Density Of Scan Lines Research Articles

Simultaneous reconstruction of 3D fluorescence distribution and object surface using structured light illumination and dual-camera detection

Fluorescence molecular tomography (FMT) serves as a noninvasive modality for visualizing volumetric fluorescence distribution within biological tissues, thereby proving to be an invaluable imaging tool for preclinical animal studies. The conventional FMT relies upon a point-by-point raster scan strategy, enhancing the dataset for subsequent reconstruction but concurrently elongating the data acquisition process. The resultant diminished temporal resolution has persistently posed a bottleneck, constraining its utility in dynamic imaging studies. We introduce a novel system capable of simultaneous FMT and surface extraction, which is attributed to the implementation of a rapid line scanning approach and dual-camera detection. The system performance was characterized through phantom experiments, while the influence of scanning line density on reconstruction outcomes has been systematically investigated via both simulation and experiments. In a proof-of-concept study, our approach successfully captures a moving fluorescence bolus in three dimensions with an elevated frame rate of approximately 2.5 seconds per frame, employing an optimized scan interval of 5 mm. The notable enhancement in the spatio-temporal resolution of FMT holds the potential to broaden its applications in dynamic imaging tasks, such as surgical navigation.

Hydrophilic properties of the aluminum alloy induced by femtosecond laser structuring

This study explored the changes in wetting property and surface morphology in aluminum alloy plates due to femtosecond laser structuring. The laser scanning produced a hierarchical micro- and nano-scale structure consisting of microchannels decorated by irregular shape particles. The surface morphology was controlled by laser power and scanning line density. The surface wettability gradually changed from hydrophilic to hydrophobic one due to various chemical reactions for low laser power and scanning line density. However, femtosecond laser structuring with appropriate laser power and scanning line density was demonstrated to maintain strong and stable hydrophilic properties of aluminum alloy surfaces.

Utilizing phase-modulated Lissajous to enhance spatial and temporal resolution of laser scanning microscopy

One of the main challenges in scanning microscopy is increasing the scanning speed without deteriorating the spatial resolution of the image. With Lissajous scanning, the image is available in a fraction of the time since it gathers scattered data from the entire field of view. Nevertheless, this method reduces the density of scan lines at the center of the image, thereby reducing the imaging resolution. This problem can be solved by phase modulation of the motion function of the scanner; however, the density of lines created by such designs is not always controllable. In this paper, simple relationships for determining the desired density over a large area are presented for selecting the appropriate phase modulation, in particular for microscopy applications. In addition, a confocal microscope was employed to image samples using the proposed relations to obtain temporal and spatial resolution two times higher than conventional Lissajous. The results demonstrated that the imaging speed can be significantly increased by using phase modulation accompanied by interpolation methods for image reconstruction.

Estimating size of finite fracture networks in layered reservoirs

Conductive fractures in petroleum reservoirs may be totally isolated or fully interconnected. There is an intermediate state between the two extremities. Partially fractured reservoirs include finite fracture networks (FFN), which are bundles of interconnected fractures embedded in a sea of isolated fractures. Devising measures for sizes of FFNs is crucial in estimating critical engineering aspects such as productivity index, production decline rate and expected ultimate recovery of wells especially in reservoirs with low matrix porosity and permeability. Here, we present results of statistical evaluation of FFN size in relation to fracture connectivity which is in essence the number of fracture intersections per fracture. The analysis is based on a large number of stochastic 2-dimensional (2D) Poisson models of sub-vertical layer bound fractures. Fracture length in the models has log normal or truncated power distribution and fracture strike has circular normal distribution. The models may have single or multiple fracture sets and various truncation modes with different probabilities.The analysis shows that number of fracture intersections per fracture can be accurately estimated by a fracture connectivity index, which is defined as product of facture scan-line density, average fracture length and sine of strike standard deviation. The statistically significant finding of this study is that the number of fractures within a FFN is an exponential function of fracture connectivity index. All three fracture properties defining the index can be measured on borehole image logs. Hence it should be possible to estimate fracture connectivity and corresponding FFN size from borehole image data. The analysis pertains to 2D fracture connectivity which is always the lower bound of number of fracture intersections in 3-dimensions. Therefore the exponential relationships must also hold for actual 3-dimensional layer-bound fractures with variable dips.

