy of digital axillary thermometer (DAT) with infrared forehead skin thermometer (IFST) measurements in healthy newborns

Temperature is an important vital sign. Body temperature is generally measured whenever there is suspicion of fever, but in neonates’ hypothermia is considered even more serious than fever. There are studies in pediatric intensive care units comparing various invasive methods of temperature measurement.This was a cross sectional comparative study conducted in postnatal wards and outpatient department of a teaching hospital. All consecutive 348 healthy term neonates between 0-28 days of life whose parents consented for participation in the study were included. The axillary temp was taken with digital thermometer and forehead temperature were measured by temporal scanner device simultaneously. Doctor and caretaker both took the temperature measurement. Out of total 348 patients 114 (32.7%) were males and 234(67.2%) were females. Mean birth weight was 2800±400 grams. Mean axillary temperature was 98.34±0.81°F, and forehead temperature was 97.81±0.89°F (p=0.44). There was a positive correlation between temperature measured using digital and infrared thermometer (r=0.914, p=0.00). The mean difference was −0.07 with limits of agreement −0.71 to 0.57.Digital axillary temperature was higher and closer to normal than infrared forehead temperature. Temperature readings by forehead infrared thermometry agree well with those by axillary digital thermometry in neonates. Hence both methods of temperature measurement can be used in neonates although Infra-red temporal touch is much easier technique than digital axilla temperature measurement