Geometry of layer-bound fractures based on fracture density and aperture-depth plots from resistivity image logs of deviated wells

High resolution borehole resistivity image logs provide valuable bedding and fracture data from subsurface rocks including fracture type, orientation and aperture. The present study shows that common average shape and aperture geometry of uniformly located layer-bound fractures can be inferred from scan-line density and aperture-depth plots using image log data from a deviated well.The proposed method extends the use of borehole image logs and allows 3-dimensional (3D) modeling of fractures and fractured layers from subsurface data. So far, such 3D fracture studies could only be conducted using outcrop data. The approach is quite robust because correspondence between fracture geometry and image log plots is independent of fracture length and orientation, and applies to any fracture shape and aperture geometry.Joint interpretation of fracture scan-line density and aperture-depth plots, and bedding picks from borehole images also helps differentiate isolated/dispersed, unbound and multilayer fractures. Abundance of fractures that breach bed boundaries gives an idea about the cohesive bonding strength of bedding contacts and pave the way to construct fracture stratigraphy with several fractured layers that are separated by interfaces of varying bonding strength or by ductile beds. 3D fracture geometry may also provide some information on the type and mode of fractures and geo-mechanical conditions under which the fractures were generated.

Numerical analysis of three-dimensional echo decorrelation imaging.

A numerical model for three-dimensional echo decorrelation imaging, a pulse-echo ultrasound method applicable to thermal ablation monitoring, is presented. Beam patterns for steered transmit and receive array apertures are combined with a three-dimensional numerical tissue model to yield beamformed scan lines in a pyramidal configuration, volumetric B-mode images, and spatial maps of normalized decorrelation between sequential image volumes. Simulated three-dimensional echo decorrelation images of random media are analyzed as estimators of local tissue reflectivity decoherence, mimicking thermal ablation effects. The estimation error is analyzed as a function of correlation window size, scan line density, and ensemble averaging of decorrelation maps.

Acquiring and visualizing 3D/4D ultrasound recordings of tongue motion

Ultrasound is increasingly common in speech and phonetics research as technology continues to improve. The first digital 3D/4D ultrasound system was utilized for speech research nearly a decade ago, but data access, processing, and visualization were limited to (non-speech) clinical imaging applications. Access to the raw (pulse-echo or scan-converted) image data is a critical step toward making 3D/4D ultrasound an effective tool for speech research. In addition, there is a need for technical characterization of 3D/4D ultrasound systems together with a presentation of their strengths and limitations for research. This paper gives a general technical description of ultrasound systems, beginning with conventional 2D image acquisition and working up toward 3D/4D systems. Emphasis is given to one particular system – the Philips EPIQ 7G system with xMatrix X6-1 digital 3D/4D transducer – for which access to raw scan-converted data is now possible. For parameter settings typical of general abdominal imaging, frame rates around 20 fps are easily achieved (with frame rates possible up to 173 fps depending on image volume size, scan line density, and imaging depth), with spatial resolution comparable to research-grade 2D transducers. Using a modified Philips foot pedal, ultrasound recordings can be made with synchronous audio, and time-aligned with a minimum uncertainty equal to the ultrasound frame duration. In speech research, frame rates around 20 fps – with corresponding time-alignment uncertainty near 50 ms – provide good 3D coverage and enable many new phonetics questions to be posed and addressed.

Resistivity Characterization of Solid Electrolyte Interphase on Lithium Ion Battery Silicon Anodes

Lithium-ion battery (LIB) technology plays a critical role the clean energy sector, with applications in electronic devices, electric and hybrid vehicles, and stationary energy storage. In order to improve battery efficiency and performance, novel materials must be developed and studied. Battery anode materials are of particular interest, and silicon has been selected for materials research due to its high theoretical storage capacity as well as the extensive existing knowledge regarding silicon material processing and fabrication. The initial cycling of a LIB, regardless of anode material, results in the formation of a solid electrolyte interphase (SEI) layer between the electrolyte and the anode. This passivating layer, consisting of decomposition products from the electrolyte solution, is critical to the reliability and performance of the battery. The SEI must be both electronically insulating and ionically conductive: permeable to lithium ions yet resistant to electron flow. The resistance can be inhomogeneous along the anode plane or perpendicular to it. To our knowledge, no characterization technique has been capable of measuring spatial variation in SEI resistivity. In order to measure SEI resistivity with nanometer-scale resolution, our group has utilized scanning spreading resistance microscopy (SSRM) with a specialized atomic force microscopy (AFM) system installed in an argon glove box to minimize sample exposure to oxygen and water. The setup employs a doped diamond coated silicon probe that exhibits high wear resistance and low electronic resistance. Through application of a sample-probe bias voltage while utilizing variable forces on the probe in AFM contact mode, the technique allows for the measurement of SEI resistivity laterally and vertically. The vertical depth of measurement is controllable by the applied probe force (as well as raster scan line density) and is thus capable of milling away SEI material to measure resistivity at defined depths. Subsequent AFM height measurement allows for measured resistance to be associated with the depth of measurement. The electronic system attached to the system measures current through the probe-sample with a logarithm-scale amplifier, which can be directly converted to resistance or resistivity. Our measurements of resistance vs. depth for SEIs formed on single-crystal silicon wafers [001] after a single cycle of lithiation/delithiation demonstrate strong trends for decrease in resistance as the probe penetrates deeper levels of the SEI. Such plots provide an interesting basis for the study of SEIs formed under different cycling conditions with distinct electrolyte solutions. Figure: (a) Schematic diagram of electronic setup of the described system, (b) resistance map at a depth of 43 nm on a SEI formed on a single-crystal silicon wafer [001], with a single cycle of lithiation (0.01 V for 5 hours) and delithiation (1.0 V for 5 hours) in a battery cell containing ethylene carbonate (EC) and diethyl carbonate(DEC) electrolytes, (c) topography map displaying the SEI depth of resistance mapping. Figure 1

Fast ground filtering for TLS data via Scanline Density Analysis

Terrestrial Laser Scanning (TLS) efficiently collects 3D information based on lidar (light detection and ranging) technology. TLS has been widely used in topographic mapping, engineering surveying, forestry, industrial facilities, cultural heritage, and so on. Ground filtering is a common procedure in lidar data processing, which separates the point cloud data into ground points and non-ground points. Effective ground filtering is helpful for subsequent procedures such as segmentation, classification, and modeling. Numerous ground filtering algorithms have been developed for Airborne Laser Scanning (ALS) data. However, many of these are error prone in application to TLS data because of its different angle of view and highly variable resolution. Further, many ground filtering techniques are limited in application within challenging topography and experience difficulty coping with some objects such as short vegetation, steep slopes, and so forth. Lastly, due to the large size of point cloud data, operations such as data traversing, multiple iterations, and neighbor searching significantly affect the computation efficiency. In order to overcome these challenges, we present an efficient ground filtering method for TLS data via a Scanline Density Analysis, which is very fast because it exploits the grid structure storing TLS data. The process first separates the ground candidates, density features, and unidentified points based on an analysis of point density within each scanline. Second, a region growth using the scan pattern is performed to cluster the ground candidates and further refine the ground points (clusters). In the experiment, the effectiveness, parameter robustness, and efficiency of the proposed method is demonstrated with datasets collected from an urban scene and a natural scene, respectively.

Modeling of local dielectric charging induced by line scan during SEM observation

Evolution in emission of secondary electrons and backscattered electrons from thermally oxidized silicon sample during a single line-scan of a focused electron beam was measured. The influence of charging-up of the sample surface on the electron emission was analytically modeled. The detected current Ic of these electrons decreased sharply at the initial scanning stage and turned steady. The ratio of Ic to incident primary-beam current (Ip) at the steady state could be expressed in terms of “scanning line density” (λin), i.e., the number of incident electrons per unit scan distance. It was found that the ratio of Ic/Ip increased monotonously with decreasing λin. Furthermore, no difference in the change of the Ic/Ip at the steady states was observed with interval, i.e., the time between consecutive single-line scans at the same position, ranging from 10 μs to 500 ms. This result indicates that attenuation of the charge at the sample surface during the single line-scan is neglectable. An analytical model was proposed for correlating Ic/Ip, the potential at the irradiated position (Vs) and λin. The calculated Ic/Ip coincided quantitatively with the experimentally determined ratio. Besides, the analytical model showed that higher magnitude and less variation in Ic/Ip during the single line-scan can be expected with lower λin, which was experimentally verified. The parameter λin can be equally controlled through Ip and the line-scan speed v.

Consideration of Scanning Line Density and Capture of Shape of Human Movement from 3D Laser Scanning Sensor Using Roundly Swinging Mechanism

A 3D SOKUIKI sensor (3D laser scanning sensor) with a roundly swinging mechanism can detect the range distance of a belt area at a certain vertical height and horizontal view angle without any converging points and without twisting any signal cables. It is useful for observing the movement of people and for capturing the shape of human movement. We analyzed the line-to-line distance as the scanning line density for this type of sensor. The entire belt area of directions is scanned twice by both positively and negatively inclined scanning lines in one period of a whole scan. The line-to-line distance depends on the vertical height and is dense at both vertical ends and sparse in the middle. As a result, the scanning density at center front is 1/2.5 (40%) compared to using ideal vertical direction control. Since ideal vertical direction control of a range-measuring beam is not technically possible at this time, this scanning density provided by the roundly swinging mechanism can be considered to be reasonably good and useful. The 3D SOKUIKI sensor using this roundly swinging mechanism can capture the shape of human movement.

ULTRASONIC IMAGING APPARATUS AND A METHOD OF OBTAINING ULTRASONIC IMAGES

An ultrasonic probe and a transmitter/receiver scan a 3D region using ultrasonic beams by raising the scanning line density of the transmission of ultrasonic beams for a region of interest compared to the scanning line density of the transmission of ultrasonic beams for regions other than the region of interest among the 3D regions. An image-generating part generates ultrasonic-image data of the 3D region, based on the received beams that have been obtained by the scan.

High-frame-rate echocardiography using diverging transmit beams and parallel receive beamforming

Echocardiography is a widely used modality for diagnosis of the heart. It enables observation of the shape of the heart and estimation of global heart function based on B-mode and M-mode imaging. Subsequently, methods for estimating myocardial strain and strain rate have been developed to evaluate regional heart function. Furthermore, it has recently been shown that measurements of transmural transition of myocardial contraction/relaxation and propagation of vibration caused by closure of a heart valve would be useful for evaluation of myocardial function and viscoelasticity. However, such measurements require a frame rate much higher than that achieved by conventional ultrasonic diagnostic equipment. In the present study, a method based on parallel receive beamforming was developed to achieve high-frame-rate (over 300Hz) echocardiography. To increase the frame rate, the number of transmits was reduced to 15 with angular intervals of 6°, and 16 receiving beams were created for each transmission to obtain the same number and density of scan lines as realized by conventional sector scanning. In addition, several transmits were compounded to obtain each scan line to reduce the differences in transmit-receive sensitivities among scan lines. The number of transmits for compounding was determined by considering the width of the transmit beam. For transmission, plane waves and diverging waves were investigated. Diverging waves showed better performance than plane waves because the widths of plane waves did not increase with the range distance from the ultrasonic probe, whereas lateral intervals of scan lines increased with range distance. The spatial resolution of the proposed method was validated using fine nylon wires. Although the widths at half-maxima of the point spread functions obtained by diverging waves were slightly larger than those obtained by conventional beamforming and parallel beamforming with plane waves, point spread functions very similar to those obtained by conventional beamforming could be realized by parallel beamforming with diverging beams and compounding. However, there was an increase in the lateral sidelobe level in the case of parallel beamforming with plane and diverging waves. Furthermore, the heart of a 23-year-old healthy male was measured. Although the contrast of the B-mode image obtained by the proposed method was degraded due to the increased sidelobe level, a frame rate of 316Hz, much higher than that realized by conventional sector scanning of several tens of Hertz, was realized with a full lateral field of view of 90°.

TH-B-203-01: Uniform Scanning and Energy Stacking with Proton Beams

Patients have received treatments with protonbeams using many different beam delivery techniques. The technique of uniform scanning with energy stacking has not often been discussed. The first part of this course will provide an introduction to the technique including terminology. Topics to be covered include: scanning modes and patterns; history of electron and light ion scanning beam use in the clinic; energy stacking methods; energy/range considerations; and radiobiology of scanned beams. Advantages and disadvantages of the technique will also be discussed along with a brief review of scanning electron beam incidents to underscore the importance of safety in the use of the technique. The second part of the course will provide a description of several potential hazards and some example mitigations for those hazards such as monitoring of the scanning magnet operation; monitoring of the delivered lateral fluence distribution; use of downstream MU detectors; MU rate checks; monitoring of the ratios of signals between MU detectors; and beam energy checks. The third part of the course will provide some practical aspects for using the technique. Optimizing the scan pattern to obtain a laterally uniform dose distribution and sharp penumbra includes consideration of the density of scan lines and the beam overscan distance beyond the collimator edges. Optimization of the weights of the individual energy stack layers to obtain a uniform depth dose distribution over the target includes consideration of the width of the peak of the non‐modulated depth dose distribution. Other parameters for which the user must be cognizant include the effective and virtual source distances for different magnet configurations and the minimum MU per layer which is a function of the MU rate and scanning frequency. The use of multi‐element detectors to efficiently measure dose distributions in the depth and lateral directions will additionally be addressed. Special considerations for quality assurance will also be discussed such as: the stability of spot size stability of scanning magnet operation; reproducibility of range modulation; and reproducibility of range shift at off‐axis positions. Learning Objectives: 1. Differentiate the uniform scanning and energy stacking technique from other beam delivery techniques. 2. Become familiar with the advantages disadvantages potential hazards and hazard mitigations associated with the technique. 3. Become familiar with methods required to implement the technique including optimization and quality assurance.

Microtribological/mechanical testing in 0, 1 and 2 dimensions: A comparative study on different materials

Nanomechanical testing can be classified by dimensions of lateral movement of the tip: starting with nanoindentation (0D), followed by scratching and linear oscillating wear (1D) and finally scanning/area wear (2D). In this paper a comparison of theses four techniques is made for three types of materials: AF45 glass (amorphous), silicon (hard, crystalline) and aluminium (soft, crystalline). The morphology of craters, the wear depth and the pile-up characteristic of all types of testing is evaluated as a function of load. While 0D- and 1D testing often result in linear dependence of wear depth as a function of load, 2D testing shows different behaviour: at low loads a low or zero wear rate is found while above a certain threshold wear increases significantly. The analysis of pile-up created at the crater edges shows that the transport of piled-up material out of the crater seems to be the dominant factor for this effect. While below a threshold pile-up is redistributed within the crater (ploughing wear), above the threshold it is moved out of the crater and deposited outside of the scanned area (cutting wear). A critical attack angle is believed to be the decisive factor for the change of wear mode. It has been determined to be 19 ± 2° for all materials. Additionally, for scanning wear (2D) the effect of density of scan lines on the wear depth is compared with multiple scanning the same area. It is found that doubling or quadruplicating the number of scan lines has not the same effect as scanning the same area twice or four times. Again the transport of piled-up material seems to be responsible for this effect.

Effects of Ultrasound Contrast During Tissue Velocity Imaging on Regional Left Ventricular Velocity, Strain, and Strain Rate Measurements

Strain (epsilon) rate (SR) imaging and left ventricular (LV) opacification with intravenous (IV) contrast both potentially decrease operator dependency in interpretation of stress echocardiography. The aim of this study was to evaluate whether contrast present during tissue velocity imaging (TVI) significantly affected measurements of velocity, epsilon, and SR. Secondly, we sought to evaluate whether increased scan line density improved feasibility of simultaneous TVI and contrast echocardiography. The 4-chamber LV view in 15 healthy volunteers and 25 patients was acquired at rest before and after IV injections of contrast using: (1) conventional TVI; (2) LV opacification with standard TVI added; and (3) modified LV opacification with doubled TVI line density. Velocity, SR, and epsilon curves, along with peak systolic velocity, peak systolic SR, and end-systolic epsilon, were assessed from midwall segments. IV contrast significantly reduced feasibility of TVI with standard settings, giving noisy data for SR and epsilon, particularly in the septum. Absolute values of peak systolic SR and end-systolic epsilon from adequately shaped curves were significantly higher with contrast compared with baseline. However, increased TVI line density significantly improved feasibility of velocity traces with contrast and decreased the level of noise in SR and epsilon. Furthermore, higher line density improved agreement between peak systolic velocity, peak systolic SR, and end-systolic epsilon measured with contrast, and corresponding precontrast values from the conventional TVI setting. SR imaging was not feasible performed with IV contrast during conventional TVI settings, and we do not recommend the clinical use of this combination. Increased TVI line density made velocity curves with contrast feasible and resulted in less noisy SR and epsilon curves, but variability in SR and epsilon measurements with contrast is still too high for clinical use.

Novel nanosized patterning technology based on electropulsed scanning probe microscopy

Scanning Probe Microscopes (SPM) have been used to change surfaces at nanometer scales. We report the deposition of user defined patterns in a controlled manner using an electropulsed SPM. The patterns were fabricated by applying −12 V electrical pulses in the 10–40-Hz range between a commercial CoCr conductive tip and a crystalline n-doped Si wafer. The tip damage during deposition is negligible as measurements on the same surface region before and after deposition show no detectable differences. Immediately after deposition, the same tip is used for measuring the fabricated patterns. Applying one isolated electrical pulse results in a pixel with a typical size of the order of 30 nm. By combining the scanning ability of the SPM with the atmospheric deposition induced by electrical pulses on the tip, patterns can be fabricated. For example, by applying electrical pulses during a 25×800-nm tip scan in AFM tapping mode, at 40 Hz, lines with 65-nm width by 828-nm length were obtained (in good agreement with the expected dimensions of 55×830 nm derived from the pixel size and the scan range). The height of the deposited patterns is of the order of 2 to 3 nm, and was found to increase with the density of scan lines. The RMS roughness of the deposited material is shown to be strongly dependent on the electrical pulse frequency. The smoother pattern surface results from the 40-Hz pulse frequency. No deposition was observed at higher frequencies.

Novel Nanosized Patterning Techniques Using An Electropulsed Scanning Probe Microscope

AbstractScanning Probe Microscopes (SPM) have been used to change surfaces at nanometer scales. We report the deposition of user defined patterns in a controlled manner using an electropulsed SPM. The patterns were fabricated by applying -12 V electrical pulses in the 10 to 40 Hz range between a commercial CoCr conductive tip and a crystalline n-doped Si wafer. The tip damage during deposition is negligible as measurements on the same surface region before and after deposition show no detectable differences. Immediately after deposition the same tip is used for measuring the fabricated patterns. Applying one isolated electrical pulse results in a pixel with a typical size of the order of 30 nm. By combining the scanning ability of the SPM with the atmospheric deposition induced by electrical pulses on the tip, patterns can be fabricated. For example, by applying electrical pulses during a 25 nm x 800 nm tip scan in AFM tapping mode, at 40 Hz, lines with 65 nm width by 828 nm length were obtained (in good agreement with the expected dimensions of 55 nm x 830 nm derived from the pixel size and the scan range). The height of the deposited patterns is of the order of 2 to 3 nm, and was found to increase with the density of scan lines. The RMS roughness of the deposited material is shown to be strongly dependent on the electrical pulse frequency. The smoother pattern surface results from the 40 Hz pulse frequency. No deposition was observed at higher frequencies.

Image Formation in Real-Time Ultrasound

A review of image formation in realftime ultrasound is presented. Te techni;que of echoranging combined with beam scanning is explained with illustrative; examples. Factors afcting: lateraliresolution are discussed. The interdependence of frame rate, scan line density, and scan range is seen.

Accuracy and Limitations in Medical Ultrasound

Accuracy and limitations of medical ultrasound are described in terms of several kinds of resolution, such as temporal, spatial, contrast and velocity resolution.Ultrasound speed of about 1500 m/s in human soft tissue, limits the number of frames per second, the viewing area and the scanning line density. There are trade-offs among these parameters. In color Doppler flow imaging, frame rate limitation is much more severe.Three kinds of spatial resolutions are defined as the range resolution, the lateral resolution and the slice width. A simple and practical drawing method for ultrasound beam width representing the lateral resolution is shown for non-focusing and focusing transducers. Upper and lower limitations of Doppler blood velocity measurements are described.